* doc/Makefile.am (config.texi): Set top_srcdir.
[deliverable/binutils-gdb.git] / gas / doc / as.texinfo
CommitLineData
252b5132 1\input texinfo @c -*-Texinfo-*-
f7e42eb4 2@c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
2da5c037 3@c 2001, 2002, 2003, 2004, 2005
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4@c Free Software Foundation, Inc.
5@c UPDATE!! On future updates--
6@c (1) check for new machine-dep cmdline options in
7@c md_parse_option definitions in config/tc-*.c
8@c (2) for platform-specific directives, examine md_pseudo_op
9@c in config/tc-*.c
10@c (3) for object-format specific directives, examine obj_pseudo_op
11@c in config/obj-*.c
12@c (4) portable directives in potable[] in read.c
13@c %**start of header
14@setfilename as.info
15@c ---config---
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16@macro gcctabopt{body}
17@code{\body\}
18@end macro
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19@c defaults, config file may override:
20@set have-stabs
21@c ---
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22@c man begin NAME
23@c ---
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24@include asconfig.texi
25@include gasver.texi
26@c ---
0285c67d 27@c man end
4a4c4a1d 28@c ---
252b5132 29@c common OR combinations of conditions
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30@ifset COFF
31@set COFF-ELF
32@end ifset
33@ifset ELF
34@set COFF-ELF
35@end ifset
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36@ifset AOUT
37@set aout-bout
38@end ifset
39@ifset ARM/Thumb
40@set ARM
41@end ifset
42@ifset BOUT
43@set aout-bout
44@end ifset
45@ifset H8/300
46@set H8
47@end ifset
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48@ifset SH
49@set H8
50@end ifset
51@ifset HPPA
52@set abnormal-separator
53@end ifset
54@c ------------
55@ifset GENERIC
56@settitle Using @value{AS}
57@end ifset
58@ifclear GENERIC
59@settitle Using @value{AS} (@value{TARGET})
60@end ifclear
61@setchapternewpage odd
62@c %**end of header
63
64@c @smallbook
65@c @set SMALL
66@c WARE! Some of the machine-dependent sections contain tables of machine
67@c instructions. Except in multi-column format, these tables look silly.
68@c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so
69@c the multi-col format is faked within @example sections.
70@c
71@c Again unfortunately, the natural size that fits on a page, for these tables,
72@c is different depending on whether or not smallbook is turned on.
73@c This matters, because of order: text flow switches columns at each page
74@c break.
75@c
76@c The format faked in this source works reasonably well for smallbook,
77@c not well for the default large-page format. This manual expects that if you
78@c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the
79@c tables in question. You can turn on one without the other at your
80@c discretion, of course.
81@ifinfo
82@set SMALL
83@c the insn tables look just as silly in info files regardless of smallbook,
84@c might as well show 'em anyways.
85@end ifinfo
86
87@ifinfo
88@format
89START-INFO-DIR-ENTRY
90* As: (as). The GNU assembler.
59455fb1 91* Gas: (as). The GNU assembler.
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92END-INFO-DIR-ENTRY
93@end format
94@end ifinfo
95
96@finalout
97@syncodeindex ky cp
98
99@ifinfo
100This file documents the GNU Assembler "@value{AS}".
101
0285c67d 102@c man begin COPYRIGHT
973eb340 103Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002 Free Software Foundation, Inc.
252b5132 104
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105Permission is granted to copy, distribute and/or modify this document
106under the terms of the GNU Free Documentation License, Version 1.1
107or any later version published by the Free Software Foundation;
108with no Invariant Sections, with no Front-Cover Texts, and with no
109Back-Cover Texts. A copy of the license is included in the
c1253627 110section entitled ``GNU Free Documentation License''.
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111
112@c man end
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113
114@ignore
115Permission is granted to process this file through Tex and print the
116results, provided the printed document carries copying permission
117notice identical to this one except for the removal of this paragraph
118(this paragraph not being relevant to the printed manual).
119
120@end ignore
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121@end ifinfo
122
123@titlepage
124@title Using @value{AS}
125@subtitle The @sc{gnu} Assembler
126@ifclear GENERIC
127@subtitle for the @value{TARGET} family
128@end ifclear
129@sp 1
130@subtitle Version @value{VERSION}
131@sp 1
132@sp 13
133The Free Software Foundation Inc. thanks The Nice Computer
134Company of Australia for loaning Dean Elsner to write the
a4fb0134 135first (Vax) version of @command{as} for Project @sc{gnu}.
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136The proprietors, management and staff of TNCCA thank FSF for
137distracting the boss while they got some work
138done.
139@sp 3
140@author Dean Elsner, Jay Fenlason & friends
141@page
142@tex
143{\parskip=0pt
144\hfill {\it Using {\tt @value{AS}}}\par
145\hfill Edited by Cygnus Support\par
146}
147%"boxit" macro for figures:
148%Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3)
149\gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt
150 \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil
151#2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline
152\gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box
153@end tex
154
155@vskip 0pt plus 1filll
973eb340 156Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002 Free Software Foundation, Inc.
252b5132 157
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158 Permission is granted to copy, distribute and/or modify this document
159 under the terms of the GNU Free Documentation License, Version 1.1
160 or any later version published by the Free Software Foundation;
161 with no Invariant Sections, with no Front-Cover Texts, and with no
162 Back-Cover Texts. A copy of the license is included in the
c1253627 163 section entitled ``GNU Free Documentation License''.
252b5132 164
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165@end titlepage
166
2e64b665 167@ifnottex
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168@node Top
169@top Using @value{AS}
170
a4fb0134 171This file is a user guide to the @sc{gnu} assembler @command{@value{AS}} version
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172@value{VERSION}.
173@ifclear GENERIC
a4fb0134 174This version of the file describes @command{@value{AS}} configured to generate
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175code for @value{TARGET} architectures.
176@end ifclear
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177
178This document is distributed under the terms of the GNU Free
179Documentation License. A copy of the license is included in the
c1253627 180section entitled ``GNU Free Documentation License''.
cf055d54 181
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182@menu
183* Overview:: Overview
184* Invoking:: Command-Line Options
185* Syntax:: Syntax
186* Sections:: Sections and Relocation
187* Symbols:: Symbols
188* Expressions:: Expressions
189* Pseudo Ops:: Assembler Directives
190* Machine Dependencies:: Machine Dependent Features
191* Reporting Bugs:: Reporting Bugs
192* Acknowledgements:: Who Did What
cf055d54 193* GNU Free Documentation License:: GNU Free Documentation License
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194* Index:: Index
195@end menu
2e64b665 196@end ifnottex
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197
198@node Overview
199@chapter Overview
200@iftex
a4fb0134 201This manual is a user guide to the @sc{gnu} assembler @command{@value{AS}}.
252b5132 202@ifclear GENERIC
a4fb0134 203This version of the manual describes @command{@value{AS}} configured to generate
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204code for @value{TARGET} architectures.
205@end ifclear
206@end iftex
207
208@cindex invocation summary
209@cindex option summary
210@cindex summary of options
a4fb0134 211Here is a brief summary of how to invoke @command{@value{AS}}. For details,
8dfa0188 212@pxref{Invoking,,Command-Line Options}.
252b5132 213
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214@c man title AS the portable GNU assembler.
215
a4fb0134 216@ignore
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217@c man begin SEEALSO
218gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}.
219@c man end
a4fb0134 220@end ignore
0285c67d 221
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222@c We don't use deffn and friends for the following because they seem
223@c to be limited to one line for the header.
224@smallexample
0285c67d 225@c man begin SYNOPSIS
caa32fe5 226@value{AS} [@b{-a}[@b{cdhlns}][=@var{file}]] [@b{--alternate}] [@b{-D}]
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227 [@b{--defsym} @var{sym}=@var{val}] [@b{-f}] [@b{-g}] [@b{--gstabs}]
228 [@b{--gstabs+}] [@b{--gdwarf-2}] [@b{--help}] [@b{-I} @var{dir}] [@b{-J}]
229 [@b{-K}] [@b{-L}] [@b{--listing-lhs-width}=@var{NUM}]
230 [@b{--listing-lhs-width2}=@var{NUM}] [@b{--listing-rhs-width}=@var{NUM}]
231 [@b{--listing-cont-lines}=@var{NUM}] [@b{--keep-locals}] [@b{-o}
232 @var{objfile}] [@b{-R}] [@b{--reduce-memory-overheads}] [@b{--statistics}]
233 [@b{-v}] [@b{-version}] [@b{--version}] [@b{-W}] [@b{--warn}]
234 [@b{--fatal-warnings}] [@b{-w}] [@b{-x}] [@b{-Z}] [@b{--target-help}]
235 [@var{target-options}] [@b{--}|@var{files} @dots{}]
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236@c
237@c Target dependent options are listed below. Keep the list sorted.
238@c Add an empty line for separation.
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239@ifset ALPHA
240
241@emph{Target Alpha options:}
242 [@b{-m@var{cpu}}]
243 [@b{-mdebug} | @b{-no-mdebug}]
244 [@b{-relax}] [@b{-g}] [@b{-G@var{size}}]
245 [@b{-F}] [@b{-32addr}]
246@end ifset
252b5132 247@ifset ARC
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248
249@emph{Target ARC options:}
250 [@b{-marc[5|6|7|8]}]
251 [@b{-EB}|@b{-EL}]
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252@end ifset
253@ifset ARM
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254
255@emph{Target ARM options:}
03b1477f 256@c Don't document the deprecated options
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HPN
257 [@b{-mcpu}=@var{processor}[+@var{extension}@dots{}]]
258 [@b{-march}=@var{architecture}[+@var{extension}@dots{}]]
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259 [@b{-mfpu}=@var{floating-point-format}]
260 [@b{-mfloat-abi}=@var{abi}]
d507cf36 261 [@b{-meabi}=@var{ver}]
03b1477f 262 [@b{-mthumb}]
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263 [@b{-EB}|@b{-EL}]
264 [@b{-mapcs-32}|@b{-mapcs-26}|@b{-mapcs-float}|
265 @b{-mapcs-reentrant}]
7f266840 266 [@b{-mthumb-interwork}] [@b{-k}]
252b5132 267@end ifset
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268@ifset CRIS
269
270@emph{Target CRIS options:}
271 [@b{--underscore} | @b{--no-underscore}]
272 [@b{--pic}] [@b{-N}]
273 [@b{--emulation=criself} | @b{--emulation=crisaout}]
ae57792d 274 [@b{--march=v0_v10} | @b{--march=v10} | @b{--march=v32} | @b{--march=common_v10_v32}]
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275@c Deprecated -- deliberately not documented.
276@c [@b{-h}] [@b{-H}]
277@end ifset
252b5132 278@ifset D10V
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279
280@emph{Target D10V options:}
281 [@b{-O}]
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282@end ifset
283@ifset D30V
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284
285@emph{Target D30V options:}
286 [@b{-O}|@b{-n}|@b{-N}]
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287@end ifset
288@ifset H8
c2dcd04e 289@c Renesas family chips have no machine-dependent assembler options
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290@end ifset
291@ifset HPPA
292@c HPPA has no machine-dependent assembler options (yet).
293@end ifset
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294@ifset I80386
295
296@emph{Target i386 options:}
12b55ccc 297 [@b{--32}|@b{--64}] [@b{-n}]
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298@end ifset
299@ifset I960
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300
301@emph{Target i960 options:}
252b5132 302@c see md_parse_option in tc-i960.c
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303 [@b{-ACA}|@b{-ACA_A}|@b{-ACB}|@b{-ACC}|@b{-AKA}|@b{-AKB}|
304 @b{-AKC}|@b{-AMC}]
305 [@b{-b}] [@b{-no-relax}]
252b5132 306@end ifset
587fe2b3 307@ifset IA64
a4fb0134 308
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309@emph{Target IA-64 options:}
310 [@b{-mconstant-gp}|@b{-mauto-pic}]
311 [@b{-milp32}|@b{-milp64}|@b{-mlp64}|@b{-mp64}]
312 [@b{-mle}|@b{mbe}]
8c2fda1d 313 [@b{-mtune=itanium1}|@b{-mtune=itanium2}]
970d6792 314 [@b{-munwind-check=warning}|@b{-munwind-check=error}]
91d777ee 315 [@b{-mhint.b=ok}|@b{-mhint.b=warning}|@b{-mhint.b=error}]
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316 [@b{-x}|@b{-xexplicit}] [@b{-xauto}] [@b{-xdebug}]
317@end ifset
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318@ifset IP2K
319
320@emph{Target IP2K options:}
321 [@b{-mip2022}|@b{-mip2022ext}]
322@end ifset
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323@ifset M32C
324
325@emph{Target M32C options:}
326 [@b{-m32c}|@b{-m16c}]
327@end ifset
587fe2b3 328@ifset M32R
9e32ca89 329
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330@emph{Target M32R options:}
331 [@b{--m32rx}|@b{--[no-]warn-explicit-parallel-conflicts}|
587fe2b3 332 @b{--W[n]p}]
ec694b89 333@end ifset
252b5132 334@ifset M680X0
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335
336@emph{Target M680X0 options:}
337 [@b{-l}] [@b{-m68000}|@b{-m68010}|@b{-m68020}|@dots{}]
252b5132 338@end ifset
60bcf0fa 339@ifset M68HC11
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340
341@emph{Target M68HC11 options:}
d01030e6 342 [@b{-m68hc11}|@b{-m68hc12}|@b{-m68hcs12}]
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343 [@b{-mshort}|@b{-mlong}]
344 [@b{-mshort-double}|@b{-mlong-double}]
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345 [@b{--force-long-branchs}] [@b{--short-branchs}]
346 [@b{--strict-direct-mode}] [@b{--print-insn-syntax}]
347 [@b{--print-opcodes}] [@b{--generate-example}]
348@end ifset
349@ifset MCORE
350
351@emph{Target MCORE options:}
352 [@b{-jsri2bsr}] [@b{-sifilter}] [@b{-relax}]
353 [@b{-mcpu=[210|340]}]
60bcf0fa 354@end ifset
252b5132 355@ifset MIPS
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356
357@emph{Target MIPS options:}
78849248 358 [@b{-nocpp}] [@b{-EL}] [@b{-EB}] [@b{-O}[@var{optimization level}]]
437ee9d5 359 [@b{-g}[@var{debug level}]] [@b{-G} @var{num}] [@b{-KPIC}] [@b{-call_shared}]
1ffcab4b 360 [@b{-non_shared}] [@b{-xgot}]
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361 [@b{-mabi}=@var{ABI}] [@b{-32}] [@b{-n32}] [@b{-64}] [@b{-mfp32}] [@b{-mgp32}]
362 [@b{-march}=@var{CPU}] [@b{-mtune}=@var{CPU}] [@b{-mips1}] [@b{-mips2}]
af7ee8bf 363 [@b{-mips3}] [@b{-mips4}] [@b{-mips5}] [@b{-mips32}] [@b{-mips32r2}]
5f74bc13 364 [@b{-mips64}] [@b{-mips64r2}]
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365 [@b{-construct-floats}] [@b{-no-construct-floats}]
366 [@b{-trap}] [@b{-no-break}] [@b{-break}] [@b{-no-trap}]
367 [@b{-mfix7000}] [@b{-mno-fix7000}]
368 [@b{-mips16}] [@b{-no-mips16}]
1f25f5d3 369 [@b{-mips3d}] [@b{-no-mips3d}]
deec1734 370 [@b{-mdmx}] [@b{-no-mdmx}]
2ef2b9ae 371 [@b{-mdsp}] [@b{-mno-dsp}]
ef2e4d86 372 [@b{-mmt}] [@b{-mno-mt}]
ecb4347a 373 [@b{-mdebug}] [@b{-no-mdebug}]
dcd410fe 374 [@b{-mpdr}] [@b{-mno-pdr}]
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375@end ifset
376@ifset MMIX
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377
378@emph{Target MMIX options:}
379 [@b{--fixed-special-register-names}] [@b{--globalize-symbols}]
380 [@b{--gnu-syntax}] [@b{--relax}] [@b{--no-predefined-symbols}]
381 [@b{--no-expand}] [@b{--no-merge-gregs}] [@b{-x}]
973eb340 382 [@b{--linker-allocated-gregs}]
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383@end ifset
384@ifset PDP11
385
386@emph{Target PDP11 options:}
387 [@b{-mpic}|@b{-mno-pic}] [@b{-mall}] [@b{-mno-extensions}]
388 [@b{-m}@var{extension}|@b{-mno-}@var{extension}]
389 [@b{-m}@var{cpu}] [@b{-m}@var{machine}]
390@end ifset
391@ifset PJ
392
393@emph{Target picoJava options:}
394 [@b{-mb}|@b{-me}]
395@end ifset
396@ifset PPC
397
398@emph{Target PowerPC options:}
399 [@b{-mpwrx}|@b{-mpwr2}|@b{-mpwr}|@b{-m601}|@b{-mppc}|@b{-mppc32}|@b{-m603}|@b{-m604}|
400 @b{-m403}|@b{-m405}|@b{-mppc64}|@b{-m620}|@b{-mppc64bridge}|@b{-mbooke}|
401 @b{-mbooke32}|@b{-mbooke64}]
402 [@b{-mcom}|@b{-many}|@b{-maltivec}] [@b{-memb}]
403 [@b{-mregnames}|@b{-mno-regnames}]
404 [@b{-mrelocatable}|@b{-mrelocatable-lib}]
405 [@b{-mlittle}|@b{-mlittle-endian}|@b{-mbig}|@b{-mbig-endian}]
406 [@b{-msolaris}|@b{-mno-solaris}]
407@end ifset
408@ifset SPARC
409
410@emph{Target SPARC options:}
411@c The order here is important. See c-sparc.texi.
412 [@b{-Av6}|@b{-Av7}|@b{-Av8}|@b{-Asparclet}|@b{-Asparclite}
413 @b{-Av8plus}|@b{-Av8plusa}|@b{-Av9}|@b{-Av9a}]
414 [@b{-xarch=v8plus}|@b{-xarch=v8plusa}] [@b{-bump}]
415 [@b{-32}|@b{-64}]
416@end ifset
417@ifset TIC54X
418
419@emph{Target TIC54X options:}
420 [@b{-mcpu=54[123589]}|@b{-mcpu=54[56]lp}] [@b{-mfar-mode}|@b{-mf}]
421 [@b{-merrors-to-file} @var{<filename>}|@b{-me} @var{<filename>}]
422@end ifset
423@ifset Z8000
424@c Z8000 has no machine-dependent assembler options
252b5132 425@end ifset
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426@ifset XTENSA
427
428@emph{Target Xtensa options:}
43cd72b9 429 [@b{--[no-]text-section-literals}] [@b{--[no-]absolute-literals}]
e0001a05 430 [@b{--[no-]target-align}] [@b{--[no-]longcalls}]
43cd72b9 431 [@b{--[no-]transform}]
9456465c 432 [@b{--rename-section} @var{oldname}=@var{newname}]
e0001a05 433@end ifset
0285c67d 434@c man end
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435@end smallexample
436
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437@c man begin OPTIONS
438
a4fb0134 439@table @gcctabopt
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440@item -a[cdhlmns]
441Turn on listings, in any of a variety of ways:
442
a4fb0134 443@table @gcctabopt
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444@item -ac
445omit false conditionals
446
447@item -ad
448omit debugging directives
449
450@item -ah
451include high-level source
452
453@item -al
454include assembly
455
456@item -am
457include macro expansions
458
459@item -an
460omit forms processing
461
462@item -as
463include symbols
464
465@item =file
466set the name of the listing file
467@end table
468
469You may combine these options; for example, use @samp{-aln} for assembly
470listing without forms processing. The @samp{=file} option, if used, must be
471the last one. By itself, @samp{-a} defaults to @samp{-ahls}.
472
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473@item --alternate
474Begin in alternate macro mode, see @ref{Altmacro,,@code{.altmacro}}.
475
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476@item -D
477Ignored. This option is accepted for script compatibility with calls to
478other assemblers.
479
480@item --defsym @var{sym}=@var{value}
481Define the symbol @var{sym} to be @var{value} before assembling the input file.
482@var{value} must be an integer constant. As in C, a leading @samp{0x}
483indicates a hexadecimal value, and a leading @samp{0} indicates an octal value.
484
485@item -f
486``fast''---skip whitespace and comment preprocessing (assume source is
487compiler output).
488
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489@item -g
490@itemx --gen-debug
491Generate debugging information for each assembler source line using whichever
492debug format is preferred by the target. This currently means either STABS,
493ECOFF or DWARF2.
494
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495@item --gstabs
496Generate stabs debugging information for each assembler line. This
497may help debugging assembler code, if the debugger can handle it.
498
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499@item --gstabs+
500Generate stabs debugging information for each assembler line, with GNU
501extensions that probably only gdb can handle, and that could make other
502debuggers crash or refuse to read your program. This
503may help debugging assembler code. Currently the only GNU extension is
504the location of the current working directory at assembling time.
505
329e276d 506@item --gdwarf-2
cdf82bcf 507Generate DWARF2 debugging information for each assembler line. This
c1253627 508may help debugging assembler code, if the debugger can handle it. Note---this
85a39694 509option is only supported by some targets, not all of them.
cdf82bcf 510
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511@item --help
512Print a summary of the command line options and exit.
513
ea20a7da
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514@item --target-help
515Print a summary of all target specific options and exit.
516
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517@item -I @var{dir}
518Add directory @var{dir} to the search list for @code{.include} directives.
519
520@item -J
521Don't warn about signed overflow.
522
523@item -K
524@ifclear DIFF-TBL-KLUGE
525This option is accepted but has no effect on the @value{TARGET} family.
526@end ifclear
527@ifset DIFF-TBL-KLUGE
528Issue warnings when difference tables altered for long displacements.
529@end ifset
530
531@item -L
532@itemx --keep-locals
533Keep (in the symbol table) local symbols. On traditional a.out systems
534these start with @samp{L}, but different systems have different local
535label prefixes.
536
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537@item --listing-lhs-width=@var{number}
538Set the maximum width, in words, of the output data column for an assembler
539listing to @var{number}.
540
541@item --listing-lhs-width2=@var{number}
542Set the maximum width, in words, of the output data column for continuation
543lines in an assembler listing to @var{number}.
544
545@item --listing-rhs-width=@var{number}
546Set the maximum width of an input source line, as displayed in a listing, to
547@var{number} bytes.
548
549@item --listing-cont-lines=@var{number}
550Set the maximum number of lines printed in a listing for a single line of input
551to @var{number} + 1.
552
252b5132 553@item -o @var{objfile}
a4fb0134 554Name the object-file output from @command{@value{AS}} @var{objfile}.
252b5132
RH
555
556@item -R
557Fold the data section into the text section.
558
4bdd3565
NC
559@kindex --hash-size=@var{number}
560Set the default size of GAS's hash tables to a prime number close to
561@var{number}. Increasing this value can reduce the length of time it takes the
562assembler to perform its tasks, at the expense of increasing the assembler's
563memory requirements. Similarly reducing this value can reduce the memory
564requirements at the expense of speed.
565
566@item --reduce-memory-overheads
567This option reduces GAS's memory requirements, at the expense of making the
568assembly processes slower. Currently this switch is a synonym for
569@samp{--hash-size=4051}, but in the future it may have other effects as well.
570
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RH
571@item --statistics
572Print the maximum space (in bytes) and total time (in seconds) used by
573assembly.
574
575@item --strip-local-absolute
576Remove local absolute symbols from the outgoing symbol table.
577
578@item -v
579@itemx -version
a4fb0134 580Print the @command{as} version.
252b5132
RH
581
582@item --version
a4fb0134 583Print the @command{as} version and exit.
252b5132
RH
584
585@item -W
2bdd6cf5 586@itemx --no-warn
252b5132
RH
587Suppress warning messages.
588
2bdd6cf5
GK
589@item --fatal-warnings
590Treat warnings as errors.
591
592@item --warn
593Don't suppress warning messages or treat them as errors.
594
252b5132
RH
595@item -w
596Ignored.
597
598@item -x
599Ignored.
600
601@item -Z
602Generate an object file even after errors.
603
604@item -- | @var{files} @dots{}
605Standard input, or source files to assemble.
606
607@end table
608
609@ifset ARC
610The following options are available when @value{AS} is configured for
611an ARC processor.
612
a4fb0134 613@table @gcctabopt
0d2bcfaf
NC
614@item -marc[5|6|7|8]
615This option selects the core processor variant.
616@item -EB | -EL
617Select either big-endian (-EB) or little-endian (-EL) output.
252b5132
RH
618@end table
619@end ifset
620
621@ifset ARM
622The following options are available when @value{AS} is configured for the ARM
623processor family.
624
a4fb0134 625@table @gcctabopt
92081f48 626@item -mcpu=@var{processor}[+@var{extension}@dots{}]
cdf82bcf 627Specify which ARM processor variant is the target.
92081f48 628@item -march=@var{architecture}[+@var{extension}@dots{}]
cdf82bcf 629Specify which ARM architecture variant is used by the target.
03b1477f 630@item -mfpu=@var{floating-point-format}
a349d9dd 631Select which Floating Point architecture is the target.
33a392fb
PB
632@item -mfloat-abi=@var{abi}
633Select which floating point ABI is in use.
03b1477f
RE
634@item -mthumb
635Enable Thumb only instruction decoding.
7f266840 636@item -mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant
252b5132
RH
637Select which procedure calling convention is in use.
638@item -EB | -EL
639Select either big-endian (-EB) or little-endian (-EL) output.
cdf82bcf
NC
640@item -mthumb-interwork
641Specify that the code has been generated with interworking between Thumb and
642ARM code in mind.
643@item -k
644Specify that PIC code has been generated.
252b5132
RH
645@end table
646@end ifset
647
328eb32e
HPN
648@ifset CRIS
649See the info pages for documentation of the CRIS-specific options.
650@end ifset
651
252b5132
RH
652@ifset D10V
653The following options are available when @value{AS} is configured for
654a D10V processor.
a4fb0134 655@table @gcctabopt
252b5132
RH
656@cindex D10V optimization
657@cindex optimization, D10V
658@item -O
659Optimize output by parallelizing instructions.
660@end table
661@end ifset
662
663@ifset D30V
664The following options are available when @value{AS} is configured for a D30V
665processor.
a4fb0134 666@table @gcctabopt
252b5132
RH
667@cindex D30V optimization
668@cindex optimization, D30V
669@item -O
670Optimize output by parallelizing instructions.
671
672@cindex D30V nops
673@item -n
674Warn when nops are generated.
675
676@cindex D30V nops after 32-bit multiply
677@item -N
678Warn when a nop after a 32-bit multiply instruction is generated.
679@end table
680@end ifset
681
682@ifset I960
683The following options are available when @value{AS} is configured for the
684Intel 80960 processor.
685
a4fb0134 686@table @gcctabopt
252b5132
RH
687@item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
688Specify which variant of the 960 architecture is the target.
689
690@item -b
691Add code to collect statistics about branches taken.
692
693@item -no-relax
694Do not alter compare-and-branch instructions for long displacements;
695error if necessary.
696
697@end table
698@end ifset
699
a40cbfa3
NC
700@ifset IP2K
701The following options are available when @value{AS} is configured for the
ec88d317 702Ubicom IP2K series.
a40cbfa3
NC
703
704@table @gcctabopt
705
706@item -mip2022ext
707Specifies that the extended IP2022 instructions are allowed.
708
709@item -mip2022
8dfa0188 710Restores the default behaviour, which restricts the permitted instructions to
a40cbfa3
NC
711just the basic IP2022 ones.
712
713@end table
714@end ifset
715
49f58d10
JB
716@ifset M32C
717The following options are available when @value{AS} is configured for the
718Renesas M32C and M16C processors.
719
720@table @gcctabopt
721
722@item -m32c
723Assemble M32C instructions.
724
725@item -m16c
726Assemble M16C instructions (the default).
727
728@end table
729@end ifset
730
ec694b89
NC
731@ifset M32R
732The following options are available when @value{AS} is configured for the
26597c86 733Renesas M32R (formerly Mitsubishi M32R) series.
ec694b89 734
a4fb0134 735@table @gcctabopt
ec694b89
NC
736
737@item --m32rx
738Specify which processor in the M32R family is the target. The default
739is normally the M32R, but this option changes it to the M32RX.
740
741@item --warn-explicit-parallel-conflicts or --Wp
742Produce warning messages when questionable parallel constructs are
743encountered.
744
745@item --no-warn-explicit-parallel-conflicts or --Wnp
746Do not produce warning messages when questionable parallel constructs are
747encountered.
748
749@end table
750@end ifset
252b5132
RH
751
752@ifset M680X0
753The following options are available when @value{AS} is configured for the
754Motorola 68000 series.
755
a4fb0134 756@table @gcctabopt
252b5132
RH
757
758@item -l
759Shorten references to undefined symbols, to one word instead of two.
760
0285c67d
NC
761@item -m68000 | -m68008 | -m68010 | -m68020 | -m68030
762@itemx | -m68040 | -m68060 | -m68302 | -m68331 | -m68332
763@itemx | -m68333 | -m68340 | -mcpu32 | -m5200
252b5132
RH
764Specify what processor in the 68000 family is the target. The default
765is normally the 68020, but this can be changed at configuration time.
766
767@item -m68881 | -m68882 | -mno-68881 | -mno-68882
768The target machine does (or does not) have a floating-point coprocessor.
769The default is to assume a coprocessor for 68020, 68030, and cpu32. Although
770the basic 68000 is not compatible with the 68881, a combination of the
771two can be specified, since it's possible to do emulation of the
772coprocessor instructions with the main processor.
773
774@item -m68851 | -mno-68851
775The target machine does (or does not) have a memory-management
776unit coprocessor. The default is to assume an MMU for 68020 and up.
777
778@end table
779@end ifset
780
e135f41b
NC
781@ifset PDP11
782
783For details about the PDP-11 machine dependent features options,
784see @ref{PDP-11-Options}.
785
a4fb0134 786@table @gcctabopt
e135f41b
NC
787@item -mpic | -mno-pic
788Generate position-independent (or position-dependent) code. The
a4fb0134 789default is @option{-mpic}.
e135f41b
NC
790
791@item -mall
792@itemx -mall-extensions
793Enable all instruction set extensions. This is the default.
794
795@item -mno-extensions
796Disable all instruction set extensions.
797
798@item -m@var{extension} | -mno-@var{extension}
799Enable (or disable) a particular instruction set extension.
800
801@item -m@var{cpu}
802Enable the instruction set extensions supported by a particular CPU, and
803disable all other extensions.
804
805@item -m@var{machine}
806Enable the instruction set extensions supported by a particular machine
807model, and disable all other extensions.
808@end table
809
810@end ifset
811
041dd5a9
ILT
812@ifset PJ
813The following options are available when @value{AS} is configured for
814a picoJava processor.
815
a4fb0134 816@table @gcctabopt
041dd5a9
ILT
817
818@cindex PJ endianness
819@cindex endianness, PJ
820@cindex big endian output, PJ
821@item -mb
822Generate ``big endian'' format output.
823
824@cindex little endian output, PJ
825@item -ml
826Generate ``little endian'' format output.
827
828@end table
829@end ifset
830
60bcf0fa
NC
831@ifset M68HC11
832The following options are available when @value{AS} is configured for the
833Motorola 68HC11 or 68HC12 series.
834
a4fb0134 835@table @gcctabopt
60bcf0fa 836
d01030e6 837@item -m68hc11 | -m68hc12 | -m68hcs12
60bcf0fa
NC
838Specify what processor is the target. The default is
839defined by the configuration option when building the assembler.
840
2f904664
SC
841@item -mshort
842Specify to use the 16-bit integer ABI.
843
844@item -mlong
845Specify to use the 32-bit integer ABI.
846
847@item -mshort-double
848Specify to use the 32-bit double ABI.
849
850@item -mlong-double
851Specify to use the 64-bit double ABI.
852
60bcf0fa
NC
853@item --force-long-branchs
854Relative branches are turned into absolute ones. This concerns
855conditional branches, unconditional branches and branches to a
856sub routine.
857
858@item -S | --short-branchs
859Do not turn relative branchs into absolute ones
860when the offset is out of range.
861
862@item --strict-direct-mode
863Do not turn the direct addressing mode into extended addressing mode
864when the instruction does not support direct addressing mode.
865
866@item --print-insn-syntax
867Print the syntax of instruction in case of error.
868
869@item --print-opcodes
870print the list of instructions with syntax and then exit.
871
872@item --generate-example
873print an example of instruction for each possible instruction and then exit.
a4fb0134 874This option is only useful for testing @command{@value{AS}}.
60bcf0fa
NC
875
876@end table
877@end ifset
878
252b5132 879@ifset SPARC
a4fb0134 880The following options are available when @command{@value{AS}} is configured
252b5132
RH
881for the SPARC architecture:
882
a4fb0134 883@table @gcctabopt
252b5132
RH
884@item -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite
885@itemx -Av8plus | -Av8plusa | -Av9 | -Av9a
886Explicitly select a variant of the SPARC architecture.
887
888@samp{-Av8plus} and @samp{-Av8plusa} select a 32 bit environment.
889@samp{-Av9} and @samp{-Av9a} select a 64 bit environment.
890
891@samp{-Av8plusa} and @samp{-Av9a} enable the SPARC V9 instruction set with
892UltraSPARC extensions.
893
894@item -xarch=v8plus | -xarch=v8plusa
895For compatibility with the Solaris v9 assembler. These options are
896equivalent to -Av8plus and -Av8plusa, respectively.
897
898@item -bump
899Warn when the assembler switches to another architecture.
900@end table
901@end ifset
902
39bec121
TW
903@ifset TIC54X
904The following options are available when @value{AS} is configured for the 'c54x
905architecture.
906
a4fb0134 907@table @gcctabopt
39bec121
TW
908@item -mfar-mode
909Enable extended addressing mode. All addresses and relocations will assume
910extended addressing (usually 23 bits).
911@item -mcpu=@var{CPU_VERSION}
912Sets the CPU version being compiled for.
913@item -merrors-to-file @var{FILENAME}
914Redirect error output to a file, for broken systems which don't support such
915behaviour in the shell.
916@end table
917@end ifset
918
252b5132
RH
919@ifset MIPS
920The following options are available when @value{AS} is configured for
437ee9d5 921a @sc{mips} processor.
252b5132 922
a4fb0134 923@table @gcctabopt
252b5132
RH
924@item -G @var{num}
925This option sets the largest size of an object that can be referenced
926implicitly with the @code{gp} register. It is only accepted for targets that
927use ECOFF format, such as a DECstation running Ultrix. The default value is 8.
928
929@cindex MIPS endianness
930@cindex endianness, MIPS
931@cindex big endian output, MIPS
932@item -EB
933Generate ``big endian'' format output.
934
935@cindex little endian output, MIPS
936@item -EL
937Generate ``little endian'' format output.
938
939@cindex MIPS ISA
940@item -mips1
941@itemx -mips2
942@itemx -mips3
e7af610e 943@itemx -mips4
437ee9d5 944@itemx -mips5
e7af610e 945@itemx -mips32
af7ee8bf 946@itemx -mips32r2
4058e45f 947@itemx -mips64
5f74bc13 948@itemx -mips64r2
437ee9d5
TS
949Generate code for a particular @sc{mips} Instruction Set Architecture level.
950@samp{-mips1} is an alias for @samp{-march=r3000}, @samp{-mips2} is an
951alias for @samp{-march=r6000}, @samp{-mips3} is an alias for
952@samp{-march=r4000} and @samp{-mips4} is an alias for @samp{-march=r8000}.
5f74bc13
CD
953@samp{-mips5}, @samp{-mips32}, @samp{-mips32r2}, @samp{-mips64}, and
954@samp{-mips64r2}
af7ee8bf 955correspond to generic
5f74bc13
CD
956@samp{MIPS V}, @samp{MIPS32}, @samp{MIPS32 Release 2}, @samp{MIPS64},
957and @samp{MIPS64 Release 2}
958ISA processors, respectively.
437ee9d5
TS
959
960@item -march=@var{CPU}
961Generate code for a particular @sc{mips} cpu.
962
963@item -mtune=@var{cpu}
964Schedule and tune for a particular @sc{mips} cpu.
965
966@item -mfix7000
967@itemx -mno-fix7000
968Cause nops to be inserted if the read of the destination register
969of an mfhi or mflo instruction occurs in the following two instructions.
970
ecb4347a
DJ
971@item -mdebug
972@itemx -no-mdebug
973Cause stabs-style debugging output to go into an ECOFF-style .mdebug
974section instead of the standard ELF .stabs sections.
975
dcd410fe
RO
976@item -mpdr
977@itemx -mno-pdr
978Control generation of @code{.pdr} sections.
979
437ee9d5
TS
980@item -mgp32
981@itemx -mfp32
982The register sizes are normally inferred from the ISA and ABI, but these
983flags force a certain group of registers to be treated as 32 bits wide at
984all times. @samp{-mgp32} controls the size of general-purpose registers
985and @samp{-mfp32} controls the size of floating-point registers.
986
987@item -mips16
988@itemx -no-mips16
989Generate code for the MIPS 16 processor. This is equivalent to putting
990@code{.set mips16} at the start of the assembly file. @samp{-no-mips16}
991turns off this option.
252b5132 992
1f25f5d3
CD
993@item -mips3d
994@itemx -no-mips3d
995Generate code for the MIPS-3D Application Specific Extension.
996This tells the assembler to accept MIPS-3D instructions.
997@samp{-no-mips3d} turns off this option.
998
deec1734
CD
999@item -mdmx
1000@itemx -no-mdmx
1001Generate code for the MDMX Application Specific Extension.
1002This tells the assembler to accept MDMX instructions.
1003@samp{-no-mdmx} turns off this option.
1004
2ef2b9ae
CF
1005@item -mdsp
1006@itemx -mno-dsp
1007Generate code for the DSP Application Specific Extension.
1008This tells the assembler to accept DSP instructions.
1009@samp{-mno-dsp} turns off this option.
1010
ef2e4d86
CF
1011@item -mmt
1012@itemx -mno-mt
1013Generate code for the MT Application Specific Extension.
1014This tells the assembler to accept MT instructions.
1015@samp{-mno-mt} turns off this option.
1016
437ee9d5
TS
1017@item --construct-floats
1018@itemx --no-construct-floats
1019The @samp{--no-construct-floats} option disables the construction of
1020double width floating point constants by loading the two halves of the
1021value into the two single width floating point registers that make up
1022the double width register. By default @samp{--construct-floats} is
1023selected, allowing construction of these floating point constants.
252b5132
RH
1024
1025@cindex emulation
1026@item --emulation=@var{name}
a4fb0134 1027This option causes @command{@value{AS}} to emulate @command{@value{AS}} configured
252b5132
RH
1028for some other target, in all respects, including output format (choosing
1029between ELF and ECOFF only), handling of pseudo-opcodes which may generate
1030debugging information or store symbol table information, and default
1031endianness. The available configuration names are: @samp{mipsecoff},
1032@samp{mipself}, @samp{mipslecoff}, @samp{mipsbecoff}, @samp{mipslelf},
1033@samp{mipsbelf}. The first two do not alter the default endianness from that
1034of the primary target for which the assembler was configured; the others change
1035the default to little- or big-endian as indicated by the @samp{b} or @samp{l}
1036in the name. Using @samp{-EB} or @samp{-EL} will override the endianness
1037selection in any case.
1038
1039This option is currently supported only when the primary target
437ee9d5 1040@command{@value{AS}} is configured for is a @sc{mips} ELF or ECOFF target.
252b5132
RH
1041Furthermore, the primary target or others specified with
1042@samp{--enable-targets=@dots{}} at configuration time must include support for
1043the other format, if both are to be available. For example, the Irix 5
1044configuration includes support for both.
1045
1046Eventually, this option will support more configurations, with more
1047fine-grained control over the assembler's behavior, and will be supported for
1048more processors.
1049
1050@item -nocpp
a4fb0134 1051@command{@value{AS}} ignores this option. It is accepted for compatibility with
252b5132
RH
1052the native tools.
1053
252b5132
RH
1054@item --trap
1055@itemx --no-trap
1056@itemx --break
1057@itemx --no-break
1058Control how to deal with multiplication overflow and division by zero.
1059@samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception
1060(and only work for Instruction Set Architecture level 2 and higher);
1061@samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a
1062break exception.
63486801
L
1063
1064@item -n
a4fb0134 1065When this option is used, @command{@value{AS}} will issue a warning every
63486801 1066time it generates a nop instruction from a macro.
252b5132
RH
1067@end table
1068@end ifset
1069
1070@ifset MCORE
1071The following options are available when @value{AS} is configured for
1072an MCore processor.
1073
a4fb0134 1074@table @gcctabopt
252b5132
RH
1075@item -jsri2bsr
1076@itemx -nojsri2bsr
1077Enable or disable the JSRI to BSR transformation. By default this is enabled.
1078The command line option @samp{-nojsri2bsr} can be used to disable it.
1079
1080@item -sifilter
1081@itemx -nosifilter
1082Enable or disable the silicon filter behaviour. By default this is disabled.
a349d9dd 1083The default can be overridden by the @samp{-sifilter} command line option.
252b5132
RH
1084
1085@item -relax
1086Alter jump instructions for long displacements.
1087
ec694b89
NC
1088@item -mcpu=[210|340]
1089Select the cpu type on the target hardware. This controls which instructions
1090can be assembled.
1091
1092@item -EB
1093Assemble for a big endian target.
1094
1095@item -EL
1096Assemble for a little endian target.
252b5132
RH
1097
1098@end table
1099@end ifset
1100
3c3bdf30
NC
1101@ifset MMIX
1102See the info pages for documentation of the MMIX-specific options.
1103@end ifset
1104
e0001a05
NC
1105@ifset XTENSA
1106The following options are available when @value{AS} is configured for
1107an Xtensa processor.
1108
1109@table @gcctabopt
e0001a05
NC
1110@item --text-section-literals | --no-text-section-literals
1111With @option{--text-@-section-@-literals}, literal pools are interspersed
1112in the text section. The default is
1113@option{--no-@-text-@-section-@-literals}, which places literals in a
43cd72b9
BW
1114separate section in the output file. These options only affect literals
1115referenced via PC-relative @code{L32R} instructions; literals for
1116absolute mode @code{L32R} instructions are handled separately.
1117
1118@item --absolute-literals | --no-absolute-literals
1119Indicate to the assembler whether @code{L32R} instructions use absolute
1120or PC-relative addressing. The default is to assume absolute addressing
1121if the Xtensa processor includes the absolute @code{L32R} addressing
1122option. Otherwise, only the PC-relative @code{L32R} mode can be used.
e0001a05
NC
1123
1124@item --target-align | --no-target-align
1125Enable or disable automatic alignment to reduce branch penalties at the
1126expense of some code density. The default is @option{--target-@-align}.
1127
1128@item --longcalls | --no-longcalls
1129Enable or disable transformation of call instructions to allow calls
1130across a greater range of addresses. The default is
1131@option{--no-@-longcalls}.
43cd72b9
BW
1132
1133@item --transform | --no-transform
1134Enable or disable all assembler transformations of Xtensa instructions.
1135The default is @option{--transform};
1136@option{--no-transform} should be used only in the rare cases when the
1137instructions must be exactly as specified in the assembly source.
e0001a05
NC
1138@end table
1139@end ifset
1140
0285c67d
NC
1141@c man end
1142
252b5132
RH
1143@menu
1144* Manual:: Structure of this Manual
1145* GNU Assembler:: The GNU Assembler
1146* Object Formats:: Object File Formats
1147* Command Line:: Command Line
1148* Input Files:: Input Files
1149* Object:: Output (Object) File
1150* Errors:: Error and Warning Messages
1151@end menu
1152
1153@node Manual
1154@section Structure of this Manual
1155
1156@cindex manual, structure and purpose
1157This manual is intended to describe what you need to know to use
a4fb0134 1158@sc{gnu} @command{@value{AS}}. We cover the syntax expected in source files, including
252b5132 1159notation for symbols, constants, and expressions; the directives that
a4fb0134 1160@command{@value{AS}} understands; and of course how to invoke @command{@value{AS}}.
252b5132
RH
1161
1162@ifclear GENERIC
1163We also cover special features in the @value{TARGET}
a4fb0134 1164configuration of @command{@value{AS}}, including assembler directives.
252b5132
RH
1165@end ifclear
1166@ifset GENERIC
1167This manual also describes some of the machine-dependent features of
1168various flavors of the assembler.
1169@end ifset
1170
1171@cindex machine instructions (not covered)
1172On the other hand, this manual is @emph{not} intended as an introduction
1173to programming in assembly language---let alone programming in general!
1174In a similar vein, we make no attempt to introduce the machine
1175architecture; we do @emph{not} describe the instruction set, standard
1176mnemonics, registers or addressing modes that are standard to a
1177particular architecture.
1178@ifset GENERIC
1179You may want to consult the manufacturer's
1180machine architecture manual for this information.
1181@end ifset
1182@ifclear GENERIC
1183@ifset H8/300
1184For information on the H8/300 machine instruction set, see @cite{H8/300
c2dcd04e
NC
1185Series Programming Manual}. For the H8/300H, see @cite{H8/300H Series
1186Programming Manual} (Renesas).
252b5132 1187@end ifset
252b5132 1188@ifset SH
ef230218
JR
1189For information on the Renesas (formerly Hitachi) / SuperH SH machine instruction set,
1190see @cite{SH-Microcomputer User's Manual} (Renesas) or
1191@cite{SH-4 32-bit CPU Core Architecture} (SuperH) and
1192@cite{SuperH (SH) 64-Bit RISC Series} (SuperH).
252b5132
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1193@end ifset
1194@ifset Z8000
1195For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual}
1196@end ifset
1197@end ifclear
1198
1199@c I think this is premature---doc@cygnus.com, 17jan1991
1200@ignore
1201Throughout this manual, we assume that you are running @dfn{GNU},
1202the portable operating system from the @dfn{Free Software
1203Foundation, Inc.}. This restricts our attention to certain kinds of
1204computer (in particular, the kinds of computers that @sc{gnu} can run on);
1205once this assumption is granted examples and definitions need less
1206qualification.
1207
a4fb0134 1208@command{@value{AS}} is part of a team of programs that turn a high-level
252b5132
RH
1209human-readable series of instructions into a low-level
1210computer-readable series of instructions. Different versions of
a4fb0134 1211@command{@value{AS}} are used for different kinds of computer.
252b5132
RH
1212@end ignore
1213
1214@c There used to be a section "Terminology" here, which defined
1215@c "contents", "byte", "word", and "long". Defining "word" to any
1216@c particular size is confusing when the .word directive may generate 16
1217@c bits on one machine and 32 bits on another; in general, for the user
1218@c version of this manual, none of these terms seem essential to define.
1219@c They were used very little even in the former draft of the manual;
1220@c this draft makes an effort to avoid them (except in names of
1221@c directives).
1222
1223@node GNU Assembler
1224@section The GNU Assembler
1225
0285c67d
NC
1226@c man begin DESCRIPTION
1227
a4fb0134 1228@sc{gnu} @command{as} is really a family of assemblers.
252b5132 1229@ifclear GENERIC
a4fb0134 1230This manual describes @command{@value{AS}}, a member of that family which is
252b5132
RH
1231configured for the @value{TARGET} architectures.
1232@end ifclear
1233If you use (or have used) the @sc{gnu} assembler on one architecture, you
1234should find a fairly similar environment when you use it on another
1235architecture. Each version has much in common with the others,
1236including object file formats, most assembler directives (often called
1237@dfn{pseudo-ops}) and assembler syntax.@refill
1238
1239@cindex purpose of @sc{gnu} assembler
a4fb0134 1240@command{@value{AS}} is primarily intended to assemble the output of the
252b5132 1241@sc{gnu} C compiler @code{@value{GCC}} for use by the linker
a4fb0134 1242@code{@value{LD}}. Nevertheless, we've tried to make @command{@value{AS}}
252b5132
RH
1243assemble correctly everything that other assemblers for the same
1244machine would assemble.
1245@ifset VAX
1246Any exceptions are documented explicitly (@pxref{Machine Dependencies}).
1247@end ifset
1248@ifset M680X0
1249@c This remark should appear in generic version of manual; assumption
1250@c here is that generic version sets M680x0.
a4fb0134 1251This doesn't mean @command{@value{AS}} always uses the same syntax as another
252b5132
RH
1252assembler for the same architecture; for example, we know of several
1253incompatible versions of 680x0 assembly language syntax.
1254@end ifset
1255
0285c67d
NC
1256@c man end
1257
a4fb0134 1258Unlike older assemblers, @command{@value{AS}} is designed to assemble a source
252b5132
RH
1259program in one pass of the source file. This has a subtle impact on the
1260@kbd{.org} directive (@pxref{Org,,@code{.org}}).
1261
1262@node Object Formats
1263@section Object File Formats
1264
1265@cindex object file format
1266The @sc{gnu} assembler can be configured to produce several alternative
1267object file formats. For the most part, this does not affect how you
1268write assembly language programs; but directives for debugging symbols
1269are typically different in different file formats. @xref{Symbol
1270Attributes,,Symbol Attributes}.
1271@ifclear GENERIC
1272@ifclear MULTI-OBJ
c1253627 1273For the @value{TARGET} target, @command{@value{AS}} is configured to produce
252b5132
RH
1274@value{OBJ-NAME} format object files.
1275@end ifclear
1276@c The following should exhaust all configs that set MULTI-OBJ, ideally
252b5132 1277@ifset I960
a4fb0134 1278On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
252b5132
RH
1279@code{b.out} or COFF format object files.
1280@end ifset
1281@ifset HPPA
a4fb0134 1282On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
252b5132
RH
1283SOM or ELF format object files.
1284@end ifset
1285@end ifclear
1286
1287@node Command Line
1288@section Command Line
1289
1290@cindex command line conventions
0285c67d 1291
a4fb0134 1292After the program name @command{@value{AS}}, the command line may contain
252b5132
RH
1293options and file names. Options may appear in any order, and may be
1294before, after, or between file names. The order of file names is
1295significant.
1296
1297@cindex standard input, as input file
1298@kindex --
1299@file{--} (two hyphens) by itself names the standard input file
a4fb0134 1300explicitly, as one of the files for @command{@value{AS}} to assemble.
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1301
1302@cindex options, command line
1303Except for @samp{--} any command line argument that begins with a
1304hyphen (@samp{-}) is an option. Each option changes the behavior of
a4fb0134 1305@command{@value{AS}}. No option changes the way another option works. An
252b5132
RH
1306option is a @samp{-} followed by one or more letters; the case of
1307the letter is important. All options are optional.
1308
1309Some options expect exactly one file name to follow them. The file
1310name may either immediately follow the option's letter (compatible
1311with older assemblers) or it may be the next command argument (@sc{gnu}
1312standard). These two command lines are equivalent:
1313
1314@smallexample
1315@value{AS} -o my-object-file.o mumble.s
1316@value{AS} -omy-object-file.o mumble.s
1317@end smallexample
1318
1319@node Input Files
1320@section Input Files
1321
1322@cindex input
1323@cindex source program
1324@cindex files, input
1325We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
a4fb0134 1326describe the program input to one run of @command{@value{AS}}. The program may
252b5132
RH
1327be in one or more files; how the source is partitioned into files
1328doesn't change the meaning of the source.
1329
1330@c I added "con" prefix to "catenation" just to prove I can overcome my
1331@c APL training... doc@cygnus.com
1332The source program is a concatenation of the text in all the files, in the
1333order specified.
1334
0285c67d 1335@c man begin DESCRIPTION
a4fb0134 1336Each time you run @command{@value{AS}} it assembles exactly one source
252b5132
RH
1337program. The source program is made up of one or more files.
1338(The standard input is also a file.)
1339
a4fb0134 1340You give @command{@value{AS}} a command line that has zero or more input file
252b5132
RH
1341names. The input files are read (from left file name to right). A
1342command line argument (in any position) that has no special meaning
1343is taken to be an input file name.
1344
a4fb0134
SC
1345If you give @command{@value{AS}} no file names it attempts to read one input file
1346from the @command{@value{AS}} standard input, which is normally your terminal. You
1347may have to type @key{ctl-D} to tell @command{@value{AS}} there is no more program
252b5132
RH
1348to assemble.
1349
1350Use @samp{--} if you need to explicitly name the standard input file
1351in your command line.
1352
a4fb0134 1353If the source is empty, @command{@value{AS}} produces a small, empty object
252b5132
RH
1354file.
1355
0285c67d
NC
1356@c man end
1357
252b5132
RH
1358@subheading Filenames and Line-numbers
1359
1360@cindex input file linenumbers
1361@cindex line numbers, in input files
1362There are two ways of locating a line in the input file (or files) and
1363either may be used in reporting error messages. One way refers to a line
1364number in a physical file; the other refers to a line number in a
1365``logical'' file. @xref{Errors, ,Error and Warning Messages}.
1366
1367@dfn{Physical files} are those files named in the command line given
a4fb0134 1368to @command{@value{AS}}.
252b5132
RH
1369
1370@dfn{Logical files} are simply names declared explicitly by assembler
1371directives; they bear no relation to physical files. Logical file names help
a4fb0134
SC
1372error messages reflect the original source file, when @command{@value{AS}} source
1373is itself synthesized from other files. @command{@value{AS}} understands the
252b5132
RH
1374@samp{#} directives emitted by the @code{@value{GCC}} preprocessor. See also
1375@ref{File,,@code{.file}}.
1376
1377@node Object
1378@section Output (Object) File
1379
1380@cindex object file
1381@cindex output file
1382@kindex a.out
1383@kindex .o
a4fb0134 1384Every time you run @command{@value{AS}} it produces an output file, which is
252b5132
RH
1385your assembly language program translated into numbers. This file
1386is the object file. Its default name is
1387@ifclear BOUT
1388@code{a.out}.
1389@end ifclear
1390@ifset BOUT
1391@ifset GENERIC
1392@code{a.out}, or
1393@end ifset
a4fb0134 1394@code{b.out} when @command{@value{AS}} is configured for the Intel 80960.
252b5132 1395@end ifset
a4fb0134 1396You can give it another name by using the @option{-o} option. Conventionally,
252b5132
RH
1397object file names end with @file{.o}. The default name is used for historical
1398reasons: older assemblers were capable of assembling self-contained programs
1399directly into a runnable program. (For some formats, this isn't currently
1400possible, but it can be done for the @code{a.out} format.)
1401
1402@cindex linker
1403@kindex ld
1404The object file is meant for input to the linker @code{@value{LD}}. It contains
1405assembled program code, information to help @code{@value{LD}} integrate
1406the assembled program into a runnable file, and (optionally) symbolic
1407information for the debugger.
1408
1409@c link above to some info file(s) like the description of a.out.
1410@c don't forget to describe @sc{gnu} info as well as Unix lossage.
1411
1412@node Errors
1413@section Error and Warning Messages
1414
0285c67d
NC
1415@c man begin DESCRIPTION
1416
a349d9dd 1417@cindex error messages
252b5132
RH
1418@cindex warning messages
1419@cindex messages from assembler
a4fb0134 1420@command{@value{AS}} may write warnings and error messages to the standard error
252b5132 1421file (usually your terminal). This should not happen when a compiler
a4fb0134
SC
1422runs @command{@value{AS}} automatically. Warnings report an assumption made so
1423that @command{@value{AS}} could keep assembling a flawed program; errors report a
252b5132
RH
1424grave problem that stops the assembly.
1425
0285c67d
NC
1426@c man end
1427
252b5132
RH
1428@cindex format of warning messages
1429Warning messages have the format
1430
1431@smallexample
1432file_name:@b{NNN}:Warning Message Text
1433@end smallexample
1434
1435@noindent
1436@cindex line numbers, in warnings/errors
1437(where @b{NNN} is a line number). If a logical file name has been given
1438(@pxref{File,,@code{.file}}) it is used for the filename, otherwise the name of
1439the current input file is used. If a logical line number was given
1440@ifset GENERIC
1441(@pxref{Line,,@code{.line}})
1442@end ifset
252b5132
RH
1443then it is used to calculate the number printed,
1444otherwise the actual line in the current source file is printed. The
1445message text is intended to be self explanatory (in the grand Unix
1446tradition).
1447
1448@cindex format of error messages
1449Error messages have the format
1450@smallexample
1451file_name:@b{NNN}:FATAL:Error Message Text
1452@end smallexample
1453The file name and line number are derived as for warning
1454messages. The actual message text may be rather less explanatory
1455because many of them aren't supposed to happen.
1456
1457@node Invoking
1458@chapter Command-Line Options
1459
1460@cindex options, all versions of assembler
1461This chapter describes command-line options available in @emph{all}
1462versions of the @sc{gnu} assembler; @pxref{Machine Dependencies}, for options specific
1463@ifclear GENERIC
c1253627 1464to the @value{TARGET} target.
252b5132
RH
1465@end ifclear
1466@ifset GENERIC
1467to particular machine architectures.
1468@end ifset
1469
0285c67d
NC
1470@c man begin DESCRIPTION
1471
c1253627 1472If you are invoking @command{@value{AS}} via the @sc{gnu} C compiler,
252b5132
RH
1473you can use the @samp{-Wa} option to pass arguments through to the assembler.
1474The assembler arguments must be separated from each other (and the @samp{-Wa})
1475by commas. For example:
1476
1477@smallexample
1478gcc -c -g -O -Wa,-alh,-L file.c
1479@end smallexample
1480
1481@noindent
1482This passes two options to the assembler: @samp{-alh} (emit a listing to
5f5e16be 1483standard output with high-level and assembly source) and @samp{-L} (retain
252b5132
RH
1484local symbols in the symbol table).
1485
1486Usually you do not need to use this @samp{-Wa} mechanism, since many compiler
1487command-line options are automatically passed to the assembler by the compiler.
1488(You can call the @sc{gnu} compiler driver with the @samp{-v} option to see
1489precisely what options it passes to each compilation pass, including the
1490assembler.)
1491
0285c67d
NC
1492@c man end
1493
252b5132
RH
1494@menu
1495* a:: -a[cdhlns] enable listings
caa32fe5 1496* alternate:: --alternate enable alternate macro syntax
252b5132
RH
1497* D:: -D for compatibility
1498* f:: -f to work faster
1499* I:: -I for .include search path
1500@ifclear DIFF-TBL-KLUGE
1501* K:: -K for compatibility
1502@end ifclear
1503@ifset DIFF-TBL-KLUGE
1504* K:: -K for difference tables
1505@end ifset
1506
1507* L:: -L to retain local labels
c3a27914 1508* listing:: --listing-XXX to configure listing output
252b5132
RH
1509* M:: -M or --mri to assemble in MRI compatibility mode
1510* MD:: --MD for dependency tracking
1511* o:: -o to name the object file
1512* R:: -R to join data and text sections
1513* statistics:: --statistics to see statistics about assembly
1514* traditional-format:: --traditional-format for compatible output
1515* v:: -v to announce version
2bdd6cf5 1516* W:: -W, --no-warn, --warn, --fatal-warnings to control warnings
252b5132
RH
1517* Z:: -Z to make object file even after errors
1518@end menu
1519
1520@node a
a4fb0134 1521@section Enable Listings: @option{-a[cdhlns]}
252b5132
RH
1522
1523@kindex -a
1524@kindex -ac
1525@kindex -ad
1526@kindex -ah
1527@kindex -al
1528@kindex -an
1529@kindex -as
1530@cindex listings, enabling
1531@cindex assembly listings, enabling
1532
1533These options enable listing output from the assembler. By itself,
1534@samp{-a} requests high-level, assembly, and symbols listing.
1535You can use other letters to select specific options for the list:
1536@samp{-ah} requests a high-level language listing,
1537@samp{-al} requests an output-program assembly listing, and
1538@samp{-as} requests a symbol table listing.
1539High-level listings require that a compiler debugging option like
1540@samp{-g} be used, and that assembly listings (@samp{-al}) be requested
1541also.
1542
1543Use the @samp{-ac} option to omit false conditionals from a listing. Any lines
1544which are not assembled because of a false @code{.if} (or @code{.ifdef}, or any
1545other conditional), or a true @code{.if} followed by an @code{.else}, will be
1546omitted from the listing.
1547
1548Use the @samp{-ad} option to omit debugging directives from the
1549listing.
1550
1551Once you have specified one of these options, you can further control
1552listing output and its appearance using the directives @code{.list},
1553@code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
1554@code{.sbttl}.
1555The @samp{-an} option turns off all forms processing.
1556If you do not request listing output with one of the @samp{-a} options, the
1557listing-control directives have no effect.
1558
1559The letters after @samp{-a} may be combined into one option,
1560@emph{e.g.}, @samp{-aln}.
1561
c3a27914
NC
1562Note if the assembler source is coming from the standard input (eg because it
1563is being created by @code{@value{GCC}} and the @samp{-pipe} command line switch
1564is being used) then the listing will not contain any comments or preprocessor
1565directives. This is because the listing code buffers input source lines from
1566stdin only after they have been preprocessed by the assembler. This reduces
1567memory usage and makes the code more efficient.
1568
caa32fe5
NC
1569@node alternate
1570@section @option{--alternate}
1571
1572@kindex --alternate
1573Begin in alternate macro mode, see @ref{Altmacro,,@code{.altmacro}}.
1574
252b5132 1575@node D
a4fb0134 1576@section @option{-D}
252b5132
RH
1577
1578@kindex -D
1579This option has no effect whatsoever, but it is accepted to make it more
1580likely that scripts written for other assemblers also work with
a4fb0134 1581@command{@value{AS}}.
252b5132
RH
1582
1583@node f
a4fb0134 1584@section Work Faster: @option{-f}
252b5132
RH
1585
1586@kindex -f
1587@cindex trusted compiler
a4fb0134 1588@cindex faster processing (@option{-f})
252b5132
RH
1589@samp{-f} should only be used when assembling programs written by a
1590(trusted) compiler. @samp{-f} stops the assembler from doing whitespace
1591and comment preprocessing on
1592the input file(s) before assembling them. @xref{Preprocessing,
1593,Preprocessing}.
1594
1595@quotation
1596@emph{Warning:} if you use @samp{-f} when the files actually need to be
a4fb0134 1597preprocessed (if they contain comments, for example), @command{@value{AS}} does
252b5132
RH
1598not work correctly.
1599@end quotation
1600
1601@node I
c1253627 1602@section @code{.include} Search Path: @option{-I} @var{path}
252b5132
RH
1603
1604@kindex -I @var{path}
1605@cindex paths for @code{.include}
1606@cindex search path for @code{.include}
1607@cindex @code{include} directive search path
1608Use this option to add a @var{path} to the list of directories
a4fb0134
SC
1609@command{@value{AS}} searches for files specified in @code{.include}
1610directives (@pxref{Include,,@code{.include}}). You may use @option{-I} as
252b5132 1611many times as necessary to include a variety of paths. The current
a4fb0134 1612working directory is always searched first; after that, @command{@value{AS}}
252b5132
RH
1613searches any @samp{-I} directories in the same order as they were
1614specified (left to right) on the command line.
1615
1616@node K
a4fb0134 1617@section Difference Tables: @option{-K}
252b5132
RH
1618
1619@kindex -K
1620@ifclear DIFF-TBL-KLUGE
1621On the @value{TARGET} family, this option is allowed, but has no effect. It is
1622permitted for compatibility with the @sc{gnu} assembler on other platforms,
1623where it can be used to warn when the assembler alters the machine code
1624generated for @samp{.word} directives in difference tables. The @value{TARGET}
1625family does not have the addressing limitations that sometimes lead to this
1626alteration on other platforms.
1627@end ifclear
1628
1629@ifset DIFF-TBL-KLUGE
1630@cindex difference tables, warning
1631@cindex warning for altered difference tables
a4fb0134 1632@command{@value{AS}} sometimes alters the code emitted for directives of the form
252b5132
RH
1633@samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}.
1634You can use the @samp{-K} option if you want a warning issued when this
1635is done.
1636@end ifset
1637
1638@node L
a4fb0134 1639@section Include Local Labels: @option{-L}
252b5132
RH
1640
1641@kindex -L
1642@cindex local labels, retaining in output
1643Labels beginning with @samp{L} (upper case only) are called @dfn{local
1644labels}. @xref{Symbol Names}. Normally you do not see such labels when
1645debugging, because they are intended for the use of programs (like
1646compilers) that compose assembler programs, not for your notice.
a4fb0134 1647Normally both @command{@value{AS}} and @code{@value{LD}} discard such labels, so you do not
252b5132
RH
1648normally debug with them.
1649
a4fb0134 1650This option tells @command{@value{AS}} to retain those @samp{L@dots{}} symbols
252b5132
RH
1651in the object file. Usually if you do this you also tell the linker
1652@code{@value{LD}} to preserve symbols whose names begin with @samp{L}.
1653
1654By default, a local label is any label beginning with @samp{L}, but each
1655target is allowed to redefine the local label prefix.
1656@ifset HPPA
1657On the HPPA local labels begin with @samp{L$}.
1658@end ifset
252b5132 1659
c3a27914 1660@node listing
a4fb0134 1661@section Configuring listing output: @option{--listing}
c3a27914
NC
1662
1663The listing feature of the assembler can be enabled via the command line switch
1664@samp{-a} (@pxref{a}). This feature combines the input source file(s) with a
1665hex dump of the corresponding locations in the output object file, and displays
1666them as a listing file. The format of this listing can be controlled by pseudo
1667ops inside the assembler source (@pxref{List} @pxref{Title} @pxref{Sbttl}
1668@pxref{Psize} @pxref{Eject}) and also by the following switches:
1669
a4fb0134 1670@table @gcctabopt
c3a27914
NC
1671@item --listing-lhs-width=@samp{number}
1672@kindex --listing-lhs-width
1673@cindex Width of first line disassembly output
1674Sets the maximum width, in words, of the first line of the hex byte dump. This
1675dump appears on the left hand side of the listing output.
1676
1677@item --listing-lhs-width2=@samp{number}
1678@kindex --listing-lhs-width2
1679@cindex Width of continuation lines of disassembly output
1680Sets the maximum width, in words, of any further lines of the hex byte dump for
8dfa0188 1681a given input source line. If this value is not specified, it defaults to being
c3a27914
NC
1682the same as the value specified for @samp{--listing-lhs-width}. If neither
1683switch is used the default is to one.
1684
1685@item --listing-rhs-width=@samp{number}
1686@kindex --listing-rhs-width
1687@cindex Width of source line output
1688Sets the maximum width, in characters, of the source line that is displayed
1689alongside the hex dump. The default value for this parameter is 100. The
1690source line is displayed on the right hand side of the listing output.
1691
1692@item --listing-cont-lines=@samp{number}
1693@kindex --listing-cont-lines
1694@cindex Maximum number of continuation lines
1695Sets the maximum number of continuation lines of hex dump that will be
1696displayed for a given single line of source input. The default value is 4.
1697@end table
1698
252b5132 1699@node M
a4fb0134 1700@section Assemble in MRI Compatibility Mode: @option{-M}
252b5132
RH
1701
1702@kindex -M
1703@cindex MRI compatibility mode
a4fb0134
SC
1704The @option{-M} or @option{--mri} option selects MRI compatibility mode. This
1705changes the syntax and pseudo-op handling of @command{@value{AS}} to make it
252b5132
RH
1706compatible with the @code{ASM68K} or the @code{ASM960} (depending upon the
1707configured target) assembler from Microtec Research. The exact nature of the
1708MRI syntax will not be documented here; see the MRI manuals for more
1709information. Note in particular that the handling of macros and macro
1710arguments is somewhat different. The purpose of this option is to permit
a4fb0134 1711assembling existing MRI assembler code using @command{@value{AS}}.
252b5132
RH
1712
1713The MRI compatibility is not complete. Certain operations of the MRI assembler
1714depend upon its object file format, and can not be supported using other object
1715file formats. Supporting these would require enhancing each object file format
1716individually. These are:
1717
1718@itemize @bullet
1719@item global symbols in common section
1720
1721The m68k MRI assembler supports common sections which are merged by the linker.
a4fb0134 1722Other object file formats do not support this. @command{@value{AS}} handles
252b5132
RH
1723common sections by treating them as a single common symbol. It permits local
1724symbols to be defined within a common section, but it can not support global
1725symbols, since it has no way to describe them.
1726
1727@item complex relocations
1728
1729The MRI assemblers support relocations against a negated section address, and
1730relocations which combine the start addresses of two or more sections. These
1731are not support by other object file formats.
1732
1733@item @code{END} pseudo-op specifying start address
1734
1735The MRI @code{END} pseudo-op permits the specification of a start address.
1736This is not supported by other object file formats. The start address may
a4fb0134 1737instead be specified using the @option{-e} option to the linker, or in a linker
252b5132
RH
1738script.
1739
1740@item @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops
1741
1742The MRI @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops assign a module
1743name to the output file. This is not supported by other object file formats.
1744
1745@item @code{ORG} pseudo-op
1746
1747The m68k MRI @code{ORG} pseudo-op begins an absolute section at a given
a4fb0134 1748address. This differs from the usual @command{@value{AS}} @code{.org} pseudo-op,
252b5132
RH
1749which changes the location within the current section. Absolute sections are
1750not supported by other object file formats. The address of a section may be
1751assigned within a linker script.
1752@end itemize
1753
1754There are some other features of the MRI assembler which are not supported by
a4fb0134 1755@command{@value{AS}}, typically either because they are difficult or because they
252b5132
RH
1756seem of little consequence. Some of these may be supported in future releases.
1757
1758@itemize @bullet
1759
1760@item EBCDIC strings
1761
1762EBCDIC strings are not supported.
1763
1764@item packed binary coded decimal
1765
1766Packed binary coded decimal is not supported. This means that the @code{DC.P}
1767and @code{DCB.P} pseudo-ops are not supported.
1768
1769@item @code{FEQU} pseudo-op
1770
1771The m68k @code{FEQU} pseudo-op is not supported.
1772
1773@item @code{NOOBJ} pseudo-op
1774
1775The m68k @code{NOOBJ} pseudo-op is not supported.
1776
1777@item @code{OPT} branch control options
1778
1779The m68k @code{OPT} branch control options---@code{B}, @code{BRS}, @code{BRB},
a4fb0134 1780@code{BRL}, and @code{BRW}---are ignored. @command{@value{AS}} automatically
252b5132
RH
1781relaxes all branches, whether forward or backward, to an appropriate size, so
1782these options serve no purpose.
1783
1784@item @code{OPT} list control options
1785
1786The following m68k @code{OPT} list control options are ignored: @code{C},
1787@code{CEX}, @code{CL}, @code{CRE}, @code{E}, @code{G}, @code{I}, @code{M},
1788@code{MEX}, @code{MC}, @code{MD}, @code{X}.
1789
1790@item other @code{OPT} options
1791
1792The following m68k @code{OPT} options are ignored: @code{NEST}, @code{O},
1793@code{OLD}, @code{OP}, @code{P}, @code{PCO}, @code{PCR}, @code{PCS}, @code{R}.
1794
1795@item @code{OPT} @code{D} option is default
1796
1797The m68k @code{OPT} @code{D} option is the default, unlike the MRI assembler.
1798@code{OPT NOD} may be used to turn it off.
1799
1800@item @code{XREF} pseudo-op.
1801
1802The m68k @code{XREF} pseudo-op is ignored.
1803
1804@item @code{.debug} pseudo-op
1805
1806The i960 @code{.debug} pseudo-op is not supported.
1807
1808@item @code{.extended} pseudo-op
1809
1810The i960 @code{.extended} pseudo-op is not supported.
1811
1812@item @code{.list} pseudo-op.
1813
1814The various options of the i960 @code{.list} pseudo-op are not supported.
1815
1816@item @code{.optimize} pseudo-op
1817
1818The i960 @code{.optimize} pseudo-op is not supported.
1819
1820@item @code{.output} pseudo-op
1821
1822The i960 @code{.output} pseudo-op is not supported.
1823
1824@item @code{.setreal} pseudo-op
1825
1826The i960 @code{.setreal} pseudo-op is not supported.
1827
1828@end itemize
1829
1830@node MD
c1253627 1831@section Dependency Tracking: @option{--MD}
252b5132
RH
1832
1833@kindex --MD
1834@cindex dependency tracking
1835@cindex make rules
1836
a4fb0134 1837@command{@value{AS}} can generate a dependency file for the file it creates. This
252b5132
RH
1838file consists of a single rule suitable for @code{make} describing the
1839dependencies of the main source file.
1840
1841The rule is written to the file named in its argument.
1842
1843This feature is used in the automatic updating of makefiles.
1844
1845@node o
a4fb0134 1846@section Name the Object File: @option{-o}
252b5132
RH
1847
1848@kindex -o
1849@cindex naming object file
1850@cindex object file name
a4fb0134 1851There is always one object file output when you run @command{@value{AS}}. By
252b5132
RH
1852default it has the name
1853@ifset GENERIC
1854@ifset I960
1855@file{a.out} (or @file{b.out}, for Intel 960 targets only).
1856@end ifset
1857@ifclear I960
1858@file{a.out}.
1859@end ifclear
1860@end ifset
1861@ifclear GENERIC
1862@ifset I960
1863@file{b.out}.
1864@end ifset
1865@ifclear I960
1866@file{a.out}.
1867@end ifclear
1868@end ifclear
1869You use this option (which takes exactly one filename) to give the
1870object file a different name.
1871
a4fb0134 1872Whatever the object file is called, @command{@value{AS}} overwrites any
252b5132
RH
1873existing file of the same name.
1874
1875@node R
a4fb0134 1876@section Join Data and Text Sections: @option{-R}
252b5132
RH
1877
1878@kindex -R
1879@cindex data and text sections, joining
1880@cindex text and data sections, joining
1881@cindex joining text and data sections
1882@cindex merging text and data sections
a4fb0134 1883@option{-R} tells @command{@value{AS}} to write the object file as if all
252b5132
RH
1884data-section data lives in the text section. This is only done at
1885the very last moment: your binary data are the same, but data
1886section parts are relocated differently. The data section part of
1887your object file is zero bytes long because all its bytes are
1888appended to the text section. (@xref{Sections,,Sections and Relocation}.)
1889
a4fb0134 1890When you specify @option{-R} it would be possible to generate shorter
252b5132
RH
1891address displacements (because we do not have to cross between text and
1892data section). We refrain from doing this simply for compatibility with
a4fb0134 1893older versions of @command{@value{AS}}. In future, @option{-R} may work this way.
252b5132 1894
c1253627
NC
1895@ifset COFF-ELF
1896When @command{@value{AS}} is configured for COFF or ELF output,
252b5132
RH
1897this option is only useful if you use sections named @samp{.text} and
1898@samp{.data}.
1899@end ifset
1900
1901@ifset HPPA
a4fb0134
SC
1902@option{-R} is not supported for any of the HPPA targets. Using
1903@option{-R} generates a warning from @command{@value{AS}}.
252b5132
RH
1904@end ifset
1905
1906@node statistics
a4fb0134 1907@section Display Assembly Statistics: @option{--statistics}
252b5132
RH
1908
1909@kindex --statistics
1910@cindex statistics, about assembly
1911@cindex time, total for assembly
1912@cindex space used, maximum for assembly
1913Use @samp{--statistics} to display two statistics about the resources used by
a4fb0134 1914@command{@value{AS}}: the maximum amount of space allocated during the assembly
252b5132
RH
1915(in bytes), and the total execution time taken for the assembly (in @sc{cpu}
1916seconds).
1917
1918@node traditional-format
c1253627 1919@section Compatible Output: @option{--traditional-format}
252b5132
RH
1920
1921@kindex --traditional-format
a4fb0134 1922For some targets, the output of @command{@value{AS}} is different in some ways
252b5132 1923from the output of some existing assembler. This switch requests
a4fb0134 1924@command{@value{AS}} to use the traditional format instead.
252b5132
RH
1925
1926For example, it disables the exception frame optimizations which
a4fb0134 1927@command{@value{AS}} normally does by default on @code{@value{GCC}} output.
252b5132
RH
1928
1929@node v
a4fb0134 1930@section Announce Version: @option{-v}
252b5132
RH
1931
1932@kindex -v
1933@kindex -version
1934@cindex assembler version
1935@cindex version of assembler
1936You can find out what version of as is running by including the
1937option @samp{-v} (which you can also spell as @samp{-version}) on the
1938command line.
1939
1940@node W
a4fb0134 1941@section Control Warnings: @option{-W}, @option{--warn}, @option{--no-warn}, @option{--fatal-warnings}
252b5132 1942
a4fb0134 1943@command{@value{AS}} should never give a warning or error message when
252b5132 1944assembling compiler output. But programs written by people often
a4fb0134 1945cause @command{@value{AS}} to give a warning that a particular assumption was
252b5132 1946made. All such warnings are directed to the standard error file.
2bdd6cf5 1947
c1253627
NC
1948@kindex -W
1949@kindex --no-warn
2bdd6cf5
GK
1950@cindex suppressing warnings
1951@cindex warnings, suppressing
a4fb0134 1952If you use the @option{-W} and @option{--no-warn} options, no warnings are issued.
2bdd6cf5 1953This only affects the warning messages: it does not change any particular of
a4fb0134 1954how @command{@value{AS}} assembles your file. Errors, which stop the assembly,
2bdd6cf5
GK
1955are still reported.
1956
c1253627 1957@kindex --fatal-warnings
2bdd6cf5
GK
1958@cindex errors, caused by warnings
1959@cindex warnings, causing error
a4fb0134 1960If you use the @option{--fatal-warnings} option, @command{@value{AS}} considers
2bdd6cf5
GK
1961files that generate warnings to be in error.
1962
c1253627 1963@kindex --warn
2bdd6cf5 1964@cindex warnings, switching on
a4fb0134 1965You can switch these options off again by specifying @option{--warn}, which
2bdd6cf5 1966causes warnings to be output as usual.
252b5132
RH
1967
1968@node Z
a4fb0134 1969@section Generate Object File in Spite of Errors: @option{-Z}
252b5132
RH
1970@cindex object file, after errors
1971@cindex errors, continuing after
a4fb0134 1972After an error message, @command{@value{AS}} normally produces no output. If for
252b5132 1973some reason you are interested in object file output even after
a4fb0134
SC
1974@command{@value{AS}} gives an error message on your program, use the @samp{-Z}
1975option. If there are any errors, @command{@value{AS}} continues anyways, and
252b5132
RH
1976writes an object file after a final warning message of the form @samp{@var{n}
1977errors, @var{m} warnings, generating bad object file.}
1978
1979@node Syntax
1980@chapter Syntax
1981
1982@cindex machine-independent syntax
1983@cindex syntax, machine-independent
1984This chapter describes the machine-independent syntax allowed in a
a4fb0134 1985source file. @command{@value{AS}} syntax is similar to what many other
252b5132
RH
1986assemblers use; it is inspired by the BSD 4.2
1987@ifclear VAX
1988assembler.
1989@end ifclear
1990@ifset VAX
a4fb0134 1991assembler, except that @command{@value{AS}} does not assemble Vax bit-fields.
252b5132
RH
1992@end ifset
1993
1994@menu
1995* Preprocessing:: Preprocessing
1996* Whitespace:: Whitespace
1997* Comments:: Comments
1998* Symbol Intro:: Symbols
1999* Statements:: Statements
2000* Constants:: Constants
2001@end menu
2002
2003@node Preprocessing
2004@section Preprocessing
2005
2006@cindex preprocessing
a4fb0134 2007The @command{@value{AS}} internal preprocessor:
252b5132
RH
2008@itemize @bullet
2009@cindex whitespace, removed by preprocessor
2010@item
2011adjusts and removes extra whitespace. It leaves one space or tab before
2012the keywords on a line, and turns any other whitespace on the line into
2013a single space.
2014
2015@cindex comments, removed by preprocessor
2016@item
2017removes all comments, replacing them with a single space, or an
2018appropriate number of newlines.
2019
2020@cindex constants, converted by preprocessor
2021@item
2022converts character constants into the appropriate numeric values.
2023@end itemize
2024
2025It does not do macro processing, include file handling, or
2026anything else you may get from your C compiler's preprocessor. You can
2027do include file processing with the @code{.include} directive
2028(@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver
c1253627 2029to get other ``CPP'' style preprocessing by giving the input file a
252b5132
RH
2030@samp{.S} suffix. @xref{Overall Options,, Options Controlling the Kind of
2031Output, gcc.info, Using GNU CC}.
2032
2033Excess whitespace, comments, and character constants
2034cannot be used in the portions of the input text that are not
2035preprocessed.
2036
2037@cindex turning preprocessing on and off
2038@cindex preprocessing, turning on and off
2039@kindex #NO_APP
2040@kindex #APP
2041If the first line of an input file is @code{#NO_APP} or if you use the
2042@samp{-f} option, whitespace and comments are not removed from the input file.
2043Within an input file, you can ask for whitespace and comment removal in
2044specific portions of the by putting a line that says @code{#APP} before the
2045text that may contain whitespace or comments, and putting a line that says
2046@code{#NO_APP} after this text. This feature is mainly intend to support
2047@code{asm} statements in compilers whose output is otherwise free of comments
2048and whitespace.
2049
2050@node Whitespace
2051@section Whitespace
2052
2053@cindex whitespace
2054@dfn{Whitespace} is one or more blanks or tabs, in any order.
2055Whitespace is used to separate symbols, and to make programs neater for
2056people to read. Unless within character constants
2057(@pxref{Characters,,Character Constants}), any whitespace means the same
2058as exactly one space.
2059
2060@node Comments
2061@section Comments
2062
2063@cindex comments
a4fb0134 2064There are two ways of rendering comments to @command{@value{AS}}. In both
252b5132
RH
2065cases the comment is equivalent to one space.
2066
2067Anything from @samp{/*} through the next @samp{*/} is a comment.
2068This means you may not nest these comments.
2069
2070@smallexample
2071/*
2072 The only way to include a newline ('\n') in a comment
2073 is to use this sort of comment.
2074*/
2075
2076/* This sort of comment does not nest. */
2077@end smallexample
2078
2079@cindex line comment character
2080Anything from the @dfn{line comment} character to the next newline
2081is considered a comment and is ignored. The line comment character is
252b5132
RH
2082@ifset ARC
2083@samp{;} on the ARC;
2084@end ifset
550262c4
NC
2085@ifset ARM
2086@samp{@@} on the ARM;
2087@end ifset
252b5132
RH
2088@ifset H8/300
2089@samp{;} for the H8/300 family;
2090@end ifset
252b5132
RH
2091@ifset HPPA
2092@samp{;} for the HPPA;
2093@end ifset
55b62671
AJ
2094@ifset I80386
2095@samp{#} on the i386 and x86-64;
2096@end ifset
252b5132
RH
2097@ifset I960
2098@samp{#} on the i960;
2099@end ifset
e135f41b
NC
2100@ifset PDP11
2101@samp{;} for the PDP-11;
2102@end ifset
041dd5a9
ILT
2103@ifset PJ
2104@samp{;} for picoJava;
2105@end ifset
418c1742 2106@ifset PPC
3fb9d77f 2107@samp{#} for Motorola PowerPC;
418c1742 2108@end ifset
252b5132 2109@ifset SH
ef230218 2110@samp{!} for the Renesas / SuperH SH;
252b5132
RH
2111@end ifset
2112@ifset SPARC
2113@samp{!} on the SPARC;
2114@end ifset
a40cbfa3
NC
2115@ifset IP2K
2116@samp{#} on the ip2k;
2117@end ifset
49f58d10
JB
2118@ifset M32C
2119@samp{#} on the m32c;
2120@end ifset
252b5132
RH
2121@ifset M32R
2122@samp{#} on the m32r;
2123@end ifset
2124@ifset M680X0
2125@samp{|} on the 680x0;
2126@end ifset
60bcf0fa
NC
2127@ifset M68HC11
2128@samp{#} on the 68HC11 and 68HC12;
2129@end ifset
252b5132
RH
2130@ifset VAX
2131@samp{#} on the Vax;
2132@end ifset
2133@ifset Z8000
2134@samp{!} for the Z8000;
2135@end ifset
2136@ifset V850
2137@samp{#} on the V850;
2138@end ifset
e0001a05
NC
2139@ifset XTENSA
2140@samp{#} for Xtensa systems;
2141@end ifset
252b5132 2142see @ref{Machine Dependencies}. @refill
81b0b3f1 2143@c FIXME What about i860?
252b5132
RH
2144
2145@ifset GENERIC
2146On some machines there are two different line comment characters. One
2147character only begins a comment if it is the first non-whitespace character on
2148a line, while the other always begins a comment.
2149@end ifset
2150
2151@ifset V850
2152The V850 assembler also supports a double dash as starting a comment that
2153extends to the end of the line.
2154
2155@samp{--};
2156@end ifset
2157
2158@kindex #
2159@cindex lines starting with @code{#}
2160@cindex logical line numbers
2161To be compatible with past assemblers, lines that begin with @samp{#} have a
2162special interpretation. Following the @samp{#} should be an absolute
2163expression (@pxref{Expressions}): the logical line number of the @emph{next}
2164line. Then a string (@pxref{Strings,, Strings}) is allowed: if present it is a
2165new logical file name. The rest of the line, if any, should be whitespace.
2166
2167If the first non-whitespace characters on the line are not numeric,
2168the line is ignored. (Just like a comment.)
2169
2170@smallexample
2171 # This is an ordinary comment.
2172# 42-6 "new_file_name" # New logical file name
2173 # This is logical line # 36.
2174@end smallexample
2175This feature is deprecated, and may disappear from future versions
a4fb0134 2176of @command{@value{AS}}.
252b5132
RH
2177
2178@node Symbol Intro
2179@section Symbols
2180
2181@cindex characters used in symbols
2182@ifclear SPECIAL-SYMS
2183A @dfn{symbol} is one or more characters chosen from the set of all
2184letters (both upper and lower case), digits and the three characters
2185@samp{_.$}.
2186@end ifclear
2187@ifset SPECIAL-SYMS
2188@ifclear GENERIC
2189@ifset H8
2190A @dfn{symbol} is one or more characters chosen from the set of all
2191letters (both upper and lower case), digits and the three characters
2192@samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in
2193symbol names.)
2194@end ifset
2195@end ifclear
2196@end ifset
2197@ifset GENERIC
2198On most machines, you can also use @code{$} in symbol names; exceptions
2199are noted in @ref{Machine Dependencies}.
2200@end ifset
2201No symbol may begin with a digit. Case is significant.
2202There is no length limit: all characters are significant. Symbols are
2203delimited by characters not in that set, or by the beginning of a file
2204(since the source program must end with a newline, the end of a file is
2205not a possible symbol delimiter). @xref{Symbols}.
2206@cindex length of symbols
2207
2208@node Statements
2209@section Statements
2210
2211@cindex statements, structure of
2212@cindex line separator character
2213@cindex statement separator character
2214@ifclear GENERIC
2215@ifclear abnormal-separator
2216A @dfn{statement} ends at a newline character (@samp{\n}) or at a
2217semicolon (@samp{;}). The newline or semicolon is considered part of
2218the preceding statement. Newlines and semicolons within character
2219constants are an exception: they do not end statements.
2220@end ifclear
2221@ifset abnormal-separator
252b5132
RH
2222@ifset HPPA
2223A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation
2224point (@samp{!}). The newline or exclamation point is considered part of the
2225preceding statement. Newlines and exclamation points within character
2226constants are an exception: they do not end statements.
2227@end ifset
2228@ifset H8
2229A @dfn{statement} ends at a newline character (@samp{\n}); or (for the
7be1c489 2230H8/300) a dollar sign (@samp{$}); or (for the Renesas-SH) a semicolon
252b5132
RH
2231(@samp{;}). The newline or separator character is considered part of
2232the preceding statement. Newlines and separators within character
2233constants are an exception: they do not end statements.
2234@end ifset
2235@end ifset
2236@end ifclear
2237@ifset GENERIC
2238A @dfn{statement} ends at a newline character (@samp{\n}) or line
2239separator character. (The line separator is usually @samp{;}, unless
2240this conflicts with the comment character; @pxref{Machine Dependencies}.) The
2241newline or separator character is considered part of the preceding
2242statement. Newlines and separators within character constants are an
2243exception: they do not end statements.
2244@end ifset
2245
2246@cindex newline, required at file end
2247@cindex EOF, newline must precede
2248It is an error to end any statement with end-of-file: the last
2249character of any input file should be a newline.@refill
2250
2251An empty statement is allowed, and may include whitespace. It is ignored.
2252
2253@cindex instructions and directives
2254@cindex directives and instructions
2255@c "key symbol" is not used elsewhere in the document; seems pedantic to
2256@c @defn{} it in that case, as was done previously... doc@cygnus.com,
2257@c 13feb91.
2258A statement begins with zero or more labels, optionally followed by a
2259key symbol which determines what kind of statement it is. The key
2260symbol determines the syntax of the rest of the statement. If the
2261symbol begins with a dot @samp{.} then the statement is an assembler
2262directive: typically valid for any computer. If the symbol begins with
2263a letter the statement is an assembly language @dfn{instruction}: it
2264assembles into a machine language instruction.
2265@ifset GENERIC
a4fb0134 2266Different versions of @command{@value{AS}} for different computers
252b5132
RH
2267recognize different instructions. In fact, the same symbol may
2268represent a different instruction in a different computer's assembly
2269language.@refill
2270@end ifset
2271
2272@cindex @code{:} (label)
2273@cindex label (@code{:})
2274A label is a symbol immediately followed by a colon (@code{:}).
2275Whitespace before a label or after a colon is permitted, but you may not
2276have whitespace between a label's symbol and its colon. @xref{Labels}.
2277
2278@ifset HPPA
2279For HPPA targets, labels need not be immediately followed by a colon, but
2280the definition of a label must begin in column zero. This also implies that
2281only one label may be defined on each line.
2282@end ifset
2283
2284@smallexample
2285label: .directive followed by something
2286another_label: # This is an empty statement.
2287 instruction operand_1, operand_2, @dots{}
2288@end smallexample
2289
2290@node Constants
2291@section Constants
2292
2293@cindex constants
2294A constant is a number, written so that its value is known by
2295inspection, without knowing any context. Like this:
2296@smallexample
2297@group
2298.byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
2299.ascii "Ring the bell\7" # A string constant.
2300.octa 0x123456789abcdef0123456789ABCDEF0 # A bignum.
2301.float 0f-314159265358979323846264338327\
230295028841971.693993751E-40 # - pi, a flonum.
2303@end group
2304@end smallexample
2305
2306@menu
2307* Characters:: Character Constants
2308* Numbers:: Number Constants
2309@end menu
2310
2311@node Characters
2312@subsection Character Constants
2313
2314@cindex character constants
2315@cindex constants, character
2316There are two kinds of character constants. A @dfn{character} stands
2317for one character in one byte and its value may be used in
2318numeric expressions. String constants (properly called string
2319@emph{literals}) are potentially many bytes and their values may not be
2320used in arithmetic expressions.
2321
2322@menu
2323* Strings:: Strings
2324* Chars:: Characters
2325@end menu
2326
2327@node Strings
2328@subsubsection Strings
2329
2330@cindex string constants
2331@cindex constants, string
2332A @dfn{string} is written between double-quotes. It may contain
2333double-quotes or null characters. The way to get special characters
2334into a string is to @dfn{escape} these characters: precede them with
2335a backslash @samp{\} character. For example @samp{\\} represents
2336one backslash: the first @code{\} is an escape which tells
a4fb0134
SC
2337@command{@value{AS}} to interpret the second character literally as a backslash
2338(which prevents @command{@value{AS}} from recognizing the second @code{\} as an
252b5132
RH
2339escape character). The complete list of escapes follows.
2340
2341@cindex escape codes, character
2342@cindex character escape codes
2343@table @kbd
2344@c @item \a
2345@c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
2346@c
2347@cindex @code{\b} (backspace character)
2348@cindex backspace (@code{\b})
2349@item \b
2350Mnemonic for backspace; for ASCII this is octal code 010.
2351
2352@c @item \e
2353@c Mnemonic for EOText; for ASCII this is octal code 004.
2354@c
2355@cindex @code{\f} (formfeed character)
2356@cindex formfeed (@code{\f})
2357@item \f
2358Mnemonic for FormFeed; for ASCII this is octal code 014.
2359
2360@cindex @code{\n} (newline character)
2361@cindex newline (@code{\n})
2362@item \n
2363Mnemonic for newline; for ASCII this is octal code 012.
2364
2365@c @item \p
2366@c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
2367@c
2368@cindex @code{\r} (carriage return character)
2369@cindex carriage return (@code{\r})
2370@item \r
2371Mnemonic for carriage-Return; for ASCII this is octal code 015.
2372
2373@c @item \s
2374@c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
2375@c other assemblers.
2376@c
2377@cindex @code{\t} (tab)
2378@cindex tab (@code{\t})
2379@item \t
2380Mnemonic for horizontal Tab; for ASCII this is octal code 011.
2381
2382@c @item \v
2383@c Mnemonic for Vertical tab; for ASCII this is octal code 013.
2384@c @item \x @var{digit} @var{digit} @var{digit}
2385@c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
2386@c
2387@cindex @code{\@var{ddd}} (octal character code)
2388@cindex octal character code (@code{\@var{ddd}})
2389@item \ @var{digit} @var{digit} @var{digit}
2390An octal character code. The numeric code is 3 octal digits.
2391For compatibility with other Unix systems, 8 and 9 are accepted as digits:
2392for example, @code{\008} has the value 010, and @code{\009} the value 011.
2393
2394@cindex @code{\@var{xd...}} (hex character code)
2395@cindex hex character code (@code{\@var{xd...}})
2396@item \@code{x} @var{hex-digits...}
2397A hex character code. All trailing hex digits are combined. Either upper or
2398lower case @code{x} works.
2399
2400@cindex @code{\\} (@samp{\} character)
2401@cindex backslash (@code{\\})
2402@item \\
2403Represents one @samp{\} character.
2404
2405@c @item \'
2406@c Represents one @samp{'} (accent acute) character.
2407@c This is needed in single character literals
2408@c (@xref{Characters,,Character Constants}.) to represent
2409@c a @samp{'}.
2410@c
2411@cindex @code{\"} (doublequote character)
2412@cindex doublequote (@code{\"})
2413@item \"
2414Represents one @samp{"} character. Needed in strings to represent
2415this character, because an unescaped @samp{"} would end the string.
2416
2417@item \ @var{anything-else}
2418Any other character when escaped by @kbd{\} gives a warning, but
2419assembles as if the @samp{\} was not present. The idea is that if
2420you used an escape sequence you clearly didn't want the literal
a4fb0134
SC
2421interpretation of the following character. However @command{@value{AS}} has no
2422other interpretation, so @command{@value{AS}} knows it is giving you the wrong
252b5132
RH
2423code and warns you of the fact.
2424@end table
2425
2426Which characters are escapable, and what those escapes represent,
2427varies widely among assemblers. The current set is what we think
2428the BSD 4.2 assembler recognizes, and is a subset of what most C
2429compilers recognize. If you are in doubt, do not use an escape
2430sequence.
2431
2432@node Chars
2433@subsubsection Characters
2434
2435@cindex single character constant
2436@cindex character, single
2437@cindex constant, single character
2438A single character may be written as a single quote immediately
2439followed by that character. The same escapes apply to characters as
2440to strings. So if you want to write the character backslash, you
2441must write @kbd{'\\} where the first @code{\} escapes the second
2442@code{\}. As you can see, the quote is an acute accent, not a
2443grave accent. A newline
2444@ifclear GENERIC
2445@ifclear abnormal-separator
2446(or semicolon @samp{;})
2447@end ifclear
2448@ifset abnormal-separator
252b5132
RH
2449@ifset H8
2450(or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the
7be1c489 2451Renesas SH)
252b5132
RH
2452@end ifset
2453@end ifset
2454@end ifclear
2455immediately following an acute accent is taken as a literal character
2456and does not count as the end of a statement. The value of a character
2457constant in a numeric expression is the machine's byte-wide code for
a4fb0134 2458that character. @command{@value{AS}} assumes your character code is ASCII:
252b5132
RH
2459@kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill
2460
2461@node Numbers
2462@subsection Number Constants
2463
2464@cindex constants, number
2465@cindex number constants
a4fb0134 2466@command{@value{AS}} distinguishes three kinds of numbers according to how they
252b5132
RH
2467are stored in the target machine. @emph{Integers} are numbers that
2468would fit into an @code{int} in the C language. @emph{Bignums} are
2469integers, but they are stored in more than 32 bits. @emph{Flonums}
2470are floating point numbers, described below.
2471
2472@menu
2473* Integers:: Integers
2474* Bignums:: Bignums
2475* Flonums:: Flonums
2476@ifclear GENERIC
2477@ifset I960
2478* Bit Fields:: Bit Fields
2479@end ifset
2480@end ifclear
2481@end menu
2482
2483@node Integers
2484@subsubsection Integers
2485@cindex integers
2486@cindex constants, integer
2487
2488@cindex binary integers
2489@cindex integers, binary
2490A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
2491the binary digits @samp{01}.
2492
2493@cindex octal integers
2494@cindex integers, octal
2495An octal integer is @samp{0} followed by zero or more of the octal
2496digits (@samp{01234567}).
2497
2498@cindex decimal integers
2499@cindex integers, decimal
2500A decimal integer starts with a non-zero digit followed by zero or
2501more digits (@samp{0123456789}).
2502
2503@cindex hexadecimal integers
2504@cindex integers, hexadecimal
2505A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
2506more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
2507
2508Integers have the usual values. To denote a negative integer, use
2509the prefix operator @samp{-} discussed under expressions
2510(@pxref{Prefix Ops,,Prefix Operators}).
2511
2512@node Bignums
2513@subsubsection Bignums
2514
2515@cindex bignums
2516@cindex constants, bignum
2517A @dfn{bignum} has the same syntax and semantics as an integer
2518except that the number (or its negative) takes more than 32 bits to
2519represent in binary. The distinction is made because in some places
2520integers are permitted while bignums are not.
2521
2522@node Flonums
2523@subsubsection Flonums
2524@cindex flonums
2525@cindex floating point numbers
2526@cindex constants, floating point
2527
2528@cindex precision, floating point
2529A @dfn{flonum} represents a floating point number. The translation is
2530indirect: a decimal floating point number from the text is converted by
a4fb0134 2531@command{@value{AS}} to a generic binary floating point number of more than
252b5132
RH
2532sufficient precision. This generic floating point number is converted
2533to a particular computer's floating point format (or formats) by a
a4fb0134 2534portion of @command{@value{AS}} specialized to that computer.
252b5132
RH
2535
2536A flonum is written by writing (in order)
2537@itemize @bullet
2538@item
2539The digit @samp{0}.
2540@ifset HPPA
2541(@samp{0} is optional on the HPPA.)
2542@end ifset
2543
2544@item
a4fb0134 2545A letter, to tell @command{@value{AS}} the rest of the number is a flonum.
252b5132
RH
2546@ifset GENERIC
2547@kbd{e} is recommended. Case is not important.
2548@ignore
2549@c FIXME: verify if flonum syntax really this vague for most cases
2550(Any otherwise illegal letter works here, but that might be changed. Vax BSD
25514.2 assembler seems to allow any of @samp{defghDEFGH}.)
2552@end ignore
2553
7be1c489 2554On the H8/300, Renesas / SuperH SH,
252b5132
RH
2555and AMD 29K architectures, the letter must be
2556one of the letters @samp{DFPRSX} (in upper or lower case).
2557
2558On the ARC, the letter must be one of the letters @samp{DFRS}
2559(in upper or lower case).
2560
2561On the Intel 960 architecture, the letter must be
2562one of the letters @samp{DFT} (in upper or lower case).
2563
2564On the HPPA architecture, the letter must be @samp{E} (upper case only).
2565@end ifset
2566@ifclear GENERIC
252b5132
RH
2567@ifset ARC
2568One of the letters @samp{DFRS} (in upper or lower case).
2569@end ifset
2570@ifset H8
2571One of the letters @samp{DFPRSX} (in upper or lower case).
2572@end ifset
2573@ifset HPPA
2574The letter @samp{E} (upper case only).
2575@end ifset
2576@ifset I960
2577One of the letters @samp{DFT} (in upper or lower case).
2578@end ifset
2579@end ifclear
2580
2581@item
2582An optional sign: either @samp{+} or @samp{-}.
2583
2584@item
2585An optional @dfn{integer part}: zero or more decimal digits.
2586
2587@item
2588An optional @dfn{fractional part}: @samp{.} followed by zero
2589or more decimal digits.
2590
2591@item
2592An optional exponent, consisting of:
2593
2594@itemize @bullet
2595@item
2596An @samp{E} or @samp{e}.
2597@c I can't find a config where "EXP_CHARS" is other than 'eE', but in
2598@c principle this can perfectly well be different on different targets.
2599@item
2600Optional sign: either @samp{+} or @samp{-}.
2601@item
2602One or more decimal digits.
2603@end itemize
2604
2605@end itemize
2606
2607At least one of the integer part or the fractional part must be
2608present. The floating point number has the usual base-10 value.
2609
a4fb0134 2610@command{@value{AS}} does all processing using integers. Flonums are computed
252b5132 2611independently of any floating point hardware in the computer running
a4fb0134 2612@command{@value{AS}}.
252b5132
RH
2613
2614@ifclear GENERIC
2615@ifset I960
2616@c Bit fields are written as a general facility but are also controlled
2617@c by a conditional-compilation flag---which is as of now (21mar91)
2618@c turned on only by the i960 config of GAS.
2619@node Bit Fields
2620@subsubsection Bit Fields
2621
2622@cindex bit fields
2623@cindex constants, bit field
2624You can also define numeric constants as @dfn{bit fields}.
2625specify two numbers separated by a colon---
2626@example
2627@var{mask}:@var{value}
2628@end example
2629@noindent
a4fb0134 2630@command{@value{AS}} applies a bitwise @sc{and} between @var{mask} and
252b5132
RH
2631@var{value}.
2632
2633The resulting number is then packed
2634@ifset GENERIC
2635@c this conditional paren in case bit fields turned on elsewhere than 960
2636(in host-dependent byte order)
2637@end ifset
2638into a field whose width depends on which assembler directive has the
2639bit-field as its argument. Overflow (a result from the bitwise and
2640requiring more binary digits to represent) is not an error; instead,
2641more constants are generated, of the specified width, beginning with the
2642least significant digits.@refill
2643
2644The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long},
2645@code{.short}, and @code{.word} accept bit-field arguments.
2646@end ifset
2647@end ifclear
2648
2649@node Sections
2650@chapter Sections and Relocation
2651@cindex sections
2652@cindex relocation
2653
2654@menu
2655* Secs Background:: Background
2656* Ld Sections:: Linker Sections
2657* As Sections:: Assembler Internal Sections
2658* Sub-Sections:: Sub-Sections
2659* bss:: bss Section
2660@end menu
2661
2662@node Secs Background
2663@section Background
2664
2665Roughly, a section is a range of addresses, with no gaps; all data
2666``in'' those addresses is treated the same for some particular purpose.
2667For example there may be a ``read only'' section.
2668
2669@cindex linker, and assembler
2670@cindex assembler, and linker
2671The linker @code{@value{LD}} reads many object files (partial programs) and
a4fb0134 2672combines their contents to form a runnable program. When @command{@value{AS}}
252b5132
RH
2673emits an object file, the partial program is assumed to start at address 0.
2674@code{@value{LD}} assigns the final addresses for the partial program, so that
2675different partial programs do not overlap. This is actually an
a4fb0134 2676oversimplification, but it suffices to explain how @command{@value{AS}} uses
252b5132
RH
2677sections.
2678
2679@code{@value{LD}} moves blocks of bytes of your program to their run-time
2680addresses. These blocks slide to their run-time addresses as rigid
2681units; their length does not change and neither does the order of bytes
2682within them. Such a rigid unit is called a @emph{section}. Assigning
2683run-time addresses to sections is called @dfn{relocation}. It includes
2684the task of adjusting mentions of object-file addresses so they refer to
2685the proper run-time addresses.
2686@ifset H8
7be1c489 2687For the H8/300, and for the Renesas / SuperH SH,
a4fb0134 2688@command{@value{AS}} pads sections if needed to
252b5132
RH
2689ensure they end on a word (sixteen bit) boundary.
2690@end ifset
2691
2692@cindex standard assembler sections
a4fb0134 2693An object file written by @command{@value{AS}} has at least three sections, any
252b5132
RH
2694of which may be empty. These are named @dfn{text}, @dfn{data} and
2695@dfn{bss} sections.
2696
c1253627 2697@ifset COFF-ELF
252b5132 2698@ifset GENERIC
c1253627 2699When it generates COFF or ELF output,
252b5132 2700@end ifset
a4fb0134 2701@command{@value{AS}} can also generate whatever other named sections you specify
252b5132
RH
2702using the @samp{.section} directive (@pxref{Section,,@code{.section}}).
2703If you do not use any directives that place output in the @samp{.text}
2704or @samp{.data} sections, these sections still exist, but are empty.
2705@end ifset
2706
2707@ifset HPPA
2708@ifset GENERIC
a4fb0134 2709When @command{@value{AS}} generates SOM or ELF output for the HPPA,
252b5132 2710@end ifset
a4fb0134 2711@command{@value{AS}} can also generate whatever other named sections you
252b5132
RH
2712specify using the @samp{.space} and @samp{.subspace} directives. See
2713@cite{HP9000 Series 800 Assembly Language Reference Manual}
2714(HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
2715assembler directives.
2716
2717@ifset SOM
a4fb0134 2718Additionally, @command{@value{AS}} uses different names for the standard
252b5132
RH
2719text, data, and bss sections when generating SOM output. Program text
2720is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
2721BSS into @samp{$BSS$}.
2722@end ifset
2723@end ifset
2724
2725Within the object file, the text section starts at address @code{0}, the
2726data section follows, and the bss section follows the data section.
2727
2728@ifset HPPA
2729When generating either SOM or ELF output files on the HPPA, the text
2730section starts at address @code{0}, the data section at address
2731@code{0x4000000}, and the bss section follows the data section.
2732@end ifset
2733
2734To let @code{@value{LD}} know which data changes when the sections are
a4fb0134 2735relocated, and how to change that data, @command{@value{AS}} also writes to the
252b5132
RH
2736object file details of the relocation needed. To perform relocation
2737@code{@value{LD}} must know, each time an address in the object
2738file is mentioned:
2739@itemize @bullet
2740@item
2741Where in the object file is the beginning of this reference to
2742an address?
2743@item
2744How long (in bytes) is this reference?
2745@item
2746Which section does the address refer to? What is the numeric value of
2747@display
2748(@var{address}) @minus{} (@var{start-address of section})?
2749@end display
2750@item
2751Is the reference to an address ``Program-Counter relative''?
2752@end itemize
2753
2754@cindex addresses, format of
2755@cindex section-relative addressing
a4fb0134 2756In fact, every address @command{@value{AS}} ever uses is expressed as
252b5132
RH
2757@display
2758(@var{section}) + (@var{offset into section})
2759@end display
2760@noindent
a4fb0134 2761Further, most expressions @command{@value{AS}} computes have this section-relative
252b5132
RH
2762nature.
2763@ifset SOM
2764(For some object formats, such as SOM for the HPPA, some expressions are
2765symbol-relative instead.)
2766@end ifset
2767
2768In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset
2769@var{N} into section @var{secname}.''
2770
2771Apart from text, data and bss sections you need to know about the
2772@dfn{absolute} section. When @code{@value{LD}} mixes partial programs,
2773addresses in the absolute section remain unchanged. For example, address
2774@code{@{absolute 0@}} is ``relocated'' to run-time address 0 by
2775@code{@value{LD}}. Although the linker never arranges two partial programs'
2776data sections with overlapping addresses after linking, @emph{by definition}
2777their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one
2778part of a program is always the same address when the program is running as
2779address @code{@{absolute@ 239@}} in any other part of the program.
2780
2781The idea of sections is extended to the @dfn{undefined} section. Any
2782address whose section is unknown at assembly time is by definition
2783rendered @{undefined @var{U}@}---where @var{U} is filled in later.
2784Since numbers are always defined, the only way to generate an undefined
2785address is to mention an undefined symbol. A reference to a named
2786common block would be such a symbol: its value is unknown at assembly
2787time so it has section @emph{undefined}.
2788
2789By analogy the word @emph{section} is used to describe groups of sections in
2790the linked program. @code{@value{LD}} puts all partial programs' text
2791sections in contiguous addresses in the linked program. It is
2792customary to refer to the @emph{text section} of a program, meaning all
2793the addresses of all partial programs' text sections. Likewise for
2794data and bss sections.
2795
2796Some sections are manipulated by @code{@value{LD}}; others are invented for
a4fb0134 2797use of @command{@value{AS}} and have no meaning except during assembly.
252b5132
RH
2798
2799@node Ld Sections
2800@section Linker Sections
2801@code{@value{LD}} deals with just four kinds of sections, summarized below.
2802
2803@table @strong
2804
c1253627 2805@ifset COFF-ELF
252b5132
RH
2806@cindex named sections
2807@cindex sections, named
2808@item named sections
2809@end ifset
2810@ifset aout-bout
2811@cindex text section
2812@cindex data section
2813@itemx text section
2814@itemx data section
2815@end ifset
a4fb0134 2816These sections hold your program. @command{@value{AS}} and @code{@value{LD}} treat them as
252b5132 2817separate but equal sections. Anything you can say of one section is
c1253627
NC
2818true of another.
2819@c @ifset aout-bout
252b5132
RH
2820When the program is running, however, it is
2821customary for the text section to be unalterable. The
2822text section is often shared among processes: it contains
2823instructions, constants and the like. The data section of a running
2824program is usually alterable: for example, C variables would be stored
2825in the data section.
c1253627 2826@c @end ifset
252b5132
RH
2827
2828@cindex bss section
2829@item bss section
2830This section contains zeroed bytes when your program begins running. It
a349d9dd 2831is used to hold uninitialized variables or common storage. The length of
252b5132
RH
2832each partial program's bss section is important, but because it starts
2833out containing zeroed bytes there is no need to store explicit zero
2834bytes in the object file. The bss section was invented to eliminate
2835those explicit zeros from object files.
2836
2837@cindex absolute section
2838@item absolute section
2839Address 0 of this section is always ``relocated'' to runtime address 0.
2840This is useful if you want to refer to an address that @code{@value{LD}} must
2841not change when relocating. In this sense we speak of absolute
2842addresses being ``unrelocatable'': they do not change during relocation.
2843
2844@cindex undefined section
2845@item undefined section
2846This ``section'' is a catch-all for address references to objects not in
2847the preceding sections.
2848@c FIXME: ref to some other doc on obj-file formats could go here.
2849@end table
2850
2851@cindex relocation example
2852An idealized example of three relocatable sections follows.
c1253627 2853@ifset COFF-ELF
252b5132
RH
2854The example uses the traditional section names @samp{.text} and @samp{.data}.
2855@end ifset
2856Memory addresses are on the horizontal axis.
2857
2858@c TEXI2ROFF-KILL
c1253627 2859@ifnottex
252b5132
RH
2860@c END TEXI2ROFF-KILL
2861@smallexample
2862 +-----+----+--+
2863partial program # 1: |ttttt|dddd|00|
2864 +-----+----+--+
2865
2866 text data bss
2867 seg. seg. seg.
2868
2869 +---+---+---+
2870partial program # 2: |TTT|DDD|000|
2871 +---+---+---+
2872
2873 +--+---+-----+--+----+---+-----+~~
2874linked program: | |TTT|ttttt| |dddd|DDD|00000|
2875 +--+---+-----+--+----+---+-----+~~
2876
2877 addresses: 0 @dots{}
2878@end smallexample
2879@c TEXI2ROFF-KILL
c1253627 2880@end ifnottex
252b5132
RH
2881@need 5000
2882@tex
c1253627 2883\bigskip
252b5132
RH
2884\line{\it Partial program \#1: \hfil}
2885\line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2886\line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
2887
2888\line{\it Partial program \#2: \hfil}
2889\line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2890\line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
2891
2892\line{\it linked program: \hfil}
2893\line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
2894\line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
2895ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
2896DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
2897
2898\line{\it addresses: \hfil}
2899\line{0\dots\hfil}
2900
2901@end tex
2902@c END TEXI2ROFF-KILL
2903
2904@node As Sections
2905@section Assembler Internal Sections
2906
2907@cindex internal assembler sections
2908@cindex sections in messages, internal
a4fb0134 2909These sections are meant only for the internal use of @command{@value{AS}}. They
252b5132 2910have no meaning at run-time. You do not really need to know about these
a4fb0134 2911sections for most purposes; but they can be mentioned in @command{@value{AS}}
252b5132 2912warning messages, so it might be helpful to have an idea of their
a4fb0134 2913meanings to @command{@value{AS}}. These sections are used to permit the
252b5132
RH
2914value of every expression in your assembly language program to be a
2915section-relative address.
2916
2917@table @b
2918@cindex assembler internal logic error
2919@item ASSEMBLER-INTERNAL-LOGIC-ERROR!
2920An internal assembler logic error has been found. This means there is a
2921bug in the assembler.
2922
2923@cindex expr (internal section)
2924@item expr section
2925The assembler stores complex expression internally as combinations of
2926symbols. When it needs to represent an expression as a symbol, it puts
2927it in the expr section.
2928@c FIXME item debug
2929@c FIXME item transfer[t] vector preload
2930@c FIXME item transfer[t] vector postload
2931@c FIXME item register
2932@end table
2933
2934@node Sub-Sections
2935@section Sub-Sections
2936
2937@cindex numbered subsections
2938@cindex grouping data
2939@ifset aout-bout
2940Assembled bytes
c1253627 2941@ifset COFF-ELF
252b5132
RH
2942conventionally
2943@end ifset
2944fall into two sections: text and data.
2945@end ifset
2946You may have separate groups of
2947@ifset GENERIC
2948data in named sections
2949@end ifset
2950@ifclear GENERIC
2951@ifclear aout-bout
2952data in named sections
2953@end ifclear
2954@ifset aout-bout
2955text or data
2956@end ifset
2957@end ifclear
2958that you want to end up near to each other in the object file, even though they
a4fb0134 2959are not contiguous in the assembler source. @command{@value{AS}} allows you to
252b5132
RH
2960use @dfn{subsections} for this purpose. Within each section, there can be
2961numbered subsections with values from 0 to 8192. Objects assembled into the
2962same subsection go into the object file together with other objects in the same
2963subsection. For example, a compiler might want to store constants in the text
2964section, but might not want to have them interspersed with the program being
2965assembled. In this case, the compiler could issue a @samp{.text 0} before each
2966section of code being output, and a @samp{.text 1} before each group of
2967constants being output.
2968
2969Subsections are optional. If you do not use subsections, everything
2970goes in subsection number zero.
2971
2972@ifset GENERIC
2973Each subsection is zero-padded up to a multiple of four bytes.
2974(Subsections may be padded a different amount on different flavors
a4fb0134 2975of @command{@value{AS}}.)
252b5132
RH
2976@end ifset
2977@ifclear GENERIC
2978@ifset H8
7be1c489 2979On the H8/300 platform, each subsection is zero-padded to a word
252b5132 2980boundary (two bytes).
c2dcd04e 2981The same is true on the Renesas SH.
252b5132
RH
2982@end ifset
2983@ifset I960
2984@c FIXME section padding (alignment)?
2985@c Rich Pixley says padding here depends on target obj code format; that
2986@c doesn't seem particularly useful to say without further elaboration,
2987@c so for now I say nothing about it. If this is a generic BFD issue,
2988@c these paragraphs might need to vanish from this manual, and be
2989@c discussed in BFD chapter of binutils (or some such).
2990@end ifset
252b5132
RH
2991@end ifclear
2992
2993Subsections appear in your object file in numeric order, lowest numbered
2994to highest. (All this to be compatible with other people's assemblers.)
2995The object file contains no representation of subsections; @code{@value{LD}} and
2996other programs that manipulate object files see no trace of them.
2997They just see all your text subsections as a text section, and all your
2998data subsections as a data section.
2999
3000To specify which subsection you want subsequent statements assembled
3001into, use a numeric argument to specify it, in a @samp{.text
3002@var{expression}} or a @samp{.data @var{expression}} statement.
ed9589d4 3003@ifset COFF
252b5132 3004@ifset GENERIC
ed9589d4 3005When generating COFF output, you
252b5132
RH
3006@end ifset
3007@ifclear GENERIC
3008You
3009@end ifclear
3010can also use an extra subsection
3011argument with arbitrary named sections: @samp{.section @var{name},
3012@var{expression}}.
3013@end ifset
ed9589d4
BW
3014@ifset ELF
3015@ifset GENERIC
3016When generating ELF output, you
3017@end ifset
3018@ifclear GENERIC
3019You
3020@end ifclear
3021can also use the @code{.subsection} directive (@pxref{SubSection})
3022to specify a subsection: @samp{.subsection @var{expression}}.
3023@end ifset
252b5132
RH
3024@var{Expression} should be an absolute expression.
3025(@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0}
3026is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
3027begins in @code{text 0}. For instance:
3028@smallexample
3029.text 0 # The default subsection is text 0 anyway.
3030.ascii "This lives in the first text subsection. *"
3031.text 1
3032.ascii "But this lives in the second text subsection."
3033.data 0
3034.ascii "This lives in the data section,"
3035.ascii "in the first data subsection."
3036.text 0
3037.ascii "This lives in the first text section,"
3038.ascii "immediately following the asterisk (*)."
3039@end smallexample
3040
3041Each section has a @dfn{location counter} incremented by one for every byte
3042assembled into that section. Because subsections are merely a convenience
a4fb0134 3043restricted to @command{@value{AS}} there is no concept of a subsection location
252b5132
RH
3044counter. There is no way to directly manipulate a location counter---but the
3045@code{.align} directive changes it, and any label definition captures its
3046current value. The location counter of the section where statements are being
3047assembled is said to be the @dfn{active} location counter.
3048
3049@node bss
3050@section bss Section
3051
3052@cindex bss section
3053@cindex common variable storage
3054The bss section is used for local common variable storage.
3055You may allocate address space in the bss section, but you may
3056not dictate data to load into it before your program executes. When
3057your program starts running, all the contents of the bss
3058section are zeroed bytes.
3059
3060The @code{.lcomm} pseudo-op defines a symbol in the bss section; see
3061@ref{Lcomm,,@code{.lcomm}}.
3062
3063The @code{.comm} pseudo-op may be used to declare a common symbol, which is
3064another form of uninitialized symbol; see @xref{Comm,,@code{.comm}}.
3065
3066@ifset GENERIC
3067When assembling for a target which supports multiple sections, such as ELF or
3068COFF, you may switch into the @code{.bss} section and define symbols as usual;
3069see @ref{Section,,@code{.section}}. You may only assemble zero values into the
3070section. Typically the section will only contain symbol definitions and
3071@code{.skip} directives (@pxref{Skip,,@code{.skip}}).
3072@end ifset
3073
3074@node Symbols
3075@chapter Symbols
3076
3077@cindex symbols
3078Symbols are a central concept: the programmer uses symbols to name
3079things, the linker uses symbols to link, and the debugger uses symbols
3080to debug.
3081
3082@quotation
3083@cindex debuggers, and symbol order
a4fb0134 3084@emph{Warning:} @command{@value{AS}} does not place symbols in the object file in
252b5132
RH
3085the same order they were declared. This may break some debuggers.
3086@end quotation
3087
3088@menu
3089* Labels:: Labels
3090* Setting Symbols:: Giving Symbols Other Values
3091* Symbol Names:: Symbol Names
3092* Dot:: The Special Dot Symbol
3093* Symbol Attributes:: Symbol Attributes
3094@end menu
3095
3096@node Labels
3097@section Labels
3098
3099@cindex labels
3100A @dfn{label} is written as a symbol immediately followed by a colon
3101@samp{:}. The symbol then represents the current value of the
3102active location counter, and is, for example, a suitable instruction
3103operand. You are warned if you use the same symbol to represent two
3104different locations: the first definition overrides any other
3105definitions.
3106
3107@ifset HPPA
3108On the HPPA, the usual form for a label need not be immediately followed by a
3109colon, but instead must start in column zero. Only one label may be defined on
a4fb0134 3110a single line. To work around this, the HPPA version of @command{@value{AS}} also
252b5132
RH
3111provides a special directive @code{.label} for defining labels more flexibly.
3112@end ifset
3113
3114@node Setting Symbols
3115@section Giving Symbols Other Values
3116
3117@cindex assigning values to symbols
3118@cindex symbol values, assigning
3119A symbol can be given an arbitrary value by writing a symbol, followed
3120by an equals sign @samp{=}, followed by an expression
3121(@pxref{Expressions}). This is equivalent to using the @code{.set}
3122directive. @xref{Set,,@code{.set}}.
3123
3124@node Symbol Names
3125@section Symbol Names
3126
3127@cindex symbol names
3128@cindex names, symbol
3129@ifclear SPECIAL-SYMS
3130Symbol names begin with a letter or with one of @samp{._}. On most
3131machines, you can also use @code{$} in symbol names; exceptions are
3132noted in @ref{Machine Dependencies}. That character may be followed by any
3133string of digits, letters, dollar signs (unless otherwise noted in
3134@ref{Machine Dependencies}), and underscores.
3135@end ifclear
252b5132
RH
3136@ifset SPECIAL-SYMS
3137@ifset H8
3138Symbol names begin with a letter or with one of @samp{._}. On the
7be1c489 3139Renesas SH you can also use @code{$} in symbol names. That
c2dcd04e
NC
3140character may be followed by any string of digits, letters, dollar signs (save
3141on the H8/300), and underscores.
252b5132
RH
3142@end ifset
3143@end ifset
3144
3145Case of letters is significant: @code{foo} is a different symbol name
3146than @code{Foo}.
3147
3148Each symbol has exactly one name. Each name in an assembly language program
3149refers to exactly one symbol. You may use that symbol name any number of times
3150in a program.
3151
3152@subheading Local Symbol Names
3153
3154@cindex local symbol names
3155@cindex symbol names, local
3156@cindex temporary symbol names
3157@cindex symbol names, temporary
3158Local symbols help compilers and programmers use names temporarily.
2d5aaba0
NC
3159They create symbols which are guaranteed to be unique over the entire scope of
3160the input source code and which can be referred to by a simple notation.
3161To define a local symbol, write a label of the form @samp{@b{N}:} (where @b{N}
3162represents any positive integer). To refer to the most recent previous
3163definition of that symbol write @samp{@b{N}b}, using the same number as when
3164you defined the label. To refer to the next definition of a local label, write
3165@samp{@b{N}f}--- The @samp{b} stands for``backwards'' and the @samp{f} stands
3166for ``forwards''.
3167
3168There is no restriction on how you can use these labels, and you can reuse them
3169too. So that it is possible to repeatedly define the same local label (using
3170the same number @samp{@b{N}}), although you can only refer to the most recently
3171defined local label of that number (for a backwards reference) or the next
3172definition of a specific local label for a forward reference. It is also worth
3173noting that the first 10 local labels (@samp{@b{0:}}@dots{}@samp{@b{9:}}) are
3174implemented in a slightly more efficient manner than the others.
3175
3176Here is an example:
3177
3178@smallexample
31791: branch 1f
31802: branch 1b
31811: branch 2f
31822: branch 1b
3183@end smallexample
3184
3185Which is the equivalent of:
3186
3187@smallexample
3188label_1: branch label_3
3189label_2: branch label_1
3190label_3: branch label_4
3191label_4: branch label_3
3192@end smallexample
3193
3194Local symbol names are only a notational device. They are immediately
3195transformed into more conventional symbol names before the assembler uses them.
3196The symbol names stored in the symbol table, appearing in error messages and
3197optionally emitted to the object file. The names are constructed using these
252b5132
RH
3198parts:
3199
3200@table @code
3201@item L
a4fb0134 3202All local labels begin with @samp{L}. Normally both @command{@value{AS}} and
252b5132
RH
3203@code{@value{LD}} forget symbols that start with @samp{L}. These labels are
3204used for symbols you are never intended to see. If you use the
a4fb0134 3205@samp{-L} option then @command{@value{AS}} retains these symbols in the
252b5132
RH
3206object file. If you also instruct @code{@value{LD}} to retain these symbols,
3207you may use them in debugging.
3208
2d5aaba0
NC
3209@item @var{number}
3210This is the number that was used in the local label definition. So if the
3211label is written @samp{55:} then the number is @samp{55}.
252b5132 3212
2d5aaba0
NC
3213@item @kbd{C-B}
3214This unusual character is included so you do not accidentally invent a symbol
3215of the same name. The character has ASCII value of @samp{\002} (control-B).
252b5132
RH
3216
3217@item @emph{ordinal number}
2d5aaba0
NC
3218This is a serial number to keep the labels distinct. The first definition of
3219@samp{0:} gets the number @samp{1}. The 15th definition of @samp{0:} gets the
3220number @samp{15}, and so on. Likewise the first definition of @samp{1:} gets
3221the number @samp{1} and its 15th defintion gets @samp{15} as well.
252b5132
RH
3222@end table
3223
2d5aaba0
NC
3224So for example, the first @code{1:} is named @code{L1@kbd{C-B}1}, the 44th
3225@code{3:} is named @code{L3@kbd{C-B}44}.
3226
3227@subheading Dollar Local Labels
3228@cindex dollar local symbols
3229
3230@code{@value{AS}} also supports an even more local form of local labels called
3231dollar labels. These labels go out of scope (ie they become undefined) as soon
3232as a non-local label is defined. Thus they remain valid for only a small
3233region of the input source code. Normal local labels, by contrast, remain in
3234scope for the entire file, or until they are redefined by another occurrence of
3235the same local label.
3236
3237Dollar labels are defined in exactly the same way as ordinary local labels,
3238except that instead of being terminated by a colon, they are terminated by a
3239dollar sign. eg @samp{@b{55$}}.
3240
3241They can also be distinguished from ordinary local labels by their transformed
3242name which uses ASCII character @samp{\001} (control-A) as the magic character
3243to distinguish them from ordinary labels. Thus the 5th defintion of @samp{6$}
3244is named @samp{L6@kbd{C-A}5}.
252b5132
RH
3245
3246@node Dot
3247@section The Special Dot Symbol
3248
3249@cindex dot (symbol)
3250@cindex @code{.} (symbol)
3251@cindex current address
3252@cindex location counter
3253The special symbol @samp{.} refers to the current address that
a4fb0134 3254@command{@value{AS}} is assembling into. Thus, the expression @samp{melvin:
252b5132
RH
3255.long .} defines @code{melvin} to contain its own address.
3256Assigning a value to @code{.} is treated the same as a @code{.org}
3257directive. Thus, the expression @samp{.=.+4} is the same as saying
3258@ifclear no-space-dir
3259@samp{.space 4}.
3260@end ifclear
252b5132
RH
3261
3262@node Symbol Attributes
3263@section Symbol Attributes
3264
3265@cindex symbol attributes
3266@cindex attributes, symbol
3267Every symbol has, as well as its name, the attributes ``Value'' and
3268``Type''. Depending on output format, symbols can also have auxiliary
3269attributes.
3270@ifset INTERNALS
3271The detailed definitions are in @file{a.out.h}.
3272@end ifset
3273
a4fb0134 3274If you use a symbol without defining it, @command{@value{AS}} assumes zero for
252b5132
RH
3275all these attributes, and probably won't warn you. This makes the
3276symbol an externally defined symbol, which is generally what you
3277would want.
3278
3279@menu
3280* Symbol Value:: Value
3281* Symbol Type:: Type
3282@ifset aout-bout
3283@ifset GENERIC
3284* a.out Symbols:: Symbol Attributes: @code{a.out}
3285@end ifset
3286@ifclear GENERIC
3287@ifclear BOUT
3288* a.out Symbols:: Symbol Attributes: @code{a.out}
3289@end ifclear
3290@ifset BOUT
3291* a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out}
3292@end ifset
3293@end ifclear
3294@end ifset
3295@ifset COFF
3296* COFF Symbols:: Symbol Attributes for COFF
3297@end ifset
3298@ifset SOM
3299* SOM Symbols:: Symbol Attributes for SOM
3300@end ifset
3301@end menu
3302
3303@node Symbol Value
3304@subsection Value
3305
3306@cindex value of a symbol
3307@cindex symbol value
3308The value of a symbol is (usually) 32 bits. For a symbol which labels a
3309location in the text, data, bss or absolute sections the value is the
3310number of addresses from the start of that section to the label.
3311Naturally for text, data and bss sections the value of a symbol changes
3312as @code{@value{LD}} changes section base addresses during linking. Absolute
3313symbols' values do not change during linking: that is why they are
3314called absolute.
3315
3316The value of an undefined symbol is treated in a special way. If it is
33170 then the symbol is not defined in this assembler source file, and
3318@code{@value{LD}} tries to determine its value from other files linked into the
3319same program. You make this kind of symbol simply by mentioning a symbol
3320name without defining it. A non-zero value represents a @code{.comm}
3321common declaration. The value is how much common storage to reserve, in
3322bytes (addresses). The symbol refers to the first address of the
3323allocated storage.
3324
3325@node Symbol Type
3326@subsection Type
3327
3328@cindex type of a symbol
3329@cindex symbol type
3330The type attribute of a symbol contains relocation (section)
3331information, any flag settings indicating that a symbol is external, and
3332(optionally), other information for linkers and debuggers. The exact
3333format depends on the object-code output format in use.
3334
3335@ifset aout-bout
3336@ifclear GENERIC
3337@ifset BOUT
3338@c The following avoids a "widow" subsection title. @group would be
3339@c better if it were available outside examples.
3340@need 1000
3341@node a.out Symbols
3342@subsection Symbol Attributes: @code{a.out}, @code{b.out}
3343
3344@cindex @code{b.out} symbol attributes
3345@cindex symbol attributes, @code{b.out}
a4fb0134 3346These symbol attributes appear only when @command{@value{AS}} is configured for
252b5132
RH
3347one of the Berkeley-descended object output formats---@code{a.out} or
3348@code{b.out}.
3349
3350@end ifset
3351@ifclear BOUT
3352@node a.out Symbols
3353@subsection Symbol Attributes: @code{a.out}
3354
3355@cindex @code{a.out} symbol attributes
3356@cindex symbol attributes, @code{a.out}
3357
3358@end ifclear
3359@end ifclear
3360@ifset GENERIC
3361@node a.out Symbols
3362@subsection Symbol Attributes: @code{a.out}
3363
3364@cindex @code{a.out} symbol attributes
3365@cindex symbol attributes, @code{a.out}
3366
3367@end ifset
3368@menu
3369* Symbol Desc:: Descriptor
3370* Symbol Other:: Other
3371@end menu
3372
3373@node Symbol Desc
3374@subsubsection Descriptor
3375
3376@cindex descriptor, of @code{a.out} symbol
3377This is an arbitrary 16-bit value. You may establish a symbol's
3378descriptor value by using a @code{.desc} statement
3379(@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
a4fb0134 3380@command{@value{AS}}.
252b5132
RH
3381
3382@node Symbol Other
3383@subsubsection Other
3384
3385@cindex other attribute, of @code{a.out} symbol
a4fb0134 3386This is an arbitrary 8-bit value. It means nothing to @command{@value{AS}}.
252b5132
RH
3387@end ifset
3388
3389@ifset COFF
3390@node COFF Symbols
3391@subsection Symbol Attributes for COFF
3392
3393@cindex COFF symbol attributes
3394@cindex symbol attributes, COFF
3395
3396The COFF format supports a multitude of auxiliary symbol attributes;
3397like the primary symbol attributes, they are set between @code{.def} and
3398@code{.endef} directives.
3399
3400@subsubsection Primary Attributes
3401
3402@cindex primary attributes, COFF symbols
3403The symbol name is set with @code{.def}; the value and type,
3404respectively, with @code{.val} and @code{.type}.
3405
3406@subsubsection Auxiliary Attributes
3407
3408@cindex auxiliary attributes, COFF symbols
a4fb0134 3409The @command{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
c87db184
CF
3410@code{.size}, @code{.tag}, and @code{.weak} can generate auxiliary symbol
3411table information for COFF.
252b5132
RH
3412@end ifset
3413
3414@ifset SOM
3415@node SOM Symbols
3416@subsection Symbol Attributes for SOM
3417
3418@cindex SOM symbol attributes
3419@cindex symbol attributes, SOM
3420
3421The SOM format for the HPPA supports a multitude of symbol attributes set with
3422the @code{.EXPORT} and @code{.IMPORT} directives.
3423
3424The attributes are described in @cite{HP9000 Series 800 Assembly
3425Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
3426@code{EXPORT} assembler directive documentation.
3427@end ifset
3428
3429@node Expressions
3430@chapter Expressions
3431
3432@cindex expressions
3433@cindex addresses
3434@cindex numeric values
3435An @dfn{expression} specifies an address or numeric value.
3436Whitespace may precede and/or follow an expression.
3437
3438The result of an expression must be an absolute number, or else an offset into
3439a particular section. If an expression is not absolute, and there is not
a4fb0134 3440enough information when @command{@value{AS}} sees the expression to know its
252b5132
RH
3441section, a second pass over the source program might be necessary to interpret
3442the expression---but the second pass is currently not implemented.
a4fb0134 3443@command{@value{AS}} aborts with an error message in this situation.
252b5132
RH
3444
3445@menu
3446* Empty Exprs:: Empty Expressions
3447* Integer Exprs:: Integer Expressions
3448@end menu
3449
3450@node Empty Exprs
3451@section Empty Expressions
3452
3453@cindex empty expressions
3454@cindex expressions, empty
3455An empty expression has no value: it is just whitespace or null.
3456Wherever an absolute expression is required, you may omit the
a4fb0134 3457expression, and @command{@value{AS}} assumes a value of (absolute) 0. This
252b5132
RH
3458is compatible with other assemblers.
3459
3460@node Integer Exprs
3461@section Integer Expressions
3462
3463@cindex integer expressions
3464@cindex expressions, integer
3465An @dfn{integer expression} is one or more @emph{arguments} delimited
3466by @emph{operators}.
3467
3468@menu
3469* Arguments:: Arguments
3470* Operators:: Operators
3471* Prefix Ops:: Prefix Operators
3472* Infix Ops:: Infix Operators
3473@end menu
3474
3475@node Arguments
3476@subsection Arguments
3477
3478@cindex expression arguments
3479@cindex arguments in expressions
3480@cindex operands in expressions
3481@cindex arithmetic operands
3482@dfn{Arguments} are symbols, numbers or subexpressions. In other
3483contexts arguments are sometimes called ``arithmetic operands''. In
3484this manual, to avoid confusing them with the ``instruction operands'' of
3485the machine language, we use the term ``argument'' to refer to parts of
3486expressions only, reserving the word ``operand'' to refer only to machine
3487instruction operands.
3488
3489Symbols are evaluated to yield @{@var{section} @var{NNN}@} where
3490@var{section} is one of text, data, bss, absolute,
3491or undefined. @var{NNN} is a signed, 2's complement 32 bit
3492integer.
3493
3494Numbers are usually integers.
3495
3496A number can be a flonum or bignum. In this case, you are warned
a4fb0134 3497that only the low order 32 bits are used, and @command{@value{AS}} pretends
252b5132
RH
3498these 32 bits are an integer. You may write integer-manipulating
3499instructions that act on exotic constants, compatible with other
3500assemblers.
3501
3502@cindex subexpressions
3503Subexpressions are a left parenthesis @samp{(} followed by an integer
3504expression, followed by a right parenthesis @samp{)}; or a prefix
3505operator followed by an argument.
3506
3507@node Operators
3508@subsection Operators
3509
3510@cindex operators, in expressions
3511@cindex arithmetic functions
3512@cindex functions, in expressions
3513@dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
3514operators are followed by an argument. Infix operators appear
3515between their arguments. Operators may be preceded and/or followed by
3516whitespace.
3517
3518@node Prefix Ops
3519@subsection Prefix Operator
3520
3521@cindex prefix operators
a4fb0134 3522@command{@value{AS}} has the following @dfn{prefix operators}. They each take
252b5132
RH
3523one argument, which must be absolute.
3524
3525@c the tex/end tex stuff surrounding this small table is meant to make
3526@c it align, on the printed page, with the similar table in the next
3527@c section (which is inside an enumerate).
3528@tex
3529\global\advance\leftskip by \itemindent
3530@end tex
3531
3532@table @code
3533@item -
3534@dfn{Negation}. Two's complement negation.
3535@item ~
3536@dfn{Complementation}. Bitwise not.
3537@end table
3538
3539@tex
3540\global\advance\leftskip by -\itemindent
3541@end tex
3542
3543@node Infix Ops
3544@subsection Infix Operators
3545
3546@cindex infix operators
3547@cindex operators, permitted arguments
3548@dfn{Infix operators} take two arguments, one on either side. Operators
3549have precedence, but operations with equal precedence are performed left
a4fb0134 3550to right. Apart from @code{+} or @option{-}, both arguments must be
252b5132
RH
3551absolute, and the result is absolute.
3552
3553@enumerate
3554@cindex operator precedence
3555@cindex precedence of operators
3556
3557@item
3558Highest Precedence
3559
3560@table @code
3561@item *
3562@dfn{Multiplication}.
3563
3564@item /
3565@dfn{Division}. Truncation is the same as the C operator @samp{/}
3566
3567@item %
3568@dfn{Remainder}.
3569
d1eac9d9 3570@item <<
252b5132
RH
3571@dfn{Shift Left}. Same as the C operator @samp{<<}.
3572
d1eac9d9 3573@item >>
252b5132
RH
3574@dfn{Shift Right}. Same as the C operator @samp{>>}.
3575@end table
3576
3577@item
3578Intermediate precedence
3579
3580@table @code
3581@item |
3582
3583@dfn{Bitwise Inclusive Or}.
3584
3585@item &
3586@dfn{Bitwise And}.
3587
3588@item ^
3589@dfn{Bitwise Exclusive Or}.
3590
3591@item !
3592@dfn{Bitwise Or Not}.
3593@end table
3594
3595@item
b131d4dc 3596Low Precedence
252b5132
RH
3597
3598@table @code
3599@cindex addition, permitted arguments
3600@cindex plus, permitted arguments
3601@cindex arguments for addition
3602@item +
3603@dfn{Addition}. If either argument is absolute, the result has the section of
3604the other argument. You may not add together arguments from different
3605sections.
3606
3607@cindex subtraction, permitted arguments
3608@cindex minus, permitted arguments
3609@cindex arguments for subtraction
3610@item -
3611@dfn{Subtraction}. If the right argument is absolute, the
3612result has the section of the left argument.
3613If both arguments are in the same section, the result is absolute.
3614You may not subtract arguments from different sections.
3615@c FIXME is there still something useful to say about undefined - undefined ?
b131d4dc
NC
3616
3617@cindex comparison expressions
3618@cindex expressions, comparison
3619@item ==
3620@dfn{Is Equal To}
3621@item <>
723a8472 3622@itemx !=
b131d4dc
NC
3623@dfn{Is Not Equal To}
3624@item <
3625@dfn{Is Less Than}
d1eac9d9 3626@item >
b131d4dc 3627@dfn{Is Greater Than}
d1eac9d9 3628@item >=
b131d4dc 3629@dfn{Is Greater Than Or Equal To}
d1eac9d9 3630@item <=
b131d4dc
NC
3631@dfn{Is Less Than Or Equal To}
3632
3633The comparison operators can be used as infix operators. A true results has a
3634value of -1 whereas a false result has a value of 0. Note, these operators
3635perform signed comparisons.
3636@end table
3637
3638@item Lowest Precedence
3639
3640@table @code
3641@item &&
3642@dfn{Logical And}.
3643
3644@item ||
3645@dfn{Logical Or}.
3646
3647These two logical operations can be used to combine the results of sub
3648expressions. Note, unlike the comparison operators a true result returns a
3649value of 1 but a false results does still return 0. Also note that the logical
3650or operator has a slightly lower precedence than logical and.
3651
252b5132
RH
3652@end table
3653@end enumerate
3654
3655In short, it's only meaningful to add or subtract the @emph{offsets} in an
3656address; you can only have a defined section in one of the two arguments.
3657
3658@node Pseudo Ops
3659@chapter Assembler Directives
3660
3661@cindex directives, machine independent
3662@cindex pseudo-ops, machine independent
3663@cindex machine independent directives
3664All assembler directives have names that begin with a period (@samp{.}).
3665The rest of the name is letters, usually in lower case.
3666
3667This chapter discusses directives that are available regardless of the
3668target machine configuration for the @sc{gnu} assembler.
3669@ifset GENERIC
3670Some machine configurations provide additional directives.
3671@xref{Machine Dependencies}.
3672@end ifset
3673@ifclear GENERIC
3674@ifset machine-directives
3675@xref{Machine Dependencies} for additional directives.
3676@end ifset
3677@end ifclear
3678
3679@menu
3680* Abort:: @code{.abort}
3681@ifset COFF
3682* ABORT:: @code{.ABORT}
3683@end ifset
f0dc282c 3684
252b5132 3685* Align:: @code{.align @var{abs-expr} , @var{abs-expr}}
caa32fe5 3686* Altmacro:: @code{.altmacro}
252b5132
RH
3687* Ascii:: @code{.ascii "@var{string}"}@dots{}
3688* Asciz:: @code{.asciz "@var{string}"}@dots{}
3689* Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}}
3690* Byte:: @code{.byte @var{expressions}}
3691* Comm:: @code{.comm @var{symbol} , @var{length} }
54cfded0 3692
cdfbf930 3693* CFI directives:: @code{.cfi_startproc}, @code{.cfi_endproc}, etc.
54cfded0 3694
252b5132
RH
3695* Data:: @code{.data @var{subsection}}
3696@ifset COFF
3697* Def:: @code{.def @var{name}}
3698@end ifset
3699@ifset aout-bout
3700* Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
3701@end ifset
3702@ifset COFF
3703* Dim:: @code{.dim}
3704@end ifset
f0dc282c 3705
252b5132
RH
3706* Double:: @code{.double @var{flonums}}
3707* Eject:: @code{.eject}
3708* Else:: @code{.else}
3fd9f047 3709* Elseif:: @code{.elseif}
252b5132
RH
3710* End:: @code{.end}
3711@ifset COFF
3712* Endef:: @code{.endef}
3713@end ifset
f0dc282c 3714
252b5132
RH
3715* Endfunc:: @code{.endfunc}
3716* Endif:: @code{.endif}
3717* Equ:: @code{.equ @var{symbol}, @var{expression}}
3718* Equiv:: @code{.equiv @var{symbol}, @var{expression}}
3719* Err:: @code{.err}
d190d046 3720* Error:: @code{.error @var{string}}
252b5132
RH
3721* Exitm:: @code{.exitm}
3722* Extern:: @code{.extern}
3723* Fail:: @code{.fail}
3724@ifclear no-file-dir
3725* File:: @code{.file @var{string}}
3726@end ifclear
f0dc282c 3727
252b5132
RH
3728* Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}}
3729* Float:: @code{.float @var{flonums}}
3730* Func:: @code{.func}
3731* Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}}
c91d2e08
NC
3732@ifset ELF
3733* Hidden:: @code{.hidden @var{names}}
3734@end ifset
f0dc282c 3735
252b5132
RH
3736* hword:: @code{.hword @var{expressions}}
3737* Ident:: @code{.ident}
3738* If:: @code{.if @var{absolute expression}}
7e005732 3739* Incbin:: @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
252b5132
RH
3740* Include:: @code{.include "@var{file}"}
3741* Int:: @code{.int @var{expressions}}
c91d2e08
NC
3742@ifset ELF
3743* Internal:: @code{.internal @var{names}}
3744@end ifset
f0dc282c 3745
252b5132
RH
3746* Irp:: @code{.irp @var{symbol},@var{values}}@dots{}
3747* Irpc:: @code{.irpc @var{symbol},@var{values}}@dots{}
3748* Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
3749* Lflags:: @code{.lflags}
3750@ifclear no-line-dir
3751* Line:: @code{.line @var{line-number}}
3752@end ifclear
f0dc282c 3753
252b5132
RH
3754* Linkonce:: @code{.linkonce [@var{type}]}
3755* List:: @code{.list}
bd0eb99b
RH
3756* Ln:: @code{.ln @var{line-number}}
3757
3758* LNS directives:: @code{.file}, @code{.loc}, etc.
3759
252b5132
RH
3760* Long:: @code{.long @var{expressions}}
3761@ignore
3762* Lsym:: @code{.lsym @var{symbol}, @var{expression}}
3763@end ignore
f0dc282c 3764
252b5132
RH
3765* Macro:: @code{.macro @var{name} @var{args}}@dots{}
3766* MRI:: @code{.mri @var{val}}
caa32fe5 3767* Noaltmacro:: @code{.noaltmacro}
252b5132
RH
3768* Nolist:: @code{.nolist}
3769* Octa:: @code{.octa @var{bignums}}
3770* Org:: @code{.org @var{new-lc} , @var{fill}}
3771* P2align:: @code{.p2align @var{abs-expr} , @var{abs-expr}}
c91d2e08
NC
3772@ifset ELF
3773* PopSection:: @code{.popsection}
3774* Previous:: @code{.previous}
3775@end ifset
f0dc282c 3776
252b5132 3777* Print:: @code{.print @var{string}}
c91d2e08
NC
3778@ifset ELF
3779* Protected:: @code{.protected @var{names}}
3780@end ifset
f0dc282c 3781
252b5132
RH
3782* Psize:: @code{.psize @var{lines}, @var{columns}}
3783* Purgem:: @code{.purgem @var{name}}
c91d2e08
NC
3784@ifset ELF
3785* PushSection:: @code{.pushsection @var{name}}
3786@end ifset
f0dc282c 3787
252b5132
RH
3788* Quad:: @code{.quad @var{bignums}}
3789* Rept:: @code{.rept @var{count}}
3790* Sbttl:: @code{.sbttl "@var{subheading}"}
3791@ifset COFF
3792* Scl:: @code{.scl @var{class}}
c1253627
NC
3793@end ifset
3794@ifset COFF-ELF
3795* Section:: @code{.section @var{name}}
252b5132 3796@end ifset
f0dc282c 3797
252b5132
RH
3798* Set:: @code{.set @var{symbol}, @var{expression}}
3799* Short:: @code{.short @var{expressions}}
3800* Single:: @code{.single @var{flonums}}
c1253627 3801@ifset COFF-ELF
c91d2e08 3802* Size:: @code{.size [@var{name} , @var{expression}]}
c1253627
NC
3803@end ifset
3804
252b5132
RH
3805* Skip:: @code{.skip @var{size} , @var{fill}}
3806* Sleb128:: @code{.sleb128 @var{expressions}}
3807* Space:: @code{.space @var{size} , @var{fill}}
3808@ifset have-stabs
3809* Stab:: @code{.stabd, .stabn, .stabs}
3810@end ifset
f0dc282c 3811
252b5132
RH
3812* String:: @code{.string "@var{str}"}
3813* Struct:: @code{.struct @var{expression}}
3814@ifset ELF
c91d2e08 3815* SubSection:: @code{.subsection}
252b5132
RH
3816* Symver:: @code{.symver @var{name},@var{name2@@nodename}}
3817@end ifset
f0dc282c 3818
252b5132
RH
3819@ifset COFF
3820* Tag:: @code{.tag @var{structname}}
3821@end ifset
f0dc282c 3822
252b5132
RH
3823* Text:: @code{.text @var{subsection}}
3824* Title:: @code{.title "@var{heading}"}
c1253627 3825@ifset COFF-ELF
c91d2e08 3826* Type:: @code{.type <@var{int} | @var{name} , @var{type description}>}
c1253627
NC
3827@end ifset
3828
c91d2e08 3829* Uleb128:: @code{.uleb128 @var{expressions}}
252b5132 3830@ifset COFF
252b5132
RH
3831* Val:: @code{.val @var{addr}}
3832@end ifset
f0dc282c 3833
2e13b764 3834@ifset ELF
c91d2e08 3835* Version:: @code{.version "@var{string}"}
c91d2e08
NC
3836* VTableEntry:: @code{.vtable_entry @var{table}, @var{offset}}
3837* VTableInherit:: @code{.vtable_inherit @var{child}, @var{parent}}
2e13b764 3838@end ifset
f0dc282c 3839
d190d046 3840* Warning:: @code{.warning @var{string}}
c87db184 3841* Weak:: @code{.weak @var{names}}
252b5132
RH
3842* Word:: @code{.word @var{expressions}}
3843* Deprecated:: Deprecated Directives
3844@end menu
3845
3846@node Abort
3847@section @code{.abort}
3848
3849@cindex @code{abort} directive
3850@cindex stopping the assembly
3851This directive stops the assembly immediately. It is for
3852compatibility with other assemblers. The original idea was that the
3853assembly language source would be piped into the assembler. If the sender
a4fb0134 3854of the source quit, it could use this directive tells @command{@value{AS}} to
252b5132
RH
3855quit also. One day @code{.abort} will not be supported.
3856
3857@ifset COFF
3858@node ABORT
3859@section @code{.ABORT}
3860
3861@cindex @code{ABORT} directive
a4fb0134 3862When producing COFF output, @command{@value{AS}} accepts this directive as a
252b5132
RH
3863synonym for @samp{.abort}.
3864
3865@ifset BOUT
a4fb0134 3866When producing @code{b.out} output, @command{@value{AS}} accepts this directive,
252b5132
RH
3867but ignores it.
3868@end ifset
3869@end ifset
3870
3871@node Align
3872@section @code{.align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3873
3874@cindex padding the location counter
3875@cindex @code{align} directive
3876Pad the location counter (in the current subsection) to a particular storage
3877boundary. The first expression (which must be absolute) is the alignment
3878required, as described below.
3879
3880The second expression (also absolute) gives the fill value to be stored in the
3881padding bytes. It (and the comma) may be omitted. If it is omitted, the
3882padding bytes are normally zero. However, on some systems, if the section is
3883marked as containing code and the fill value is omitted, the space is filled
3884with no-op instructions.
3885
3886The third expression is also absolute, and is also optional. If it is present,
3887it is the maximum number of bytes that should be skipped by this alignment
3888directive. If doing the alignment would require skipping more bytes than the
3889specified maximum, then the alignment is not done at all. You can omit the
3890fill value (the second argument) entirely by simply using two commas after the
3891required alignment; this can be useful if you want the alignment to be filled
3892with no-op instructions when appropriate.
3893
3894The way the required alignment is specified varies from system to system.
7be1c489 3895For the arc, hppa, i386 using ELF, i860, iq2000, m68k, or32,
60946ad0 3896s390, sparc, tic4x, tic80 and xtensa, the first expression is the
252b5132
RH
3897alignment request in bytes. For example @samp{.align 8} advances
3898the location counter until it is a multiple of 8. If the location counter
60946ad0
AM
3899is already a multiple of 8, no change is needed. For the tic54x, the
3900first expression is the alignment request in words.
252b5132 3901
adcf07e6
NC
3902For other systems, including the i386 using a.out format, and the arm and
3903strongarm, it is the
252b5132
RH
3904number of low-order zero bits the location counter must have after
3905advancement. For example @samp{.align 3} advances the location
3906counter until it a multiple of 8. If the location counter is already a
3907multiple of 8, no change is needed.
3908
3909This inconsistency is due to the different behaviors of the various
3910native assemblers for these systems which GAS must emulate.
3911GAS also provides @code{.balign} and @code{.p2align} directives,
3912described later, which have a consistent behavior across all
3913architectures (but are specific to GAS).
3914
3915@node Ascii
3916@section @code{.ascii "@var{string}"}@dots{}
3917
3918@cindex @code{ascii} directive
3919@cindex string literals
3920@code{.ascii} expects zero or more string literals (@pxref{Strings})
3921separated by commas. It assembles each string (with no automatic
3922trailing zero byte) into consecutive addresses.
3923
3924@node Asciz
3925@section @code{.asciz "@var{string}"}@dots{}
3926
3927@cindex @code{asciz} directive
3928@cindex zero-terminated strings
3929@cindex null-terminated strings
3930@code{.asciz} is just like @code{.ascii}, but each string is followed by
3931a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
3932
3933@node Balign
3934@section @code{.balign[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3935
3936@cindex padding the location counter given number of bytes
3937@cindex @code{balign} directive
3938Pad the location counter (in the current subsection) to a particular
3939storage boundary. The first expression (which must be absolute) is the
3940alignment request in bytes. For example @samp{.balign 8} advances
3941the location counter until it is a multiple of 8. If the location counter
3942is already a multiple of 8, no change is needed.
3943
3944The second expression (also absolute) gives the fill value to be stored in the
3945padding bytes. It (and the comma) may be omitted. If it is omitted, the
3946padding bytes are normally zero. However, on some systems, if the section is
3947marked as containing code and the fill value is omitted, the space is filled
3948with no-op instructions.
3949
3950The third expression is also absolute, and is also optional. If it is present,
3951it is the maximum number of bytes that should be skipped by this alignment
3952directive. If doing the alignment would require skipping more bytes than the
3953specified maximum, then the alignment is not done at all. You can omit the
3954fill value (the second argument) entirely by simply using two commas after the
3955required alignment; this can be useful if you want the alignment to be filled
3956with no-op instructions when appropriate.
3957
3958@cindex @code{balignw} directive
3959@cindex @code{balignl} directive
3960The @code{.balignw} and @code{.balignl} directives are variants of the
3961@code{.balign} directive. The @code{.balignw} directive treats the fill
3962pattern as a two byte word value. The @code{.balignl} directives treats the
3963fill pattern as a four byte longword value. For example, @code{.balignw
39644,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
3965filled in with the value 0x368d (the exact placement of the bytes depends upon
3966the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
3967undefined.
3968
3969@node Byte
3970@section @code{.byte @var{expressions}}
3971
3972@cindex @code{byte} directive
3973@cindex integers, one byte
3974@code{.byte} expects zero or more expressions, separated by commas.
3975Each expression is assembled into the next byte.
3976
d88ef7a6
TT
3977@node Comm
3978@section @code{.comm @var{symbol} , @var{length} }
3979
3980@cindex @code{comm} directive
3981@cindex symbol, common
3982@code{.comm} declares a common symbol named @var{symbol}. When linking, a
3983common symbol in one object file may be merged with a defined or common symbol
3984of the same name in another object file. If @code{@value{LD}} does not see a
3985definition for the symbol--just one or more common symbols--then it will
3986allocate @var{length} bytes of uninitialized memory. @var{length} must be an
3987absolute expression. If @code{@value{LD}} sees multiple common symbols with
3988the same name, and they do not all have the same size, it will allocate space
3989using the largest size.
3990
3991@ifset ELF
3992When using ELF, the @code{.comm} directive takes an optional third argument.
3993This is the desired alignment of the symbol, specified as a byte boundary (for
3994example, an alignment of 16 means that the least significant 4 bits of the
3995address should be zero). The alignment must be an absolute expression, and it
3996must be a power of two. If @code{@value{LD}} allocates uninitialized memory
3997for the common symbol, it will use the alignment when placing the symbol. If
3998no alignment is specified, @command{@value{AS}} will set the alignment to the
3999largest power of two less than or equal to the size of the symbol, up to a
4000maximum of 16.
4001@end ifset
4002
4003@ifset HPPA
4004The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
4005@samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
4006@end ifset
4007
54cfded0
AM
4008@node CFI directives
4009@section @code{.cfi_startproc}
4010@cindex @code{cfi_startproc} directive
4011@code{.cfi_startproc} is used at the beginning of each function that
4012should have an entry in @code{.eh_frame}. It initializes some internal
4013data structures and emits architecture dependent initial CFI instructions.
4014Don't forget to close the function by
4015@code{.cfi_endproc}.
4016
4017@section @code{.cfi_endproc}
4018@cindex @code{cfi_endproc} directive
4019@code{.cfi_endproc} is used at the end of a function where it closes its
4020unwind entry previously opened by
4021@code{.cfi_startproc}. and emits it to @code{.eh_frame}.
4022
4023@section @code{.cfi_def_cfa @var{register}, @var{offset}}
4024@code{.cfi_def_cfa} defines a rule for computing CFA as: @i{take
4025address from @var{register} and add @var{offset} to it}.
4026
4027@section @code{.cfi_def_cfa_register @var{register}}
4028@code{.cfi_def_cfa_register} modifies a rule for computing CFA. From
4029now on @var{register} will be used instead of the old one. Offset
4030remains the same.
4031
4032@section @code{.cfi_def_cfa_offset @var{offset}}
4033@code{.cfi_def_cfa_offset} modifies a rule for computing CFA. Register
4034remains the same, but @var{offset} is new. Note that it is the
4035absolute offset that will be added to a defined register to compute
4036CFA address.
4037
4038@section @code{.cfi_adjust_cfa_offset @var{offset}}
4039Same as @code{.cfi_def_cfa_offset} but @var{offset} is a relative
4040value that is added/substracted from the previous offset.
4041
4042@section @code{.cfi_offset @var{register}, @var{offset}}
4043Previous value of @var{register} is saved at offset @var{offset} from
4044CFA.
4045
17076204
RH
4046@section @code{.cfi_rel_offset @var{register}, @var{offset}}
4047Previous value of @var{register} is saved at offset @var{offset} from
4048the current CFA register. This is transformed to @code{.cfi_offset}
4049using the known displacement of the CFA register from the CFA.
4050This is often easier to use, because the number will match the
4051code it's annotating.
54cfded0 4052
6749011b 4053@section @code{.cfi_window_save}
364b6d8b
JJ
4054SPARC register window has been saved.
4055
cdfbf930
RH
4056@section @code{.cfi_escape} @var{expression}[, @dots{}]
4057Allows the user to add arbitrary bytes to the unwind info. One
4058might use this to add OS-specific CFI opcodes, or generic CFI
4059opcodes that GAS does not yet support.
252b5132 4060
bd0eb99b
RH
4061@node LNS directives
4062@section @code{.file @var{fileno} @var{filename}}
4063@cindex @code{file} directive
4064When emitting dwarf2 line number information @code{.file} assigns filenames
4065to the @code{.debug_line} file name table. The @var{fileno} operand should
4066be a unique positive integer to use as the index of the entry in the table.
4067The @var{filename} operand is a C string literal.
4068
4069The detail of filename indicies is exposed to the user because the filename
4070table is shared with the @code{.debug_info} section of the dwarf2 debugging
4071information, and thus the user must know the exact indicies that table
4072entries will have.
4073
ecea7679 4074@section @code{.loc @var{fileno} @var{lineno} [@var{column}] [@var{options}]}
bd0eb99b
RH
4075@cindex @code{loc} directive
4076The @code{.loc} directive will add row to the @code{.debug_line} line
4077number matrix corresponding to the immediately following assembly
4078instruction. The @var{fileno}, @var{lineno}, and optional @var{column}
4079arguments will be applied to the @code{.debug_line} state machine before
4080the row is added.
4081
ecea7679
RH
4082The @var{options} are a sequence of the following tokens in any order:
4083
4084@table @code
4085@item basic_block
4086This option will set the @code{basic_block} register in the
bd0eb99b
RH
4087@code{.debug_line} state machine to @code{true}.
4088
ecea7679
RH
4089@item prologue_end
4090This option will set the @code{prologue_end} register in the
bd0eb99b
RH
4091@code{.debug_line} state machine to @code{true}.
4092
ecea7679
RH
4093@item epilogue_begin
4094This option will set the @code{epilogue_begin} register in the
bd0eb99b
RH
4095@code{.debug_line} state machine to @code{true}.
4096
ecea7679
RH
4097@item is_stmt @var{value}
4098This option will set the @code{is_stmt} register in the
bd0eb99b
RH
4099@code{.debug_line} state machine to @code{value}, which must be
4100either 0 or 1.
4101
ecea7679 4102@item isa @var{value}
bd0eb99b
RH
4103This directive will set the @code{isa} register in the @code{.debug_line}
4104state machine to @var{value}, which must be an unsigned integer.
07a53e5c
RH
4105
4106@section @code{.loc_mark_blocks @var{enable}}
4107@cindex @code{loc_mark_blocks} directive
4108The @code{.loc_mark_blocks} directive makes the assembler emit an entry
4109to the @code{.debug_line} line number matrix with the @code{basic_block}
4110register in the state machine set whenever a code label is seen.
4111The @var{enable} argument should be either 1 or 0, to enable or disable
4112this function respectively.
4113
ecea7679 4114@end table
bd0eb99b 4115
252b5132
RH
4116@node Data
4117@section @code{.data @var{subsection}}
4118
4119@cindex @code{data} directive
a4fb0134 4120@code{.data} tells @command{@value{AS}} to assemble the following statements onto the
252b5132
RH
4121end of the data subsection numbered @var{subsection} (which is an
4122absolute expression). If @var{subsection} is omitted, it defaults
4123to zero.
4124
4125@ifset COFF
4126@node Def
4127@section @code{.def @var{name}}
4128
4129@cindex @code{def} directive
4130@cindex COFF symbols, debugging
4131@cindex debugging COFF symbols
4132Begin defining debugging information for a symbol @var{name}; the
4133definition extends until the @code{.endef} directive is encountered.
4134@ifset BOUT
4135
a4fb0134 4136This directive is only observed when @command{@value{AS}} is configured for COFF
252b5132
RH
4137format output; when producing @code{b.out}, @samp{.def} is recognized,
4138but ignored.
4139@end ifset
4140@end ifset
4141
4142@ifset aout-bout
4143@node Desc
4144@section @code{.desc @var{symbol}, @var{abs-expression}}
4145
4146@cindex @code{desc} directive
4147@cindex COFF symbol descriptor
4148@cindex symbol descriptor, COFF
4149This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
4150to the low 16 bits of an absolute expression.
4151
4152@ifset COFF
a4fb0134 4153The @samp{.desc} directive is not available when @command{@value{AS}} is
252b5132 4154configured for COFF output; it is only for @code{a.out} or @code{b.out}
a4fb0134 4155object format. For the sake of compatibility, @command{@value{AS}} accepts
252b5132
RH
4156it, but produces no output, when configured for COFF.
4157@end ifset
4158@end ifset
4159
4160@ifset COFF
4161@node Dim
4162@section @code{.dim}
4163
4164@cindex @code{dim} directive
4165@cindex COFF auxiliary symbol information
4166@cindex auxiliary symbol information, COFF
4167This directive is generated by compilers to include auxiliary debugging
4168information in the symbol table. It is only permitted inside
4169@code{.def}/@code{.endef} pairs.
4170@ifset BOUT
4171
4172@samp{.dim} is only meaningful when generating COFF format output; when
a4fb0134 4173@command{@value{AS}} is generating @code{b.out}, it accepts this directive but
252b5132
RH
4174ignores it.
4175@end ifset
4176@end ifset
4177
4178@node Double
4179@section @code{.double @var{flonums}}
4180
4181@cindex @code{double} directive
4182@cindex floating point numbers (double)
4183@code{.double} expects zero or more flonums, separated by commas. It
4184assembles floating point numbers.
4185@ifset GENERIC
4186The exact kind of floating point numbers emitted depends on how
a4fb0134 4187@command{@value{AS}} is configured. @xref{Machine Dependencies}.
252b5132
RH
4188@end ifset
4189@ifclear GENERIC
4190@ifset IEEEFLOAT
4191On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers
4192in @sc{ieee} format.
4193@end ifset
4194@end ifclear
4195
4196@node Eject
4197@section @code{.eject}
4198
4199@cindex @code{eject} directive
4200@cindex new page, in listings
4201@cindex page, in listings
4202@cindex listing control: new page
4203Force a page break at this point, when generating assembly listings.
4204
4205@node Else
4206@section @code{.else}
4207
4208@cindex @code{else} directive
a4fb0134 4209@code{.else} is part of the @command{@value{AS}} support for conditional
252b5132
RH
4210assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section
4211of code to be assembled if the condition for the preceding @code{.if}
4212was false.
4213
3fd9f047
TW
4214@node Elseif
4215@section @code{.elseif}
4216
4217@cindex @code{elseif} directive
a4fb0134 4218@code{.elseif} is part of the @command{@value{AS}} support for conditional
3fd9f047
TW
4219assembly; @pxref{If,,@code{.if}}. It is shorthand for beginning a new
4220@code{.if} block that would otherwise fill the entire @code{.else} section.
4221
252b5132
RH
4222@node End
4223@section @code{.end}
4224
4225@cindex @code{end} directive
a4fb0134 4226@code{.end} marks the end of the assembly file. @command{@value{AS}} does not
252b5132
RH
4227process anything in the file past the @code{.end} directive.
4228
4229@ifset COFF
4230@node Endef
4231@section @code{.endef}
4232
4233@cindex @code{endef} directive
4234This directive flags the end of a symbol definition begun with
4235@code{.def}.
4236@ifset BOUT
4237
4238@samp{.endef} is only meaningful when generating COFF format output; if
a4fb0134 4239@command{@value{AS}} is configured to generate @code{b.out}, it accepts this
252b5132
RH
4240directive but ignores it.
4241@end ifset
4242@end ifset
4243
4244@node Endfunc
4245@section @code{.endfunc}
4246@cindex @code{endfunc} directive
4247@code{.endfunc} marks the end of a function specified with @code{.func}.
4248
4249@node Endif
4250@section @code{.endif}
4251
4252@cindex @code{endif} directive
a4fb0134 4253@code{.endif} is part of the @command{@value{AS}} support for conditional assembly;
252b5132
RH
4254it marks the end of a block of code that is only assembled
4255conditionally. @xref{If,,@code{.if}}.
4256
4257@node Equ
4258@section @code{.equ @var{symbol}, @var{expression}}
4259
4260@cindex @code{equ} directive
4261@cindex assigning values to symbols
4262@cindex symbols, assigning values to
4263This directive sets the value of @var{symbol} to @var{expression}.
4264It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
4265
4266@ifset HPPA
4267The syntax for @code{equ} on the HPPA is
4268@samp{@var{symbol} .equ @var{expression}}.
4269@end ifset
4270
4271@node Equiv
4272@section @code{.equiv @var{symbol}, @var{expression}}
4273@cindex @code{equiv} directive
4274The @code{.equiv} directive is like @code{.equ} and @code{.set}, except that
8dfa0188
NC
4275the assembler will signal an error if @var{symbol} is already defined. Note a
4276symbol which has been referenced but not actually defined is considered to be
4277undefined.
252b5132
RH
4278
4279Except for the contents of the error message, this is roughly equivalent to
4280@smallexample
4281.ifdef SYM
4282.err
4283.endif
4284.equ SYM,VAL
4285@end smallexample
4286
4287@node Err
4288@section @code{.err}
4289@cindex @code{err} directive
a4fb0134
SC
4290If @command{@value{AS}} assembles a @code{.err} directive, it will print an error
4291message and, unless the @option{-Z} option was used, it will not generate an
252b5132
RH
4292object file. This can be used to signal error an conditionally compiled code.
4293
d190d046
HPN
4294@node Error
4295@section @code{.error "@var{string}"}
4296@cindex error directive
4297
4298Similarly to @code{.err}, this directive emits an error, but you can specify a
4299string that will be emitted as the error message. If you don't specify the
4300message, it defaults to @code{".error directive invoked in source file"}.
4301@xref{Errors, ,Error and Warning Messages}.
4302
4303@smallexample
4304 .error "This code has not been assembled and tested."
4305@end smallexample
4306
252b5132
RH
4307@node Exitm
4308@section @code{.exitm}
4309Exit early from the current macro definition. @xref{Macro}.
4310
4311@node Extern
4312@section @code{.extern}
4313
4314@cindex @code{extern} directive
4315@code{.extern} is accepted in the source program---for compatibility
a4fb0134 4316with other assemblers---but it is ignored. @command{@value{AS}} treats
252b5132
RH
4317all undefined symbols as external.
4318
4319@node Fail
4320@section @code{.fail @var{expression}}
4321
4322@cindex @code{fail} directive
4323Generates an error or a warning. If the value of the @var{expression} is 500
a4fb0134
SC
4324or more, @command{@value{AS}} will print a warning message. If the value is less
4325than 500, @command{@value{AS}} will print an error message. The message will
252b5132
RH
4326include the value of @var{expression}. This can occasionally be useful inside
4327complex nested macros or conditional assembly.
4328
4329@ifclear no-file-dir
4330@node File
4331@section @code{.file @var{string}}
4332
4333@cindex @code{file} directive
4334@cindex logical file name
4335@cindex file name, logical
a4fb0134 4336@code{.file} tells @command{@value{AS}} that we are about to start a new logical
252b5132
RH
4337file. @var{string} is the new file name. In general, the filename is
4338recognized whether or not it is surrounded by quotes @samp{"}; but if you wish
4339to specify an empty file name, you must give the quotes--@code{""}. This
4340statement may go away in future: it is only recognized to be compatible with
a4fb0134 4341old @command{@value{AS}} programs.
252b5132
RH
4342@end ifclear
4343
4344@node Fill
4345@section @code{.fill @var{repeat} , @var{size} , @var{value}}
4346
4347@cindex @code{fill} directive
4348@cindex writing patterns in memory
4349@cindex patterns, writing in memory
bc64be0c 4350@var{repeat}, @var{size} and @var{value} are absolute expressions.
252b5132
RH
4351This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
4352may be zero or more. @var{Size} may be zero or more, but if it is
4353more than 8, then it is deemed to have the value 8, compatible with
4354other people's assemblers. The contents of each @var{repeat} bytes
4355is taken from an 8-byte number. The highest order 4 bytes are
4356zero. The lowest order 4 bytes are @var{value} rendered in the
a4fb0134 4357byte-order of an integer on the computer @command{@value{AS}} is assembling for.
252b5132
RH
4358Each @var{size} bytes in a repetition is taken from the lowest order
4359@var{size} bytes of this number. Again, this bizarre behavior is
4360compatible with other people's assemblers.
4361
4362@var{size} and @var{value} are optional.
4363If the second comma and @var{value} are absent, @var{value} is
4364assumed zero. If the first comma and following tokens are absent,
4365@var{size} is assumed to be 1.
4366
4367@node Float
4368@section @code{.float @var{flonums}}
4369
4370@cindex floating point numbers (single)
4371@cindex @code{float} directive
4372This directive assembles zero or more flonums, separated by commas. It
4373has the same effect as @code{.single}.
4374@ifset GENERIC
4375The exact kind of floating point numbers emitted depends on how
a4fb0134 4376@command{@value{AS}} is configured.
252b5132
RH
4377@xref{Machine Dependencies}.
4378@end ifset
4379@ifclear GENERIC
4380@ifset IEEEFLOAT
4381On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers
4382in @sc{ieee} format.
4383@end ifset
4384@end ifclear
4385
4386@node Func
4387@section @code{.func @var{name}[,@var{label}]}
4388@cindex @code{func} directive
4389@code{.func} emits debugging information to denote function @var{name}, and
4390is ignored unless the file is assembled with debugging enabled.
05da4302 4391Only @samp{--gstabs[+]} is currently supported.
252b5132
RH
4392@var{label} is the entry point of the function and if omitted @var{name}
4393prepended with the @samp{leading char} is used.
4394@samp{leading char} is usually @code{_} or nothing, depending on the target.
4395All functions are currently defined to have @code{void} return type.
4396The function must be terminated with @code{.endfunc}.
4397
4398@node Global
4399@section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
4400
4401@cindex @code{global} directive
4402@cindex symbol, making visible to linker
4403@code{.global} makes the symbol visible to @code{@value{LD}}. If you define
4404@var{symbol} in your partial program, its value is made available to
4405other partial programs that are linked with it. Otherwise,
4406@var{symbol} takes its attributes from a symbol of the same name
4407from another file linked into the same program.
4408
4409Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
4410compatibility with other assemblers.
4411
4412@ifset HPPA
4413On the HPPA, @code{.global} is not always enough to make it accessible to other
4414partial programs. You may need the HPPA-only @code{.EXPORT} directive as well.
4415@xref{HPPA Directives,, HPPA Assembler Directives}.
4416@end ifset
4417
c91d2e08
NC
4418@ifset ELF
4419@node Hidden
4420@section @code{.hidden @var{names}}
4421
c1253627
NC
4422@cindex @code{hidden} directive
4423@cindex visibility
ed9589d4 4424This is one of the ELF visibility directives. The other two are
a349d9dd
PB
4425@code{.internal} (@pxref{Internal,,@code{.internal}}) and
4426@code{.protected} (@pxref{Protected,,@code{.protected}}).
c91d2e08
NC
4427
4428This directive overrides the named symbols default visibility (which is set by
4429their binding: local, global or weak). The directive sets the visibility to
4430@code{hidden} which means that the symbols are not visible to other components.
4431Such symbols are always considered to be @code{protected} as well.
4432@end ifset
4433
252b5132
RH
4434@node hword
4435@section @code{.hword @var{expressions}}
4436
4437@cindex @code{hword} directive
4438@cindex integers, 16-bit
4439@cindex numbers, 16-bit
4440@cindex sixteen bit integers
4441This expects zero or more @var{expressions}, and emits
4442a 16 bit number for each.
4443
4444@ifset GENERIC
4445This directive is a synonym for @samp{.short}; depending on the target
4446architecture, it may also be a synonym for @samp{.word}.
4447@end ifset
4448@ifclear GENERIC
4449@ifset W32
4450This directive is a synonym for @samp{.short}.
4451@end ifset
4452@ifset W16
4453This directive is a synonym for both @samp{.short} and @samp{.word}.
4454@end ifset
4455@end ifclear
4456
4457@node Ident
4458@section @code{.ident}
4459
4460@cindex @code{ident} directive
4461This directive is used by some assemblers to place tags in object files.
a4fb0134 4462@command{@value{AS}} simply accepts the directive for source-file
252b5132
RH
4463compatibility with such assemblers, but does not actually emit anything
4464for it.
4465
4466@node If
4467@section @code{.if @var{absolute expression}}
4468
4469@cindex conditional assembly
4470@cindex @code{if} directive
4471@code{.if} marks the beginning of a section of code which is only
4472considered part of the source program being assembled if the argument
4473(which must be an @var{absolute expression}) is non-zero. The end of
4474the conditional section of code must be marked by @code{.endif}
4475(@pxref{Endif,,@code{.endif}}); optionally, you may include code for the
4476alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}).
3fd9f047
TW
4477If you have several conditions to check, @code{.elseif} may be used to avoid
4478nesting blocks if/else within each subsequent @code{.else} block.
252b5132
RH
4479
4480The following variants of @code{.if} are also supported:
4481@table @code
4482@cindex @code{ifdef} directive
4483@item .ifdef @var{symbol}
4484Assembles the following section of code if the specified @var{symbol}
8dfa0188
NC
4485has been defined. Note a symbol which has been referenced but not yet defined
4486is considered to be undefined.
252b5132 4487
26aca5f6
JB
4488@cindex @code{ifb} directive
4489@item .ifb @var{text}
4490Assembles the following section of code if the operand is blank (empty).
4491
252b5132
RH
4492@cindex @code{ifc} directive
4493@item .ifc @var{string1},@var{string2}
4494Assembles the following section of code if the two strings are the same. The
4495strings may be optionally quoted with single quotes. If they are not quoted,
4496the first string stops at the first comma, and the second string stops at the
4497end of the line. Strings which contain whitespace should be quoted. The
4498string comparison is case sensitive.
4499
4500@cindex @code{ifeq} directive
4501@item .ifeq @var{absolute expression}
4502Assembles the following section of code if the argument is zero.
4503
4504@cindex @code{ifeqs} directive
4505@item .ifeqs @var{string1},@var{string2}
4506Another form of @code{.ifc}. The strings must be quoted using double quotes.
4507
4508@cindex @code{ifge} directive
4509@item .ifge @var{absolute expression}
4510Assembles the following section of code if the argument is greater than or
4511equal to zero.
4512
4513@cindex @code{ifgt} directive
4514@item .ifgt @var{absolute expression}
4515Assembles the following section of code if the argument is greater than zero.
4516
4517@cindex @code{ifle} directive
4518@item .ifle @var{absolute expression}
4519Assembles the following section of code if the argument is less than or equal
4520to zero.
4521
4522@cindex @code{iflt} directive
4523@item .iflt @var{absolute expression}
4524Assembles the following section of code if the argument is less than zero.
4525
26aca5f6
JB
4526@cindex @code{ifnb} directive
4527@item .ifnb @var{text}
4528Like @code{.ifb}, but the sense of the test is reversed: this assembles the
4529following section of code if the operand is non-blank (non-empty).
4530
252b5132
RH
4531@cindex @code{ifnc} directive
4532@item .ifnc @var{string1},@var{string2}.
4533Like @code{.ifc}, but the sense of the test is reversed: this assembles the
4534following section of code if the two strings are not the same.
4535
4536@cindex @code{ifndef} directive
4537@cindex @code{ifnotdef} directive
4538@item .ifndef @var{symbol}
4539@itemx .ifnotdef @var{symbol}
4540Assembles the following section of code if the specified @var{symbol}
8dfa0188
NC
4541has not been defined. Both spelling variants are equivalent. Note a symbol
4542which has been referenced but not yet defined is considered to be undefined.
252b5132
RH
4543
4544@cindex @code{ifne} directive
4545@item .ifne @var{absolute expression}
4546Assembles the following section of code if the argument is not equal to zero
4547(in other words, this is equivalent to @code{.if}).
4548
4549@cindex @code{ifnes} directive
4550@item .ifnes @var{string1},@var{string2}
4551Like @code{.ifeqs}, but the sense of the test is reversed: this assembles the
4552following section of code if the two strings are not the same.
4553@end table
4554
7e005732
NC
4555@node Incbin
4556@section @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
4557
4558@cindex @code{incbin} directive
4559@cindex binary files, including
4560The @code{incbin} directive includes @var{file} verbatim at the current
4561location. You can control the search paths used with the @samp{-I} command-line
4562option (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4563around @var{file}.
4564
4565The @var{skip} argument skips a number of bytes from the start of the
4566@var{file}. The @var{count} argument indicates the maximum number of bytes to
15dcfbc3
NC
4567read. Note that the data is not aligned in any way, so it is the user's
4568responsibility to make sure that proper alignment is provided both before and
4569after the @code{incbin} directive.
7e005732 4570
252b5132
RH
4571@node Include
4572@section @code{.include "@var{file}"}
4573
4574@cindex @code{include} directive
4575@cindex supporting files, including
4576@cindex files, including
4577This directive provides a way to include supporting files at specified
4578points in your source program. The code from @var{file} is assembled as
4579if it followed the point of the @code{.include}; when the end of the
4580included file is reached, assembly of the original file continues. You
4581can control the search paths used with the @samp{-I} command-line option
4582(@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4583around @var{file}.
4584
4585@node Int
4586@section @code{.int @var{expressions}}
4587
4588@cindex @code{int} directive
4589@cindex integers, 32-bit
4590Expect zero or more @var{expressions}, of any section, separated by commas.
4591For each expression, emit a number that, at run time, is the value of that
4592expression. The byte order and bit size of the number depends on what kind
4593of target the assembly is for.
4594
4595@ifclear GENERIC
4596@ifset H8
7be1c489 4597On most forms of the H8/300, @code{.int} emits 16-bit
c2dcd04e 4598integers. On the H8/300H and the Renesas SH, however, @code{.int} emits
252b5132
RH
459932-bit integers.
4600@end ifset
4601@end ifclear
4602
c91d2e08
NC
4603@ifset ELF
4604@node Internal
4605@section @code{.internal @var{names}}
4606
c1253627
NC
4607@cindex @code{internal} directive
4608@cindex visibility
ed9589d4 4609This is one of the ELF visibility directives. The other two are
a349d9dd
PB
4610@code{.hidden} (@pxref{Hidden,,@code{.hidden}}) and
4611@code{.protected} (@pxref{Protected,,@code{.protected}}).
c91d2e08
NC
4612
4613This directive overrides the named symbols default visibility (which is set by
4614their binding: local, global or weak). The directive sets the visibility to
4615@code{internal} which means that the symbols are considered to be @code{hidden}
c1253627 4616(i.e., not visible to other components), and that some extra, processor specific
c91d2e08
NC
4617processing must also be performed upon the symbols as well.
4618@end ifset
4619
252b5132
RH
4620@node Irp
4621@section @code{.irp @var{symbol},@var{values}}@dots{}
4622
4623@cindex @code{irp} directive
4624Evaluate a sequence of statements assigning different values to @var{symbol}.
4625The sequence of statements starts at the @code{.irp} directive, and is
4626terminated by an @code{.endr} directive. For each @var{value}, @var{symbol} is
4627set to @var{value}, and the sequence of statements is assembled. If no
4628@var{value} is listed, the sequence of statements is assembled once, with
4629@var{symbol} set to the null string. To refer to @var{symbol} within the
4630sequence of statements, use @var{\symbol}.
4631
4632For example, assembling
4633
4634@example
4635 .irp param,1,2,3
4636 move d\param,sp@@-
4637 .endr
4638@end example
4639
4640is equivalent to assembling
4641
4642@example
4643 move d1,sp@@-
4644 move d2,sp@@-
4645 move d3,sp@@-
4646@end example
4647
5e75c3ab
JB
4648For some caveats with the spelling of @var{symbol}, see also the discussion
4649at @xref{Macro}.
4650
252b5132
RH
4651@node Irpc
4652@section @code{.irpc @var{symbol},@var{values}}@dots{}
4653
4654@cindex @code{irpc} directive
4655Evaluate a sequence of statements assigning different values to @var{symbol}.
4656The sequence of statements starts at the @code{.irpc} directive, and is
4657terminated by an @code{.endr} directive. For each character in @var{value},
4658@var{symbol} is set to the character, and the sequence of statements is
4659assembled. If no @var{value} is listed, the sequence of statements is
4660assembled once, with @var{symbol} set to the null string. To refer to
4661@var{symbol} within the sequence of statements, use @var{\symbol}.
4662
4663For example, assembling
4664
4665@example
4666 .irpc param,123
4667 move d\param,sp@@-
4668 .endr
4669@end example
4670
4671is equivalent to assembling
4672
4673@example
4674 move d1,sp@@-
4675 move d2,sp@@-
4676 move d3,sp@@-
4677@end example
4678
5e75c3ab
JB
4679For some caveats with the spelling of @var{symbol}, see also the discussion
4680at @xref{Macro}.
4681
252b5132
RH
4682@node Lcomm
4683@section @code{.lcomm @var{symbol} , @var{length}}
4684
4685@cindex @code{lcomm} directive
4686@cindex local common symbols
4687@cindex symbols, local common
4688Reserve @var{length} (an absolute expression) bytes for a local common
4689denoted by @var{symbol}. The section and value of @var{symbol} are
4690those of the new local common. The addresses are allocated in the bss
4691section, so that at run-time the bytes start off zeroed. @var{Symbol}
4692is not declared global (@pxref{Global,,@code{.global}}), so is normally
4693not visible to @code{@value{LD}}.
4694
4695@ifset GENERIC
4696Some targets permit a third argument to be used with @code{.lcomm}. This
4697argument specifies the desired alignment of the symbol in the bss section.
4698@end ifset
4699
4700@ifset HPPA
4701The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
4702@samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
4703@end ifset
4704
4705@node Lflags
4706@section @code{.lflags}
4707
4708@cindex @code{lflags} directive (ignored)
a4fb0134 4709@command{@value{AS}} accepts this directive, for compatibility with other
252b5132
RH
4710assemblers, but ignores it.
4711
4712@ifclear no-line-dir
4713@node Line
4714@section @code{.line @var{line-number}}
4715
4716@cindex @code{line} directive
4717@end ifclear
4718@ifset no-line-dir
4719@node Ln
4720@section @code{.ln @var{line-number}}
4721
4722@cindex @code{ln} directive
4723@end ifset
4724@cindex logical line number
4725@ifset aout-bout
4726Change the logical line number. @var{line-number} must be an absolute
4727expression. The next line has that logical line number. Therefore any other
4728statements on the current line (after a statement separator character) are
4729reported as on logical line number @var{line-number} @minus{} 1. One day
a4fb0134 4730@command{@value{AS}} will no longer support this directive: it is recognized only
252b5132
RH
4731for compatibility with existing assembler programs.
4732
252b5132
RH
4733@end ifset
4734
4735@ifclear no-line-dir
4736Even though this is a directive associated with the @code{a.out} or
a4fb0134 4737@code{b.out} object-code formats, @command{@value{AS}} still recognizes it
252b5132
RH
4738when producing COFF output, and treats @samp{.line} as though it
4739were the COFF @samp{.ln} @emph{if} it is found outside a
4740@code{.def}/@code{.endef} pair.
4741
4742Inside a @code{.def}, @samp{.line} is, instead, one of the directives
4743used by compilers to generate auxiliary symbol information for
4744debugging.
4745@end ifclear
4746
4747@node Linkonce
4748@section @code{.linkonce [@var{type}]}
4749@cindex COMDAT
4750@cindex @code{linkonce} directive
4751@cindex common sections
4752Mark the current section so that the linker only includes a single copy of it.
4753This may be used to include the same section in several different object files,
4754but ensure that the linker will only include it once in the final output file.
4755The @code{.linkonce} pseudo-op must be used for each instance of the section.
4756Duplicate sections are detected based on the section name, so it should be
4757unique.
4758
4759This directive is only supported by a few object file formats; as of this
4760writing, the only object file format which supports it is the Portable
4761Executable format used on Windows NT.
4762
4763The @var{type} argument is optional. If specified, it must be one of the
4764following strings. For example:
4765@smallexample
4766.linkonce same_size
4767@end smallexample
4768Not all types may be supported on all object file formats.
4769
4770@table @code
4771@item discard
4772Silently discard duplicate sections. This is the default.
4773
4774@item one_only
4775Warn if there are duplicate sections, but still keep only one copy.
4776
4777@item same_size
4778Warn if any of the duplicates have different sizes.
4779
4780@item same_contents
4781Warn if any of the duplicates do not have exactly the same contents.
4782@end table
4783
4784@node Ln
4785@section @code{.ln @var{line-number}}
4786
4787@cindex @code{ln} directive
4788@ifclear no-line-dir
4789@samp{.ln} is a synonym for @samp{.line}.
4790@end ifclear
4791@ifset no-line-dir
a4fb0134 4792Tell @command{@value{AS}} to change the logical line number. @var{line-number}
252b5132
RH
4793must be an absolute expression. The next line has that logical
4794line number, so any other statements on the current line (after a
4795statement separator character @code{;}) are reported as on logical
4796line number @var{line-number} @minus{} 1.
4797@ifset BOUT
4798
a4fb0134 4799This directive is accepted, but ignored, when @command{@value{AS}} is
252b5132
RH
4800configured for @code{b.out}; its effect is only associated with COFF
4801output format.
4802@end ifset
4803@end ifset
4804
4805@node MRI
4806@section @code{.mri @var{val}}
4807
4808@cindex @code{mri} directive
4809@cindex MRI mode, temporarily
a4fb0134
SC
4810If @var{val} is non-zero, this tells @command{@value{AS}} to enter MRI mode. If
4811@var{val} is zero, this tells @command{@value{AS}} to exit MRI mode. This change
252b5132
RH
4812affects code assembled until the next @code{.mri} directive, or until the end
4813of the file. @xref{M, MRI mode, MRI mode}.
4814
4815@node List
4816@section @code{.list}
4817
4818@cindex @code{list} directive
4819@cindex listing control, turning on
4820Control (in conjunction with the @code{.nolist} directive) whether or
4821not assembly listings are generated. These two directives maintain an
4822internal counter (which is zero initially). @code{.list} increments the
4823counter, and @code{.nolist} decrements it. Assembly listings are
4824generated whenever the counter is greater than zero.
4825
4826By default, listings are disabled. When you enable them (with the
4827@samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
4828the initial value of the listing counter is one.
4829
4830@node Long
4831@section @code{.long @var{expressions}}
4832
4833@cindex @code{long} directive
4834@code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}.
4835
4836@ignore
4837@c no one seems to know what this is for or whether this description is
4838@c what it really ought to do
4839@node Lsym
4840@section @code{.lsym @var{symbol}, @var{expression}}
4841
4842@cindex @code{lsym} directive
4843@cindex symbol, not referenced in assembly
4844@code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
4845the hash table, ensuring it cannot be referenced by name during the
4846rest of the assembly. This sets the attributes of the symbol to be
4847the same as the expression value:
4848@smallexample
4849@var{other} = @var{descriptor} = 0
4850@var{type} = @r{(section of @var{expression})}
4851@var{value} = @var{expression}
4852@end smallexample
4853@noindent
4854The new symbol is not flagged as external.
4855@end ignore
4856
4857@node Macro
4858@section @code{.macro}
4859
4860@cindex macros
4861The commands @code{.macro} and @code{.endm} allow you to define macros that
4862generate assembly output. For example, this definition specifies a macro
4863@code{sum} that puts a sequence of numbers into memory:
4864
4865@example
4866 .macro sum from=0, to=5
4867 .long \from
4868 .if \to-\from
4869 sum "(\from+1)",\to
4870 .endif
4871 .endm
4872@end example
4873
4874@noindent
4875With that definition, @samp{SUM 0,5} is equivalent to this assembly input:
4876
4877@example
4878 .long 0
4879 .long 1
4880 .long 2
4881 .long 3
4882 .long 4
4883 .long 5
4884@end example
4885
4886@ftable @code
4887@item .macro @var{macname}
4888@itemx .macro @var{macname} @var{macargs} @dots{}
4889@cindex @code{macro} directive
4890Begin the definition of a macro called @var{macname}. If your macro
4891definition requires arguments, specify their names after the macro name,
6eaeac8a
JB
4892separated by commas or spaces. You can qualify the macro argument to
4893indicate whether all invocations must specify a non-blank value (through
4894@samp{:@code{req}}), or whether it takes all of the remaining arguments
4895(through @samp{:@code{vararg}}). You can supply a default value for any
fffeaa5f
JB
4896macro argument by following the name with @samp{=@var{deflt}}. You
4897cannot define two macros with the same @var{macname} unless it has been
4898subject to the @code{.purgem} directive (@xref{Purgem}.) between the two
4899definitions. For example, these are all valid @code{.macro} statements:
252b5132
RH
4900
4901@table @code
4902@item .macro comm
4903Begin the definition of a macro called @code{comm}, which takes no
4904arguments.
4905
4906@item .macro plus1 p, p1
4907@itemx .macro plus1 p p1
4908Either statement begins the definition of a macro called @code{plus1},
4909which takes two arguments; within the macro definition, write
4910@samp{\p} or @samp{\p1} to evaluate the arguments.
4911
4912@item .macro reserve_str p1=0 p2
4913Begin the definition of a macro called @code{reserve_str}, with two
4914arguments. The first argument has a default value, but not the second.
4915After the definition is complete, you can call the macro either as
4916@samp{reserve_str @var{a},@var{b}} (with @samp{\p1} evaluating to
4917@var{a} and @samp{\p2} evaluating to @var{b}), or as @samp{reserve_str
4918,@var{b}} (with @samp{\p1} evaluating as the default, in this case
4919@samp{0}, and @samp{\p2} evaluating to @var{b}).
4920@end table
4921
6eaeac8a
JB
4922@item .macro m p1:req, p2=0, p3:vararg
4923Begin the definition of a macro called @code{m}, with at least three
4924arguments. The first argument must always have a value specified, but
4925not the second, which instead has a default value. The third formal
4926will get assigned all remaining arguments specified at invocation time.
4927
252b5132
RH
4928When you call a macro, you can specify the argument values either by
4929position, or by keyword. For example, @samp{sum 9,17} is equivalent to
4930@samp{sum to=17, from=9}.
4931
5e75c3ab
JB
4932Note that since each of the @var{macargs} can be an identifier exactly
4933as any other one permitted by the target architecture, there may be
4934occasional problems if the target hand-crafts special meanings to certain
4935characters when they occur in a special position. For example, if colon
4936(@code{:}) is generally permitted to be part of a symbol name, but the
4937architecture specific code special-cases it when occuring as the final
4938character of a symbol (to denote a label), then the macro parameter
4939replacement code will have no way of knowing that and consider the whole
4940construct (including the colon) an identifier, and check only this
4941identifier for being the subject to parameter substitution. In this
4942example, besides the potential of just separating identifier and colon
4943by white space, using alternate macro syntax (@xref{Altmacro}.) and
4944ampersand (@code{&}) as the character to separate literal text from macro
4945parameters (or macro parameters from one another) would provide a way to
4946achieve the same effect:
4947
4948@example
4949 .altmacro
4950 .macro label l
4951l&:
4952 .endm
4953@end example
4954
4955This applies identically to the identifiers used in @code{.irp} (@xref{Irp}.)
4956and @code{.irpc} (@xref{Irpc}.).
4957
252b5132
RH
4958@item .endm
4959@cindex @code{endm} directive
4960Mark the end of a macro definition.
4961
4962@item .exitm
4963@cindex @code{exitm} directive
4964Exit early from the current macro definition.
4965
4966@cindex number of macros executed
4967@cindex macros, count executed
4968@item \@@
a4fb0134 4969@command{@value{AS}} maintains a counter of how many macros it has
252b5132
RH
4970executed in this pseudo-variable; you can copy that number to your
4971output with @samp{\@@}, but @emph{only within a macro definition}.
4972
252b5132
RH
4973@item LOCAL @var{name} [ , @dots{} ]
4974@emph{Warning: @code{LOCAL} is only available if you select ``alternate
caa32fe5
NC
4975macro syntax'' with @samp{--alternate} or @code{.altmacro}.}
4976@xref{Altmacro,,@code{.altmacro}}.
4977@end ftable
252b5132 4978
caa32fe5
NC
4979@node Altmacro
4980@section @code{.altmacro}
4981Enable alternate macro mode, enabling:
4982
4983@ftable @code
4984@item LOCAL @var{name} [ , @dots{} ]
4985One additional directive, @code{LOCAL}, is available. It is used to
4986generate a string replacement for each of the @var{name} arguments, and
252b5132
RH
4987replace any instances of @var{name} in each macro expansion. The
4988replacement string is unique in the assembly, and different for each
4989separate macro expansion. @code{LOCAL} allows you to write macros that
4990define symbols, without fear of conflict between separate macro expansions.
caa32fe5
NC
4991
4992@item String delimiters
4993You can write strings delimited in these other ways besides
4994@code{"@var{string}"}:
4995
4996@table @code
4997@item '@var{string}'
4998You can delimit strings with single-quote charaters.
4999
5000@item <@var{string}>
5001You can delimit strings with matching angle brackets.
5002@end table
5003
5004@item single-character string escape
5005To include any single character literally in a string (even if the
5006character would otherwise have some special meaning), you can prefix the
5007character with @samp{!} (an exclamation mark). For example, you can
5008write @samp{<4.3 !> 5.4!!>} to get the literal text @samp{4.3 > 5.4!}.
5009
5010@item Expression results as strings
5011You can write @samp{%@var{expr}} to evaluate the expression @var{expr}
5012and use the result as a string.
252b5132
RH
5013@end ftable
5014
caa32fe5
NC
5015@node Noaltmacro
5016@section @code{.noaltmacro}
5017Disable alternate macro mode. @ref{Altmacro}
5018
252b5132
RH
5019@node Nolist
5020@section @code{.nolist}
5021
5022@cindex @code{nolist} directive
5023@cindex listing control, turning off
5024Control (in conjunction with the @code{.list} directive) whether or
5025not assembly listings are generated. These two directives maintain an
5026internal counter (which is zero initially). @code{.list} increments the
5027counter, and @code{.nolist} decrements it. Assembly listings are
5028generated whenever the counter is greater than zero.
5029
5030@node Octa
5031@section @code{.octa @var{bignums}}
5032
5033@c FIXME: double size emitted for "octa" on i960, others? Or warn?
5034@cindex @code{octa} directive
5035@cindex integer, 16-byte
5036@cindex sixteen byte integer
5037This directive expects zero or more bignums, separated by commas. For each
5038bignum, it emits a 16-byte integer.
5039
5040The term ``octa'' comes from contexts in which a ``word'' is two bytes;
5041hence @emph{octa}-word for 16 bytes.
5042
5043@node Org
5044@section @code{.org @var{new-lc} , @var{fill}}
5045
5046@cindex @code{org} directive
5047@cindex location counter, advancing
5048@cindex advancing location counter
5049@cindex current address, advancing
5050Advance the location counter of the current section to
5051@var{new-lc}. @var{new-lc} is either an absolute expression or an
5052expression with the same section as the current subsection. That is,
5053you can't use @code{.org} to cross sections: if @var{new-lc} has the
5054wrong section, the @code{.org} directive is ignored. To be compatible
5055with former assemblers, if the section of @var{new-lc} is absolute,
a4fb0134 5056@command{@value{AS}} issues a warning, then pretends the section of @var{new-lc}
252b5132
RH
5057is the same as the current subsection.
5058
5059@code{.org} may only increase the location counter, or leave it
5060unchanged; you cannot use @code{.org} to move the location counter
5061backwards.
5062
5063@c double negative used below "not undefined" because this is a specific
5064@c reference to "undefined" (as SEG_UNKNOWN is called in this manual)
5065@c section. doc@cygnus.com 18feb91
a4fb0134 5066Because @command{@value{AS}} tries to assemble programs in one pass, @var{new-lc}
252b5132
RH
5067may not be undefined. If you really detest this restriction we eagerly await
5068a chance to share your improved assembler.
5069
5070Beware that the origin is relative to the start of the section, not
5071to the start of the subsection. This is compatible with other
5072people's assemblers.
5073
5074When the location counter (of the current subsection) is advanced, the
5075intervening bytes are filled with @var{fill} which should be an
5076absolute expression. If the comma and @var{fill} are omitted,
5077@var{fill} defaults to zero.
5078
5079@node P2align
5080@section @code{.p2align[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
5081
5082@cindex padding the location counter given a power of two
5083@cindex @code{p2align} directive
5084Pad the location counter (in the current subsection) to a particular
5085storage boundary. The first expression (which must be absolute) is the
5086number of low-order zero bits the location counter must have after
5087advancement. For example @samp{.p2align 3} advances the location
5088counter until it a multiple of 8. If the location counter is already a
5089multiple of 8, no change is needed.
5090
5091The second expression (also absolute) gives the fill value to be stored in the
5092padding bytes. It (and the comma) may be omitted. If it is omitted, the
5093padding bytes are normally zero. However, on some systems, if the section is
5094marked as containing code and the fill value is omitted, the space is filled
5095with no-op instructions.
5096
5097The third expression is also absolute, and is also optional. If it is present,
5098it is the maximum number of bytes that should be skipped by this alignment
5099directive. If doing the alignment would require skipping more bytes than the
5100specified maximum, then the alignment is not done at all. You can omit the
5101fill value (the second argument) entirely by simply using two commas after the
5102required alignment; this can be useful if you want the alignment to be filled
5103with no-op instructions when appropriate.
5104
5105@cindex @code{p2alignw} directive
5106@cindex @code{p2alignl} directive
5107The @code{.p2alignw} and @code{.p2alignl} directives are variants of the
5108@code{.p2align} directive. The @code{.p2alignw} directive treats the fill
5109pattern as a two byte word value. The @code{.p2alignl} directives treats the
5110fill pattern as a four byte longword value. For example, @code{.p2alignw
51112,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
5112filled in with the value 0x368d (the exact placement of the bytes depends upon
5113the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
5114undefined.
5115
c91d2e08
NC
5116@ifset ELF
5117@node Previous
5118@section @code{.previous}
5119
c1253627 5120@cindex @code{previous} directive
c91d2e08
NC
5121@cindex Section Stack
5122This is one of the ELF section stack manipulation directives. The others are
a349d9dd
PB
5123@code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
5124@code{.pushsection} (@pxref{PushSection}), and @code{.popsection}
5125(@pxref{PopSection}).
c91d2e08
NC
5126
5127This directive swaps the current section (and subsection) with most recently
5128referenced section (and subsection) prior to this one. Multiple
5129@code{.previous} directives in a row will flip between two sections (and their
5130subsections).
5131
5132In terms of the section stack, this directive swaps the current section with
5133the top section on the section stack.
5134@end ifset
5135
5136@ifset ELF
5137@node PopSection
5138@section @code{.popsection}
5139
c1253627 5140@cindex @code{popsection} directive
c91d2e08
NC
5141@cindex Section Stack
5142This is one of the ELF section stack manipulation directives. The others are
a349d9dd
PB
5143@code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
5144@code{.pushsection} (@pxref{PushSection}), and @code{.previous}
5145(@pxref{Previous}).
c91d2e08
NC
5146
5147This directive replaces the current section (and subsection) with the top
5148section (and subsection) on the section stack. This section is popped off the
5149stack.
c91d2e08
NC
5150@end ifset
5151
252b5132
RH
5152@node Print
5153@section @code{.print @var{string}}
5154
5155@cindex @code{print} directive
a4fb0134 5156@command{@value{AS}} will print @var{string} on the standard output during
252b5132
RH
5157assembly. You must put @var{string} in double quotes.
5158
c91d2e08
NC
5159@ifset ELF
5160@node Protected
5161@section @code{.protected @var{names}}
5162
c1253627
NC
5163@cindex @code{protected} directive
5164@cindex visibility
ed9589d4 5165This is one of the ELF visibility directives. The other two are
a349d9dd 5166@code{.hidden} (@pxref{Hidden}) and @code{.internal} (@pxref{Internal}).
c91d2e08
NC
5167
5168This directive overrides the named symbols default visibility (which is set by
5169their binding: local, global or weak). The directive sets the visibility to
5170@code{protected} which means that any references to the symbols from within the
5171components that defines them must be resolved to the definition in that
5172component, even if a definition in another component would normally preempt
5173this.
5174@end ifset
5175
252b5132
RH
5176@node Psize
5177@section @code{.psize @var{lines} , @var{columns}}
5178
5179@cindex @code{psize} directive
5180@cindex listing control: paper size
5181@cindex paper size, for listings
5182Use this directive to declare the number of lines---and, optionally, the
5183number of columns---to use for each page, when generating listings.
5184
5185If you do not use @code{.psize}, listings use a default line-count
5186of 60. You may omit the comma and @var{columns} specification; the
5187default width is 200 columns.
5188
a4fb0134 5189@command{@value{AS}} generates formfeeds whenever the specified number of
252b5132
RH
5190lines is exceeded (or whenever you explicitly request one, using
5191@code{.eject}).
5192
5193If you specify @var{lines} as @code{0}, no formfeeds are generated save
5194those explicitly specified with @code{.eject}.
5195
5196@node Purgem
5197@section @code{.purgem @var{name}}
5198
5199@cindex @code{purgem} directive
5200Undefine the macro @var{name}, so that later uses of the string will not be
5201expanded. @xref{Macro}.
5202
c91d2e08
NC
5203@ifset ELF
5204@node PushSection
5205@section @code{.pushsection @var{name} , @var{subsection}}
5206
c1253627 5207@cindex @code{pushsection} directive
c91d2e08
NC
5208@cindex Section Stack
5209This is one of the ELF section stack manipulation directives. The others are
a349d9dd
PB
5210@code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
5211@code{.popsection} (@pxref{PopSection}), and @code{.previous}
5212(@pxref{Previous}).
c91d2e08 5213
e9863d7f
DJ
5214This directive pushes the current section (and subsection) onto the
5215top of the section stack, and then replaces the current section and
5216subsection with @code{name} and @code{subsection}.
c91d2e08
NC
5217@end ifset
5218
252b5132
RH
5219@node Quad
5220@section @code{.quad @var{bignums}}
5221
5222@cindex @code{quad} directive
5223@code{.quad} expects zero or more bignums, separated by commas. For
5224each bignum, it emits
5225@ifclear bignum-16
5226an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a
5227warning message; and just takes the lowest order 8 bytes of the bignum.
5228@cindex eight-byte integer
5229@cindex integer, 8-byte
5230
5231The term ``quad'' comes from contexts in which a ``word'' is two bytes;
5232hence @emph{quad}-word for 8 bytes.
5233@end ifclear
5234@ifset bignum-16
5235a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
5236warning message; and just takes the lowest order 16 bytes of the bignum.
5237@cindex sixteen-byte integer
5238@cindex integer, 16-byte
5239@end ifset
5240
5241@node Rept
5242@section @code{.rept @var{count}}
5243
5244@cindex @code{rept} directive
5245Repeat the sequence of lines between the @code{.rept} directive and the next
5246@code{.endr} directive @var{count} times.
5247
5248For example, assembling
5249
5250@example
5251 .rept 3
5252 .long 0
5253 .endr
5254@end example
5255
5256is equivalent to assembling
5257
5258@example
5259 .long 0
5260 .long 0
5261 .long 0
5262@end example
5263
5264@node Sbttl
5265@section @code{.sbttl "@var{subheading}"}
5266
5267@cindex @code{sbttl} directive
5268@cindex subtitles for listings
5269@cindex listing control: subtitle
5270Use @var{subheading} as the title (third line, immediately after the
5271title line) when generating assembly listings.
5272
5273This directive affects subsequent pages, as well as the current page if
5274it appears within ten lines of the top of a page.
5275
5276@ifset COFF
5277@node Scl
5278@section @code{.scl @var{class}}
5279
5280@cindex @code{scl} directive
5281@cindex symbol storage class (COFF)
5282@cindex COFF symbol storage class
5283Set the storage-class value for a symbol. This directive may only be
5284used inside a @code{.def}/@code{.endef} pair. Storage class may flag
5285whether a symbol is static or external, or it may record further
5286symbolic debugging information.
5287@ifset BOUT
5288
5289The @samp{.scl} directive is primarily associated with COFF output; when
a4fb0134 5290configured to generate @code{b.out} output format, @command{@value{AS}}
252b5132
RH
5291accepts this directive but ignores it.
5292@end ifset
5293@end ifset
5294
c1253627 5295@ifset COFF-ELF
252b5132 5296@node Section
c1253627 5297@section @code{.section @var{name}}
252b5132 5298
252b5132
RH
5299@cindex named section
5300Use the @code{.section} directive to assemble the following code into a section
5301named @var{name}.
5302
5303This directive is only supported for targets that actually support arbitrarily
5304named sections; on @code{a.out} targets, for example, it is not accepted, even
5305with a standard @code{a.out} section name.
5306
c1253627
NC
5307@ifset COFF
5308@ifset ELF
5309@c only print the extra heading if both COFF and ELF are set
5310@subheading COFF Version
5311@end ifset
5312
5313@cindex @code{section} directive (COFF version)
252b5132
RH
5314For COFF targets, the @code{.section} directive is used in one of the following
5315ways:
c91d2e08 5316
252b5132
RH
5317@smallexample
5318.section @var{name}[, "@var{flags}"]
5319.section @var{name}[, @var{subsegment}]
5320@end smallexample
5321
5322If the optional argument is quoted, it is taken as flags to use for the
5323section. Each flag is a single character. The following flags are recognized:
5324@table @code
5325@item b
5326bss section (uninitialized data)
5327@item n
5328section is not loaded
5329@item w
5330writable section
5331@item d
5332data section
5333@item r
5334read-only section
5335@item x
5336executable section
2dcc60be
ILT
5337@item s
5338shared section (meaningful for PE targets)
6ff96af6
NC
5339@item a
5340ignored. (For compatibility with the ELF version)
252b5132
RH
5341@end table
5342
5343If no flags are specified, the default flags depend upon the section name. If
5344the section name is not recognized, the default will be for the section to be
7e84d676
NC
5345loaded and writable. Note the @code{n} and @code{w} flags remove attributes
5346from the section, rather than adding them, so if they are used on their own it
5347will be as if no flags had been specified at all.
252b5132
RH
5348
5349If the optional argument to the @code{.section} directive is not quoted, it is
5350taken as a subsegment number (@pxref{Sub-Sections}).
c1253627 5351@end ifset
252b5132
RH
5352
5353@ifset ELF
c1253627
NC
5354@ifset COFF
5355@c only print the extra heading if both COFF and ELF are set
5356@subheading ELF Version
5357@end ifset
5358
c91d2e08
NC
5359@cindex Section Stack
5360This is one of the ELF section stack manipulation directives. The others are
a349d9dd
PB
5361@code{.subsection} (@pxref{SubSection}), @code{.pushsection}
5362(@pxref{PushSection}), @code{.popsection} (@pxref{PopSection}), and
5363@code{.previous} (@pxref{Previous}).
c91d2e08 5364
c1253627 5365@cindex @code{section} directive (ELF version)
252b5132 5366For ELF targets, the @code{.section} directive is used like this:
c91d2e08 5367
252b5132 5368@smallexample
22fe14ad 5369.section @var{name} [, "@var{flags}"[, @@@var{type}[,@var{flag_specific_arguments}]]
252b5132 5370@end smallexample
c91d2e08 5371
252b5132 5372The optional @var{flags} argument is a quoted string which may contain any
a349d9dd 5373combination of the following characters:
252b5132
RH
5374@table @code
5375@item a
5376section is allocatable
5377@item w
5378section is writable
5379@item x
5380section is executable
ec38dd05
JJ
5381@item M
5382section is mergeable
5383@item S
5384section contains zero terminated strings
22fe14ad
NC
5385@item G
5386section is a member of a section group
5387@item T
5388section is used for thread-local-storage
252b5132
RH
5389@end table
5390
5391The optional @var{type} argument may contain one of the following constants:
5392@table @code
5393@item @@progbits
5394section contains data
5395@item @@nobits
5396section does not contain data (i.e., section only occupies space)
22fe14ad
NC
5397@item @@note
5398section contains data which is used by things other than the program
10b016c2
PB
5399@item @@init_array
5400section contains an array of pointers to init functions
5401@item @@fini_array
5402section contains an array of pointers to finish functions
5403@item @@preinit_array
5404section contains an array of pointers to pre-init functions
252b5132
RH
5405@end table
5406
10b016c2
PB
5407Many targets only support the first three section types.
5408
ececec60
NC
5409Note on targets where the @code{@@} character is the start of a comment (eg
5410ARM) then another character is used instead. For example the ARM port uses the
5411@code{%} character.
5412
22fe14ad
NC
5413If @var{flags} contains the @code{M} symbol then the @var{type} argument must
5414be specified as well as an extra argument - @var{entsize} - like this:
5415
5416@smallexample
5417.section @var{name} , "@var{flags}"M, @@@var{type}, @var{entsize}
5418@end smallexample
5419
5420Sections with the @code{M} flag but not @code{S} flag must contain fixed size
5421constants, each @var{entsize} octets long. Sections with both @code{M} and
5422@code{S} must contain zero terminated strings where each character is
5423@var{entsize} bytes long. The linker may remove duplicates within sections with
5424the same name, same entity size and same flags. @var{entsize} must be an
5425absolute expression.
5426
5427If @var{flags} contains the @code{G} symbol then the @var{type} argument must
5428be present along with an additional field like this:
5429
5430@smallexample
5431.section @var{name} , "@var{flags}"G, @@@var{type}, @var{GroupName}[, @var{linkage}]
5432@end smallexample
5433
5434The @var{GroupName} field specifies the name of the section group to which this
5435particular section belongs. The optional linkage field can contain:
5436@table @code
5437@item comdat
5438indicates that only one copy of this section should be retained
5439@item .gnu.linkonce
5440an alias for comdat
5441@end table
5442
5443Note - if both the @var{M} and @var{G} flags are present then the fields for
5444the Merge flag should come first, like this:
5445
5446@smallexample
5447.section @var{name} , "@var{flags}"MG, @@@var{type}, @var{entsize}, @var{GroupName}[, @var{linkage}]
5448@end smallexample
ec38dd05 5449
252b5132
RH
5450If no flags are specified, the default flags depend upon the section name. If
5451the section name is not recognized, the default will be for the section to have
5452none of the above flags: it will not be allocated in memory, nor writable, nor
5453executable. The section will contain data.
5454
5455For ELF targets, the assembler supports another type of @code{.section}
5456directive for compatibility with the Solaris assembler:
c91d2e08 5457
252b5132
RH
5458@smallexample
5459.section "@var{name}"[, @var{flags}...]
5460@end smallexample
c91d2e08 5461
252b5132
RH
5462Note that the section name is quoted. There may be a sequence of comma
5463separated flags:
5464@table @code
5465@item #alloc
5466section is allocatable
5467@item #write
5468section is writable
5469@item #execinstr
5470section is executable
22fe14ad
NC
5471@item #tls
5472section is used for thread local storage
252b5132 5473@end table
c91d2e08 5474
e9863d7f
DJ
5475This directive replaces the current section and subsection. See the
5476contents of the gas testsuite directory @code{gas/testsuite/gas/elf} for
5477some examples of how this directive and the other section stack directives
5478work.
c1253627
NC
5479@end ifset
5480@end ifset
252b5132
RH
5481
5482@node Set
5483@section @code{.set @var{symbol}, @var{expression}}
5484
5485@cindex @code{set} directive
5486@cindex symbol value, setting
5487Set the value of @var{symbol} to @var{expression}. This
5488changes @var{symbol}'s value and type to conform to
5489@var{expression}. If @var{symbol} was flagged as external, it remains
5490flagged (@pxref{Symbol Attributes}).
5491
5492You may @code{.set} a symbol many times in the same assembly.
5493
5494If you @code{.set} a global symbol, the value stored in the object
5495file is the last value stored into it.
5496
5497@ifset HPPA
5498The syntax for @code{set} on the HPPA is
5499@samp{@var{symbol} .set @var{expression}}.
5500@end ifset
5501
5502@node Short
5503@section @code{.short @var{expressions}}
5504
5505@cindex @code{short} directive
5506@ifset GENERIC
5507@code{.short} is normally the same as @samp{.word}.
5508@xref{Word,,@code{.word}}.
5509
5510In some configurations, however, @code{.short} and @code{.word} generate
5511numbers of different lengths; @pxref{Machine Dependencies}.
5512@end ifset
5513@ifclear GENERIC
5514@ifset W16
5515@code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
5516@end ifset
5517@ifset W32
5518This expects zero or more @var{expressions}, and emits
5519a 16 bit number for each.
5520@end ifset
5521@end ifclear
5522
5523@node Single
5524@section @code{.single @var{flonums}}
5525
5526@cindex @code{single} directive
5527@cindex floating point numbers (single)
5528This directive assembles zero or more flonums, separated by commas. It
5529has the same effect as @code{.float}.
5530@ifset GENERIC
5531The exact kind of floating point numbers emitted depends on how
a4fb0134 5532@command{@value{AS}} is configured. @xref{Machine Dependencies}.
252b5132
RH
5533@end ifset
5534@ifclear GENERIC
5535@ifset IEEEFLOAT
5536On the @value{TARGET} family, @code{.single} emits 32-bit floating point
5537numbers in @sc{ieee} format.
5538@end ifset
5539@end ifclear
5540
c1253627 5541@ifset COFF-ELF
252b5132 5542@node Size
c1253627 5543@section @code{.size}
c91d2e08 5544
c1253627
NC
5545This directive is used to set the size associated with a symbol.
5546
5547@ifset COFF
5548@ifset ELF
5549@c only print the extra heading if both COFF and ELF are set
5550@subheading COFF Version
5551@end ifset
5552
5553@cindex @code{size} directive (COFF version)
5554For COFF targets, the @code{.size} directive is only permitted inside
5555@code{.def}/@code{.endef} pairs. It is used like this:
5556
5557@smallexample
5558.size @var{expression}
5559@end smallexample
252b5132 5560
c91d2e08 5561@ifset BOUT
252b5132 5562@samp{.size} is only meaningful when generating COFF format output; when
a4fb0134 5563@command{@value{AS}} is generating @code{b.out}, it accepts this directive but
252b5132
RH
5564ignores it.
5565@end ifset
c1253627 5566@end ifset
c91d2e08 5567
c1253627
NC
5568@ifset ELF
5569@ifset COFF
5570@c only print the extra heading if both COFF and ELF are set
5571@subheading ELF Version
5572@end ifset
5573
5574@cindex @code{size} directive (ELF version)
5575For ELF targets, the @code{.size} directive is used like this:
c91d2e08 5576
c1253627
NC
5577@smallexample
5578.size @var{name} , @var{expression}
5579@end smallexample
5580
5581This directive sets the size associated with a symbol @var{name}.
c91d2e08
NC
5582The size in bytes is computed from @var{expression} which can make use of label
5583arithmetic. This directive is typically used to set the size of function
5584symbols.
c1253627
NC
5585@end ifset
5586@end ifset
252b5132
RH
5587
5588@node Sleb128
5589@section @code{.sleb128 @var{expressions}}
5590
5591@cindex @code{sleb128} directive
5592@var{sleb128} stands for ``signed little endian base 128.'' This is a
5593compact, variable length representation of numbers used by the DWARF
5594symbolic debugging format. @xref{Uleb128,@code{.uleb128}}.
5595
5596@ifclear no-space-dir
5597@node Skip
5598@section @code{.skip @var{size} , @var{fill}}
5599
5600@cindex @code{skip} directive
5601@cindex filling memory
5602This directive emits @var{size} bytes, each of value @var{fill}. Both
5603@var{size} and @var{fill} are absolute expressions. If the comma and
5604@var{fill} are omitted, @var{fill} is assumed to be zero. This is the same as
5605@samp{.space}.
5606
5607@node Space
5608@section @code{.space @var{size} , @var{fill}}
5609
5610@cindex @code{space} directive
5611@cindex filling memory
5612This directive emits @var{size} bytes, each of value @var{fill}. Both
5613@var{size} and @var{fill} are absolute expressions. If the comma
5614and @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same
5615as @samp{.skip}.
5616
5617@ifset HPPA
5618@quotation
5619@emph{Warning:} @code{.space} has a completely different meaning for HPPA
5620targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
5621Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the
5622@code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives},
5623for a summary.
5624@end quotation
5625@end ifset
5626@end ifclear
5627
252b5132
RH
5628@ifset have-stabs
5629@node Stab
5630@section @code{.stabd, .stabn, .stabs}
5631
5632@cindex symbolic debuggers, information for
5633@cindex @code{stab@var{x}} directives
5634There are three directives that begin @samp{.stab}.
5635All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
a4fb0134 5636The symbols are not entered in the @command{@value{AS}} hash table: they
252b5132
RH
5637cannot be referenced elsewhere in the source file.
5638Up to five fields are required:
5639
5640@table @var
5641@item string
5642This is the symbol's name. It may contain any character except
5643@samp{\000}, so is more general than ordinary symbol names. Some
5644debuggers used to code arbitrarily complex structures into symbol names
5645using this field.
5646
5647@item type
5648An absolute expression. The symbol's type is set to the low 8 bits of
5649this expression. Any bit pattern is permitted, but @code{@value{LD}}
5650and debuggers choke on silly bit patterns.
5651
5652@item other
5653An absolute expression. The symbol's ``other'' attribute is set to the
5654low 8 bits of this expression.
5655
5656@item desc
5657An absolute expression. The symbol's descriptor is set to the low 16
5658bits of this expression.
5659
5660@item value
5661An absolute expression which becomes the symbol's value.
5662@end table
5663
5664If a warning is detected while reading a @code{.stabd}, @code{.stabn},
5665or @code{.stabs} statement, the symbol has probably already been created;
5666you get a half-formed symbol in your object file. This is
5667compatible with earlier assemblers!
5668
5669@table @code
5670@cindex @code{stabd} directive
5671@item .stabd @var{type} , @var{other} , @var{desc}
5672
5673The ``name'' of the symbol generated is not even an empty string.
5674It is a null pointer, for compatibility. Older assemblers used a
5675null pointer so they didn't waste space in object files with empty
5676strings.
5677
5678The symbol's value is set to the location counter,
5679relocatably. When your program is linked, the value of this symbol
5680is the address of the location counter when the @code{.stabd} was
5681assembled.
5682
5683@cindex @code{stabn} directive
5684@item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
5685The name of the symbol is set to the empty string @code{""}.
5686
5687@cindex @code{stabs} directive
5688@item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
5689All five fields are specified.
5690@end table
5691@end ifset
5692@c end have-stabs
5693
5694@node String
5695@section @code{.string} "@var{str}"
5696
5697@cindex string, copying to object file
5698@cindex @code{string} directive
5699
5700Copy the characters in @var{str} to the object file. You may specify more than
5701one string to copy, separated by commas. Unless otherwise specified for a
5702particular machine, the assembler marks the end of each string with a 0 byte.
5703You can use any of the escape sequences described in @ref{Strings,,Strings}.
5704
5705@node Struct
5706@section @code{.struct @var{expression}}
5707
5708@cindex @code{struct} directive
5709Switch to the absolute section, and set the section offset to @var{expression},
5710which must be an absolute expression. You might use this as follows:
5711@smallexample
5712 .struct 0
5713field1:
5714 .struct field1 + 4
5715field2:
5716 .struct field2 + 4
5717field3:
5718@end smallexample
5719This would define the symbol @code{field1} to have the value 0, the symbol
5720@code{field2} to have the value 4, and the symbol @code{field3} to have the
5721value 8. Assembly would be left in the absolute section, and you would need to
5722use a @code{.section} directive of some sort to change to some other section
5723before further assembly.
5724
c91d2e08
NC
5725@ifset ELF
5726@node SubSection
5727@section @code{.subsection @var{name}}
5728
c1253627 5729@cindex @code{subsection} directive
c91d2e08
NC
5730@cindex Section Stack
5731This is one of the ELF section stack manipulation directives. The others are
a349d9dd
PB
5732@code{.section} (@pxref{Section}), @code{.pushsection} (@pxref{PushSection}),
5733@code{.popsection} (@pxref{PopSection}), and @code{.previous}
5734(@pxref{Previous}).
c91d2e08
NC
5735
5736This directive replaces the current subsection with @code{name}. The current
5737section is not changed. The replaced subsection is put onto the section stack
5738in place of the then current top of stack subsection.
c91d2e08
NC
5739@end ifset
5740
252b5132
RH
5741@ifset ELF
5742@node Symver
5743@section @code{.symver}
5744@cindex @code{symver} directive
5745@cindex symbol versioning
5746@cindex versions of symbols
5747Use the @code{.symver} directive to bind symbols to specific version nodes
5748within a source file. This is only supported on ELF platforms, and is
5749typically used when assembling files to be linked into a shared library.
5750There are cases where it may make sense to use this in objects to be bound
5751into an application itself so as to override a versioned symbol from a
5752shared library.
5753
79082ff0 5754For ELF targets, the @code{.symver} directive can be used like this:
252b5132
RH
5755@smallexample
5756.symver @var{name}, @var{name2@@nodename}
5757@end smallexample
339681c0 5758If the symbol @var{name} is defined within the file
79082ff0 5759being assembled, the @code{.symver} directive effectively creates a symbol
252b5132
RH
5760alias with the name @var{name2@@nodename}, and in fact the main reason that we
5761just don't try and create a regular alias is that the @var{@@} character isn't
5762permitted in symbol names. The @var{name2} part of the name is the actual name
5763of the symbol by which it will be externally referenced. The name @var{name}
5764itself is merely a name of convenience that is used so that it is possible to
5765have definitions for multiple versions of a function within a single source
5766file, and so that the compiler can unambiguously know which version of a
5767function is being mentioned. The @var{nodename} portion of the alias should be
5768the name of a node specified in the version script supplied to the linker when
5769building a shared library. If you are attempting to override a versioned
5770symbol from a shared library, then @var{nodename} should correspond to the
5771nodename of the symbol you are trying to override.
339681c0
L
5772
5773If the symbol @var{name} is not defined within the file being assembled, all
5774references to @var{name} will be changed to @var{name2@@nodename}. If no
5775reference to @var{name} is made, @var{name2@@nodename} will be removed from the
5776symbol table.
79082ff0
L
5777
5778Another usage of the @code{.symver} directive is:
5779@smallexample
5780.symver @var{name}, @var{name2@@@@nodename}
5781@end smallexample
5782In this case, the symbol @var{name} must exist and be defined within
a349d9dd 5783the file being assembled. It is similar to @var{name2@@nodename}. The
79082ff0
L
5784difference is @var{name2@@@@nodename} will also be used to resolve
5785references to @var{name2} by the linker.
5786
5787The third usage of the @code{.symver} directive is:
5788@smallexample
5789.symver @var{name}, @var{name2@@@@@@nodename}
5790@end smallexample
5791When @var{name} is not defined within the
5792file being assembled, it is treated as @var{name2@@nodename}. When
5793@var{name} is defined within the file being assembled, the symbol
5794name, @var{name}, will be changed to @var{name2@@@@nodename}.
252b5132
RH
5795@end ifset
5796
5797@ifset COFF
5798@node Tag
5799@section @code{.tag @var{structname}}
5800
5801@cindex COFF structure debugging
5802@cindex structure debugging, COFF
5803@cindex @code{tag} directive
5804This directive is generated by compilers to include auxiliary debugging
5805information in the symbol table. It is only permitted inside
5806@code{.def}/@code{.endef} pairs. Tags are used to link structure
5807definitions in the symbol table with instances of those structures.
5808@ifset BOUT
5809
5810@samp{.tag} is only used when generating COFF format output; when
a4fb0134 5811@command{@value{AS}} is generating @code{b.out}, it accepts this directive but
252b5132
RH
5812ignores it.
5813@end ifset
5814@end ifset
5815
5816@node Text
5817@section @code{.text @var{subsection}}
5818
5819@cindex @code{text} directive
a4fb0134 5820Tells @command{@value{AS}} to assemble the following statements onto the end of
252b5132
RH
5821the text subsection numbered @var{subsection}, which is an absolute
5822expression. If @var{subsection} is omitted, subsection number zero
5823is used.
5824
5825@node Title
5826@section @code{.title "@var{heading}"}
5827
5828@cindex @code{title} directive
5829@cindex listing control: title line
5830Use @var{heading} as the title (second line, immediately after the
5831source file name and pagenumber) when generating assembly listings.
5832
5833This directive affects subsequent pages, as well as the current page if
5834it appears within ten lines of the top of a page.
5835
c1253627 5836@ifset COFF-ELF
252b5132 5837@node Type
c1253627
NC
5838@section @code{.type}
5839
5840This directive is used to set the type of a symbol.
5841
5842@ifset COFF
5843@ifset ELF
5844@c only print the extra heading if both COFF and ELF are set
5845@subheading COFF Version
5846@end ifset
252b5132
RH
5847
5848@cindex COFF symbol type
5849@cindex symbol type, COFF
c1253627
NC
5850@cindex @code{type} directive (COFF version)
5851For COFF targets, this directive is permitted only within
5852@code{.def}/@code{.endef} pairs. It is used like this:
5853
5854@smallexample
5855.type @var{int}
5856@end smallexample
5857
5858This records the integer @var{int} as the type attribute of a symbol table
5859entry.
252b5132 5860
c91d2e08 5861@ifset BOUT
252b5132 5862@samp{.type} is associated only with COFF format output; when
a4fb0134 5863@command{@value{AS}} is configured for @code{b.out} output, it accepts this
252b5132
RH
5864directive but ignores it.
5865@end ifset
c1253627 5866@end ifset
c91d2e08 5867
c1253627
NC
5868@ifset ELF
5869@ifset COFF
5870@c only print the extra heading if both COFF and ELF are set
5871@subheading ELF Version
5872@end ifset
c91d2e08
NC
5873
5874@cindex ELF symbol type
5875@cindex symbol type, ELF
c1253627
NC
5876@cindex @code{type} directive (ELF version)
5877For ELF targets, the @code{.type} directive is used like this:
5878
5879@smallexample
5880.type @var{name} , @var{type description}
5881@end smallexample
5882
5883This sets the type of symbol @var{name} to be either a
a349d9dd 5884function symbol or an object symbol. There are five different syntaxes
c91d2e08 5885supported for the @var{type description} field, in order to provide
a349d9dd 5886compatibility with various other assemblers. The syntaxes supported are:
c91d2e08
NC
5887
5888@smallexample
5889 .type <name>,#function
5890 .type <name>,#object
5891
5892 .type <name>,@@function
5893 .type <name>,@@object
5894
5895 .type <name>,%function
5896 .type <name>,%object
5897
5898 .type <name>,"function"
5899 .type <name>,"object"
5900
5901 .type <name> STT_FUNCTION
5902 .type <name> STT_OBJECT
5903@end smallexample
c1253627
NC
5904@end ifset
5905@end ifset
c91d2e08
NC
5906
5907@node Uleb128
5908@section @code{.uleb128 @var{expressions}}
5909
5910@cindex @code{uleb128} directive
5911@var{uleb128} stands for ``unsigned little endian base 128.'' This is a
5912compact, variable length representation of numbers used by the DWARF
5913symbolic debugging format. @xref{Sleb128,@code{.sleb128}}.
252b5132
RH
5914
5915@ifset COFF
5916@node Val
5917@section @code{.val @var{addr}}
5918
5919@cindex @code{val} directive
5920@cindex COFF value attribute
5921@cindex value attribute, COFF
5922This directive, permitted only within @code{.def}/@code{.endef} pairs,
5923records the address @var{addr} as the value attribute of a symbol table
5924entry.
5925@ifset BOUT
5926
a4fb0134 5927@samp{.val} is used only for COFF output; when @command{@value{AS}} is
252b5132
RH
5928configured for @code{b.out}, it accepts this directive but ignores it.
5929@end ifset
5930@end ifset
5931
2e13b764 5932@ifset ELF
c91d2e08
NC
5933@node Version
5934@section @code{.version "@var{string}"}
2e13b764 5935
c1253627 5936@cindex @code{version} directive
c91d2e08
NC
5937This directive creates a @code{.note} section and places into it an ELF
5938formatted note of type NT_VERSION. The note's name is set to @code{string}.
9a297610 5939@end ifset
2e13b764 5940
c91d2e08
NC
5941@ifset ELF
5942@node VTableEntry
5943@section @code{.vtable_entry @var{table}, @var{offset}}
2e13b764 5944
653cfe85 5945@cindex @code{vtable_entry} directive
c91d2e08
NC
5946This directive finds or creates a symbol @code{table} and creates a
5947@code{VTABLE_ENTRY} relocation for it with an addend of @code{offset}.
2e13b764 5948
c91d2e08
NC
5949@node VTableInherit
5950@section @code{.vtable_inherit @var{child}, @var{parent}}
2e13b764 5951
653cfe85 5952@cindex @code{vtable_inherit} directive
c91d2e08
NC
5953This directive finds the symbol @code{child} and finds or creates the symbol
5954@code{parent} and then creates a @code{VTABLE_INHERIT} relocation for the
a349d9dd 5955parent whose addend is the value of the child symbol. As a special case the
c91d2e08
NC
5956parent name of @code{0} is treated as refering the @code{*ABS*} section.
5957@end ifset
2e13b764 5958
d190d046
HPN
5959@node Warning
5960@section @code{.warning "@var{string}"}
5961@cindex warning directive
5962Similar to the directive @code{.error}
5963(@pxref{Error,,@code{.error "@var{string}"}}), but just emits a warning.
5964
c91d2e08
NC
5965@node Weak
5966@section @code{.weak @var{names}}
2e13b764 5967
c1253627 5968@cindex @code{weak} directive
a349d9dd 5969This directive sets the weak attribute on the comma separated list of symbol
c91d2e08 5970@code{names}. If the symbols do not already exist, they will be created.
c87db184 5971
977cdf5a
NC
5972On COFF targets other than PE, weak symbols are a GNU extension. This
5973directive sets the weak attribute on the comma separated list of symbol
c87db184
CF
5974@code{names}. If the symbols do not already exist, they will be created.
5975
977cdf5a
NC
5976On the PE target, weak symbols are supported natively as weak aliases.
5977When a weak symbol is created that is not an alias, GAS creates an
5978alternate symbol to hold the default value.
2e13b764 5979
252b5132
RH
5980@node Word
5981@section @code{.word @var{expressions}}
5982
5983@cindex @code{word} directive
5984This directive expects zero or more @var{expressions}, of any section,
5985separated by commas.
5986@ifclear GENERIC
5987@ifset W32
a4fb0134 5988For each expression, @command{@value{AS}} emits a 32-bit number.
252b5132
RH
5989@end ifset
5990@ifset W16
a4fb0134 5991For each expression, @command{@value{AS}} emits a 16-bit number.
252b5132
RH
5992@end ifset
5993@end ifclear
5994@ifset GENERIC
5995
5996The size of the number emitted, and its byte order,
5997depend on what target computer the assembly is for.
5998@end ifset
5999
6000@c on amd29k, i960, sparc the "special treatment to support compilers" doesn't
6001@c happen---32-bit addressability, period; no long/short jumps.
6002@ifset DIFF-TBL-KLUGE
6003@cindex difference tables altered
6004@cindex altered difference tables
6005@quotation
6006@emph{Warning: Special Treatment to support Compilers}
6007@end quotation
6008
6009@ifset GENERIC
6010Machines with a 32-bit address space, but that do less than 32-bit
6011addressing, require the following special treatment. If the machine of
6012interest to you does 32-bit addressing (or doesn't require it;
6013@pxref{Machine Dependencies}), you can ignore this issue.
6014
6015@end ifset
6016In order to assemble compiler output into something that works,
a4fb0134 6017@command{@value{AS}} occasionally does strange things to @samp{.word} directives.
252b5132 6018Directives of the form @samp{.word sym1-sym2} are often emitted by
a4fb0134 6019compilers as part of jump tables. Therefore, when @command{@value{AS}} assembles a
252b5132 6020directive of the form @samp{.word sym1-sym2}, and the difference between
a4fb0134 6021@code{sym1} and @code{sym2} does not fit in 16 bits, @command{@value{AS}}
252b5132
RH
6022creates a @dfn{secondary jump table}, immediately before the next label.
6023This secondary jump table is preceded by a short-jump to the
6024first byte after the secondary table. This short-jump prevents the flow
6025of control from accidentally falling into the new table. Inside the
6026table is a long-jump to @code{sym2}. The original @samp{.word}
6027contains @code{sym1} minus the address of the long-jump to
6028@code{sym2}.
6029
6030If there were several occurrences of @samp{.word sym1-sym2} before the
6031secondary jump table, all of them are adjusted. If there was a
6032@samp{.word sym3-sym4}, that also did not fit in sixteen bits, a
6033long-jump to @code{sym4} is included in the secondary jump table,
6034and the @code{.word} directives are adjusted to contain @code{sym3}
6035minus the address of the long-jump to @code{sym4}; and so on, for as many
6036entries in the original jump table as necessary.
6037
6038@ifset INTERNALS
a4fb0134 6039@emph{This feature may be disabled by compiling @command{@value{AS}} with the
252b5132
RH
6040@samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse
6041assembly language programmers.
6042@end ifset
6043@end ifset
6044@c end DIFF-TBL-KLUGE
6045
6046@node Deprecated
6047@section Deprecated Directives
6048
6049@cindex deprecated directives
6050@cindex obsolescent directives
6051One day these directives won't work.
6052They are included for compatibility with older assemblers.
6053@table @t
6054@item .abort
6055@item .line
6056@end table
6057
6058@ifset GENERIC
6059@node Machine Dependencies
6060@chapter Machine Dependent Features
6061
6062@cindex machine dependencies
6063The machine instruction sets are (almost by definition) different on
a4fb0134
SC
6064each machine where @command{@value{AS}} runs. Floating point representations
6065vary as well, and @command{@value{AS}} often supports a few additional
252b5132
RH
6066directives or command-line options for compatibility with other
6067assemblers on a particular platform. Finally, some versions of
a4fb0134 6068@command{@value{AS}} support special pseudo-instructions for branch
252b5132
RH
6069optimization.
6070
6071This chapter discusses most of these differences, though it does not
6072include details on any machine's instruction set. For details on that
6073subject, see the hardware manufacturer's manual.
6074
6075@menu
625e1353
RH
6076@ifset ALPHA
6077* Alpha-Dependent:: Alpha Dependent Features
6078@end ifset
252b5132
RH
6079@ifset ARC
6080* ARC-Dependent:: ARC Dependent Features
6081@end ifset
6082@ifset ARM
6083* ARM-Dependent:: ARM Dependent Features
6084@end ifset
07c1b327
CM
6085@ifset BFIN
6086* BFIN-Dependent:: BFIN Dependent Features
6087@end ifset
8bf549a8 6088@ifset CRIS
328eb32e
HPN
6089* CRIS-Dependent:: CRIS Dependent Features
6090@end ifset
252b5132
RH
6091@ifset D10V
6092* D10V-Dependent:: D10V Dependent Features
6093@end ifset
6094@ifset D30V
6095* D30V-Dependent:: D30V Dependent Features
6096@end ifset
6097@ifset H8/300
c2dcd04e 6098* H8/300-Dependent:: Renesas H8/300 Dependent Features
252b5132 6099@end ifset
252b5132
RH
6100@ifset HPPA
6101* HPPA-Dependent:: HPPA Dependent Features
6102@end ifset
5b93d8bb
AM
6103@ifset I370
6104* ESA/390-Dependent:: IBM ESA/390 Dependent Features
6105@end ifset
252b5132 6106@ifset I80386
55b62671 6107* i386-Dependent:: Intel 80386 and AMD x86-64 Dependent Features
252b5132 6108@end ifset
e3308d0d
JE
6109@ifset I860
6110* i860-Dependent:: Intel 80860 Dependent Features
6111@end ifset
252b5132
RH
6112@ifset I960
6113* i960-Dependent:: Intel 80960 Dependent Features
6114@end ifset
5cb53c21
L
6115@ifset IA64
6116* IA-64-Dependent:: Intel IA-64 Dependent Features
6117@end ifset
a40cbfa3
NC
6118@ifset IP2K
6119* IP2K-Dependent:: IP2K Dependent Features
6120@end ifset
49f58d10
JB
6121@ifset M32C
6122* M32C-Dependent:: M32C Dependent Features
6123@end ifset
ec694b89
NC
6124@ifset M32R
6125* M32R-Dependent:: M32R Dependent Features
6126@end ifset
252b5132
RH
6127@ifset M680X0
6128* M68K-Dependent:: M680x0 Dependent Features
6129@end ifset
60bcf0fa
NC
6130@ifset M68HC11
6131* M68HC11-Dependent:: M68HC11 and 68HC12 Dependent Features
6132@end ifset
252b5132
RH
6133@ifset MIPS
6134* MIPS-Dependent:: MIPS Dependent Features
6135@end ifset
3c3bdf30
NC
6136@ifset MMIX
6137* MMIX-Dependent:: MMIX Dependent Features
6138@end ifset
2469cfa2
NC
6139@ifset MSP430
6140* MSP430-Dependent:: MSP430 Dependent Features
6141@end ifset
252b5132 6142@ifset SH
ef230218
JR
6143* SH-Dependent:: Renesas / SuperH SH Dependent Features
6144* SH64-Dependent:: SuperH SH64 Dependent Features
252b5132 6145@end ifset
e135f41b
NC
6146@ifset PDP11
6147* PDP-11-Dependent:: PDP-11 Dependent Features
6148@end ifset
041dd5a9
ILT
6149@ifset PJ
6150* PJ-Dependent:: picoJava Dependent Features
6151@end ifset
418c1742
MG
6152@ifset PPC
6153* PPC-Dependent:: PowerPC Dependent Features
6154@end ifset
252b5132
RH
6155@ifset SPARC
6156* Sparc-Dependent:: SPARC Dependent Features
6157@end ifset
39bec121
TW
6158@ifset TIC54X
6159* TIC54X-Dependent:: TI TMS320C54x Dependent Features
6160@end ifset
252b5132
RH
6161@ifset V850
6162* V850-Dependent:: V850 Dependent Features
6163@end ifset
e0001a05
NC
6164@ifset XTENSA
6165* Xtensa-Dependent:: Xtensa Dependent Features
6166@end ifset
252b5132
RH
6167@ifset Z8000
6168* Z8000-Dependent:: Z8000 Dependent Features
6169@end ifset
6170@ifset VAX
6171* Vax-Dependent:: VAX Dependent Features
6172@end ifset
6173@end menu
6174
6175@lowersections
6176@end ifset
6177
6178@c The following major nodes are *sections* in the GENERIC version, *chapters*
6179@c in single-cpu versions. This is mainly achieved by @lowersections. There is a
6180@c peculiarity: to preserve cross-references, there must be a node called
6181@c "Machine Dependencies". Hence the conditional nodenames in each
6182@c major node below. Node defaulting in makeinfo requires adjacency of
6183@c node and sectioning commands; hence the repetition of @chapter BLAH
6184@c in both conditional blocks.
6185
625e1353
RH
6186@ifset ALPHA
6187@include c-alpha.texi
6188@end ifset
6189
6190@ifset ARC
6191@include c-arc.texi
6192@end ifset
6193
252b5132
RH
6194@ifset ARM
6195@include c-arm.texi
6196@end ifset
6197
07c1b327
CM
6198@ifset BFIN
6199@include c-bfin.texi
6200@end ifset
6201
328eb32e
HPN
6202@ifset CRIS
6203@include c-cris.texi
6204@end ifset
6205
c2dcd04e 6206@ifset Renesas-all
252b5132
RH
6207@ifclear GENERIC
6208@node Machine Dependencies
6209@chapter Machine Dependent Features
6210
c2dcd04e 6211The machine instruction sets are different on each Renesas chip family,
252b5132 6212and there are also some syntax differences among the families. This
a4fb0134 6213chapter describes the specific @command{@value{AS}} features for each
252b5132
RH
6214family.
6215
6216@menu
c2dcd04e 6217* H8/300-Dependent:: Renesas H8/300 Dependent Features
c2dcd04e 6218* SH-Dependent:: Renesas SH Dependent Features
252b5132
RH
6219@end menu
6220@lowersections
6221@end ifclear
6222@end ifset
6223
6224@ifset D10V
6225@include c-d10v.texi
6226@end ifset
6227
6228@ifset D30V
6229@include c-d30v.texi
6230@end ifset
6231
6232@ifset H8/300
6233@include c-h8300.texi
6234@end ifset
6235
252b5132
RH
6236@ifset HPPA
6237@include c-hppa.texi
6238@end ifset
6239
5b93d8bb
AM
6240@ifset I370
6241@include c-i370.texi
6242@end ifset
6243
252b5132
RH
6244@ifset I80386
6245@include c-i386.texi
6246@end ifset
6247
e3308d0d
JE
6248@ifset I860
6249@include c-i860.texi
6250@end ifset
6251
252b5132
RH
6252@ifset I960
6253@include c-i960.texi
6254@end ifset
6255
9e32ca89
NC
6256@ifset IA64
6257@include c-ia64.texi
6258@end ifset
6259
a40cbfa3
NC
6260@ifset IP2K
6261@include c-ip2k.texi
6262@end ifset
6263
49f58d10
JB
6264@ifset M32C
6265@include c-m32c.texi
6266@end ifset
6267
ec694b89
NC
6268@ifset M32R
6269@include c-m32r.texi
6270@end ifset
252b5132
RH
6271
6272@ifset M680X0
6273@include c-m68k.texi
6274@end ifset
6275
60bcf0fa
NC
6276@ifset M68HC11
6277@include c-m68hc11.texi
6278@end ifset
6279
252b5132
RH
6280@ifset MIPS
6281@include c-mips.texi
6282@end ifset
6283
3c3bdf30
NC
6284@ifset MMIX
6285@include c-mmix.texi
6286@end ifset
6287
2469cfa2
NC
6288@ifset MSP430
6289@include c-msp430.texi
6290@end ifset
6291
252b5132
RH
6292@ifset NS32K
6293@include c-ns32k.texi
6294@end ifset
6295
e135f41b
NC
6296@ifset PDP11
6297@include c-pdp11.texi
6298@end ifset
6299
041dd5a9
ILT
6300@ifset PJ
6301@include c-pj.texi
6302@end ifset
6303
418c1742
MG
6304@ifset PPC
6305@include c-ppc.texi
6306@end ifset
6307
252b5132
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6308@ifset SH
6309@include c-sh.texi
324bfcf3 6310@include c-sh64.texi
252b5132
RH
6311@end ifset
6312
6313@ifset SPARC
6314@include c-sparc.texi
6315@end ifset
6316
39bec121
TW
6317@ifset TIC54X
6318@include c-tic54x.texi
6319@end ifset
6320
252b5132
RH
6321@ifset Z8000
6322@include c-z8k.texi
6323@end ifset
6324
6325@ifset VAX
6326@include c-vax.texi
6327@end ifset
6328
6329@ifset V850
6330@include c-v850.texi
6331@end ifset
6332
e0001a05
NC
6333@ifset XTENSA
6334@include c-xtensa.texi
6335@end ifset
6336
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6337@ifset GENERIC
6338@c reverse effect of @down at top of generic Machine-Dep chapter
6339@raisesections
6340@end ifset
6341
6342@node Reporting Bugs
6343@chapter Reporting Bugs
6344@cindex bugs in assembler
6345@cindex reporting bugs in assembler
6346
a4fb0134 6347Your bug reports play an essential role in making @command{@value{AS}} reliable.
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6348
6349Reporting a bug may help you by bringing a solution to your problem, or it may
6350not. But in any case the principal function of a bug report is to help the
a4fb0134
SC
6351entire community by making the next version of @command{@value{AS}} work better.
6352Bug reports are your contribution to the maintenance of @command{@value{AS}}.
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6353
6354In order for a bug report to serve its purpose, you must include the
6355information that enables us to fix the bug.
6356
6357@menu
6358* Bug Criteria:: Have you found a bug?
6359* Bug Reporting:: How to report bugs
6360@end menu
6361
6362@node Bug Criteria
c1253627 6363@section Have You Found a Bug?
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6364@cindex bug criteria
6365
6366If you are not sure whether you have found a bug, here are some guidelines:
6367
6368@itemize @bullet
6369@cindex fatal signal
6370@cindex assembler crash
6371@cindex crash of assembler
6372@item
6373If the assembler gets a fatal signal, for any input whatever, that is a
a4fb0134 6374@command{@value{AS}} bug. Reliable assemblers never crash.
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6375
6376@cindex error on valid input
6377@item
a4fb0134 6378If @command{@value{AS}} produces an error message for valid input, that is a bug.
252b5132
RH
6379
6380@cindex invalid input
6381@item
a4fb0134 6382If @command{@value{AS}} does not produce an error message for invalid input, that
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6383is a bug. However, you should note that your idea of ``invalid input'' might
6384be our idea of ``an extension'' or ``support for traditional practice''.
6385
6386@item
6387If you are an experienced user of assemblers, your suggestions for improvement
a4fb0134 6388of @command{@value{AS}} are welcome in any case.
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6389@end itemize
6390
6391@node Bug Reporting
c1253627 6392@section How to Report Bugs
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6393@cindex bug reports
6394@cindex assembler bugs, reporting
6395
6396A number of companies and individuals offer support for @sc{gnu} products. If
a4fb0134 6397you obtained @command{@value{AS}} from a support organization, we recommend you
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6398contact that organization first.
6399
6400You can find contact information for many support companies and
6401individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
6402distribution.
6403
a4fb0134 6404In any event, we also recommend that you send bug reports for @command{@value{AS}}
46a04e3a 6405to @samp{bug-binutils@@gnu.org}.
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6406
6407The fundamental principle of reporting bugs usefully is this:
6408@strong{report all the facts}. If you are not sure whether to state a
6409fact or leave it out, state it!
6410
6411Often people omit facts because they think they know what causes the problem
6412and assume that some details do not matter. Thus, you might assume that the
6413name of a symbol you use in an example does not matter. Well, probably it does
6414not, but one cannot be sure. Perhaps the bug is a stray memory reference which
6415happens to fetch from the location where that name is stored in memory;
6416perhaps, if the name were different, the contents of that location would fool
6417the assembler into doing the right thing despite the bug. Play it safe and
6418give a specific, complete example. That is the easiest thing for you to do,
6419and the most helpful.
6420
6421Keep in mind that the purpose of a bug report is to enable us to fix the bug if
6422it is new to us. Therefore, always write your bug reports on the assumption
6423that the bug has not been reported previously.
6424
6425Sometimes people give a few sketchy facts and ask, ``Does this ring a
c1253627
NC
6426bell?'' This cannot help us fix a bug, so it is basically useless. We
6427respond by asking for enough details to enable us to investigate.
6428You might as well expedite matters by sending them to begin with.
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6429
6430To enable us to fix the bug, you should include all these things:
6431
6432@itemize @bullet
6433@item
a4fb0134 6434The version of @command{@value{AS}}. @command{@value{AS}} announces it if you start
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6435it with the @samp{--version} argument.
6436
6437Without this, we will not know whether there is any point in looking for
a4fb0134 6438the bug in the current version of @command{@value{AS}}.
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6439
6440@item
a4fb0134 6441Any patches you may have applied to the @command{@value{AS}} source.
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6442
6443@item
6444The type of machine you are using, and the operating system name and
6445version number.
6446
6447@item
a4fb0134 6448What compiler (and its version) was used to compile @command{@value{AS}}---e.g.
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6449``@code{gcc-2.7}''.
6450
6451@item
6452The command arguments you gave the assembler to assemble your example and
6453observe the bug. To guarantee you will not omit something important, list them
6454all. A copy of the Makefile (or the output from make) is sufficient.
6455
6456If we were to try to guess the arguments, we would probably guess wrong
6457and then we might not encounter the bug.
6458
6459@item
6460A complete input file that will reproduce the bug. If the bug is observed when
6461the assembler is invoked via a compiler, send the assembler source, not the
6462high level language source. Most compilers will produce the assembler source
6463when run with the @samp{-S} option. If you are using @code{@value{GCC}}, use
6464the options @samp{-v --save-temps}; this will save the assembler source in a
6465file with an extension of @file{.s}, and also show you exactly how
a4fb0134 6466@command{@value{AS}} is being run.
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6467
6468@item
6469A description of what behavior you observe that you believe is
6470incorrect. For example, ``It gets a fatal signal.''
6471
a4fb0134 6472Of course, if the bug is that @command{@value{AS}} gets a fatal signal, then we
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6473will certainly notice it. But if the bug is incorrect output, we might not
6474notice unless it is glaringly wrong. You might as well not give us a chance to
6475make a mistake.
6476
6477Even if the problem you experience is a fatal signal, you should still say so
6478explicitly. Suppose something strange is going on, such as, your copy of
a4fb0134 6479@command{@value{AS}} is out of synch, or you have encountered a bug in the C
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6480library on your system. (This has happened!) Your copy might crash and ours
6481would not. If you told us to expect a crash, then when ours fails to crash, we
6482would know that the bug was not happening for us. If you had not told us to
6483expect a crash, then we would not be able to draw any conclusion from our
6484observations.
6485
6486@item
a4fb0134 6487If you wish to suggest changes to the @command{@value{AS}} source, send us context
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6488diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p}
6489option. Always send diffs from the old file to the new file. If you even
a4fb0134 6490discuss something in the @command{@value{AS}} source, refer to it by context, not
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6491by line number.
6492
6493The line numbers in our development sources will not match those in your
6494sources. Your line numbers would convey no useful information to us.
6495@end itemize
6496
6497Here are some things that are not necessary:
6498
6499@itemize @bullet
6500@item
6501A description of the envelope of the bug.
6502
6503Often people who encounter a bug spend a lot of time investigating
6504which changes to the input file will make the bug go away and which
6505changes will not affect it.
6506
6507This is often time consuming and not very useful, because the way we
6508will find the bug is by running a single example under the debugger
6509with breakpoints, not by pure deduction from a series of examples.
6510We recommend that you save your time for something else.
6511
6512Of course, if you can find a simpler example to report @emph{instead}
6513of the original one, that is a convenience for us. Errors in the
6514output will be easier to spot, running under the debugger will take
6515less time, and so on.
6516
6517However, simplification is not vital; if you do not want to do this,
6518report the bug anyway and send us the entire test case you used.
6519
6520@item
6521A patch for the bug.
6522
6523A patch for the bug does help us if it is a good one. But do not omit
6524the necessary information, such as the test case, on the assumption that
6525a patch is all we need. We might see problems with your patch and decide
6526to fix the problem another way, or we might not understand it at all.
6527
a4fb0134 6528Sometimes with a program as complicated as @command{@value{AS}} it is very hard to
252b5132
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6529construct an example that will make the program follow a certain path through
6530the code. If you do not send us the example, we will not be able to construct
6531one, so we will not be able to verify that the bug is fixed.
6532
6533And if we cannot understand what bug you are trying to fix, or why your
6534patch should be an improvement, we will not install it. A test case will
6535help us to understand.
6536
6537@item
6538A guess about what the bug is or what it depends on.
6539
6540Such guesses are usually wrong. Even we cannot guess right about such
6541things without first using the debugger to find the facts.
6542@end itemize
6543
6544@node Acknowledgements
6545@chapter Acknowledgements
6546
653cfe85 6547If you have contributed to GAS and your name isn't listed here,
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6548it is not meant as a slight. We just don't know about it. Send mail to the
6549maintainer, and we'll correct the situation. Currently
6550@c (January 1994),
6551the maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}).
6552
6553Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any
6554more details?}
6555
6556Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug
6557information and the 68k series machines, most of the preprocessing pass, and
6558extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}.
6559
6560K. Richard Pixley maintained GAS for a while, adding various enhancements and
6561many bug fixes, including merging support for several processors, breaking GAS
6562up to handle multiple object file format back ends (including heavy rewrite,
6563testing, an integration of the coff and b.out back ends), adding configuration
6564including heavy testing and verification of cross assemblers and file splits
6565and renaming, converted GAS to strictly ANSI C including full prototypes, added
6566support for m680[34]0 and cpu32, did considerable work on i960 including a COFF
6567port (including considerable amounts of reverse engineering), a SPARC opcode
6568file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know''
6569assertions and made them work, much other reorganization, cleanup, and lint.
6570
6571Ken Raeburn wrote the high-level BFD interface code to replace most of the code
6572in format-specific I/O modules.
6573
6574The original VMS support was contributed by David L. Kashtan. Eric Youngdale
6575has done much work with it since.
6576
6577The Intel 80386 machine description was written by Eliot Dresselhaus.
6578
6579Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
6580
6581The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
6582University and Torbjorn Granlund of the Swedish Institute of Computer Science.
6583
6584Keith Knowles at the Open Software Foundation wrote the original MIPS back end
6585(@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support
6586(which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to
6587support a.out format.
6588
7be1c489
AM
6589Support for the Zilog Z8k and Renesas H8/300 processors (tc-z8k,
6590tc-h8300), and IEEE 695 object file format (obj-ieee), was written by
252b5132
RH
6591Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
6592use BFD for some low-level operations, for use with the H8/300 and AMD 29k
6593targets.
6594
6595John Gilmore built the AMD 29000 support, added @code{.include} support, and
6596simplified the configuration of which versions accept which directives. He
6597updated the 68k machine description so that Motorola's opcodes always produced
c1253627 6598fixed-size instructions (e.g., @code{jsr}), while synthetic instructions
252b5132
RH
6599remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested
6600cross-compilation support, and one bug in relaxation that took a week and
6601required the proverbial one-bit fix.
6602
6603Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the
660468k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
6605added support for MIPS ECOFF and ELF targets, wrote the initial RS/6000 and
6606PowerPC assembler, and made a few other minor patches.
6607
653cfe85 6608Steve Chamberlain made GAS able to generate listings.
252b5132
RH
6609
6610Hewlett-Packard contributed support for the HP9000/300.
6611
6612Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM)
6613along with a fairly extensive HPPA testsuite (for both SOM and ELF object
6614formats). This work was supported by both the Center for Software Science at
6615the University of Utah and Cygnus Support.
6616
6617Support for ELF format files has been worked on by Mark Eichin of Cygnus
6618Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
6619Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
6620Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
6621and some initial 64-bit support).
6622
c1253627 6623Linas Vepstas added GAS support for the ESA/390 ``IBM 370'' architecture.
5b93d8bb 6624
252b5132
RH
6625Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote GAS and BFD
6626support for openVMS/Alpha.
6627
39bec121
TW
6628Timothy Wall, Michael Hayes, and Greg Smart contributed to the various tic*
6629flavors.
6630
e0001a05
NC
6631David Heine, Sterling Augustine, Bob Wilson and John Ruttenberg from Tensilica,
6632Inc. added support for Xtensa processors.
6633
252b5132
RH
6634Several engineers at Cygnus Support have also provided many small bug fixes and
6635configuration enhancements.
6636
6637Many others have contributed large or small bugfixes and enhancements. If
6638you have contributed significant work and are not mentioned on this list, and
6639want to be, let us know. Some of the history has been lost; we are not
6640intentionally leaving anyone out.
6641
c1253627 6642@include fdl.texi
cf055d54 6643
252b5132
RH
6644@node Index
6645@unnumbered Index
6646
6647@printindex cp
6648
6649@contents
6650@bye
6651@c Local Variables:
6652@c fill-column: 79
6653@c End:
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