Commit | Line | Data |
---|---|---|
66b818fb | 1 | \input texinfo @c -*-Texinfo-*- |
4d32706e | 2 | @c Copyright (c) 1991, 92, 93, 94, 95, 96, 1997 Free Software Foundation, Inc. |
e680d737 RP |
3 | @c UPDATE!! On future updates-- |
4 | @c (1) check for new machine-dep cmdline options in | |
5 | @c md_parse_option definitions in config/tc-*.c | |
6 | @c (2) for platform-specific directives, examine md_pseudo_op | |
7 | @c in config/tc-*.c | |
8 | @c (3) for object-format specific directives, examine obj_pseudo_op | |
9 | @c in config/obj-*.c | |
10 | @c (4) portable directives in potable[] in read.c | |
f009d0ab RP |
11 | @c %**start of header |
12 | @setfilename as.info | |
13 | @c ---config--- | |
14 | @c defaults, config file may override: | |
15 | @set have-stabs | |
16 | @c --- | |
4b9f4409 | 17 | @include asconfig.texi |
f009d0ab RP |
18 | @c --- |
19 | @c common OR combinations of conditions | |
20 | @ifset AOUT | |
21 | @set aout-bout | |
22 | @end ifset | |
3ffb03b1 DE |
23 | @ifset ARM/Thumb |
24 | @set ARM | |
25 | @end ifset | |
f009d0ab RP |
26 | @ifset BOUT |
27 | @set aout-bout | |
28 | @end ifset | |
29 | @ifset H8/300 | |
30 | @set H8 | |
31 | @end ifset | |
32 | @ifset H8/500 | |
33 | @set H8 | |
34 | @end ifset | |
f009d0ab RP |
35 | @ifset SH |
36 | @set H8 | |
37 | @end ifset | |
9dcf8057 JL |
38 | @ifset HPPA |
39 | @set abnormal-separator | |
40 | @end ifset | |
f009d0ab RP |
41 | @c ------------ |
42 | @ifset GENERIC | |
43 | @settitle Using @value{AS} | |
44 | @end ifset | |
45 | @ifclear GENERIC | |
46 | @settitle Using @value{AS} (@value{TARGET}) | |
47 | @end ifclear | |
66b818fb | 48 | @setchapternewpage odd |
66b818fb RP |
49 | @c %**end of header |
50 | ||
fb5bec49 RP |
51 | @c @smallbook |
52 | @c @set SMALL | |
53 | @c WARE! Some of the machine-dependent sections contain tables of machine | |
54 | @c instructions. Except in multi-column format, these tables look silly. | |
55 | @c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so | |
56 | @c the multi-col format is faked within @example sections. | |
57 | @c | |
58 | @c Again unfortunately, the natural size that fits on a page, for these tables, | |
59 | @c is different depending on whether or not smallbook is turned on. | |
60 | @c This matters, because of order: text flow switches columns at each page | |
61 | @c break. | |
62 | @c | |
63 | @c The format faked in this source works reasonably well for smallbook, | |
64 | @c not well for the default large-page format. This manual expects that if you | |
65 | @c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the | |
66 | @c tables in question. You can turn on one without the other at your | |
67 | @c discretion, of course. | |
68 | @ifinfo | |
69 | @set SMALL | |
70 | @c the insn tables look just as silly in info files regardless of smallbook, | |
71 | @c might as well show 'em anyways. | |
72 | @end ifinfo | |
73 | ||
80381063 RP |
74 | @ifinfo |
75 | @format | |
dd565f85 RP |
76 | START-INFO-DIR-ENTRY |
77 | * As: (as). The GNU assembler. | |
78 | END-INFO-DIR-ENTRY | |
80381063 RP |
79 | @end format |
80 | @end ifinfo | |
81 | ||
66b818fb RP |
82 | @finalout |
83 | @syncodeindex ky cp | |
84 | ||
47342e8f | 85 | @ifinfo |
f009d0ab | 86 | This file documents the GNU Assembler "@value{AS}". |
47342e8f | 87 | |
4d32706e | 88 | Copyright (C) 1991, 92, 93, 94, 95, 96, 1997 Free Software Foundation, Inc. |
47342e8f RP |
89 | |
90 | Permission is granted to make and distribute verbatim copies of | |
91 | this manual provided the copyright notice and this permission notice | |
92 | are preserved on all copies. | |
93 | ||
94 | @ignore | |
95 | Permission is granted to process this file through Tex and print the | |
96 | results, provided the printed document carries copying permission | |
97 | notice identical to this one except for the removal of this paragraph | |
98 | (this paragraph not being relevant to the printed manual). | |
99 | ||
100 | @end ignore | |
81fcb3ff RP |
101 | Permission is granted to copy and distribute modified versions of this manual |
102 | under the conditions for verbatim copying, provided that the entire resulting | |
103 | derived work is distributed under the terms of a permission notice identical to | |
104 | this one. | |
47342e8f RP |
105 | |
106 | Permission is granted to copy and distribute translations of this manual | |
81fcb3ff | 107 | into another language, under the above conditions for modified versions. |
47342e8f | 108 | @end ifinfo |
66b818fb | 109 | |
93b45514 | 110 | @titlepage |
f009d0ab | 111 | @title Using @value{AS} |
71dd3c40 | 112 | @subtitle The @sc{gnu} Assembler |
f009d0ab RP |
113 | @ifclear GENERIC |
114 | @subtitle for the @value{TARGET} family | |
115 | @end ifclear | |
93b45514 | 116 | @sp 1 |
e680d737 | 117 | @subtitle January 1994 |
0b5b143a | 118 | @sp 1 |
93b45514 RP |
119 | @sp 13 |
120 | The Free Software Foundation Inc. thanks The Nice Computer | |
121 | Company of Australia for loaning Dean Elsner to write the | |
71dd3c40 | 122 | first (Vax) version of @code{as} for Project @sc{gnu}. |
93b45514 RP |
123 | The proprietors, management and staff of TNCCA thank FSF for |
124 | distracting the boss while they got some work | |
125 | done. | |
126 | @sp 3 | |
7d7ecbdd | 127 | @author Dean Elsner, Jay Fenlason & friends |
47342e8f RP |
128 | @page |
129 | @tex | |
47342e8f | 130 | {\parskip=0pt |
f009d0ab | 131 | \hfill {\it Using {\tt @value{AS}}}\par |
71dd3c40 | 132 | \hfill Edited by Cygnus Support\par |
47342e8f | 133 | } |
b50e59fe RP |
134 | %"boxit" macro for figures: |
135 | %Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3) | |
136 | \gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt | |
137 | \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil | |
138 | #2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline | |
139 | \gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box | |
47342e8f | 140 | @end tex |
93b45514 | 141 | |
47342e8f | 142 | @vskip 0pt plus 1filll |
4d32706e | 143 | Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 1997 Free Software Foundation, Inc. |
93b45514 RP |
144 | |
145 | Permission is granted to make and distribute verbatim copies of | |
146 | this manual provided the copyright notice and this permission notice | |
147 | are preserved on all copies. | |
148 | ||
81fcb3ff RP |
149 | Permission is granted to copy and distribute modified versions of this manual |
150 | under the conditions for verbatim copying, provided that the entire resulting | |
151 | derived work is distributed under the terms of a permission notice identical to | |
152 | this one. | |
93b45514 RP |
153 | |
154 | Permission is granted to copy and distribute translations of this manual | |
81fcb3ff | 155 | into another language, under the above conditions for modified versions. |
93b45514 | 156 | @end titlepage |
f009d0ab | 157 | |
d0281557 | 158 | @ifinfo |
242d9c06 | 159 | @node Top |
f009d0ab | 160 | @top Using @value{AS} |
242d9c06 | 161 | |
8babef85 | 162 | This file is a user guide to the @sc{gnu} assembler @code{@value{AS}}. |
f009d0ab RP |
163 | @ifclear GENERIC |
164 | This version of the file describes @code{@value{AS}} configured to generate | |
165 | code for @value{TARGET} architectures. | |
166 | @end ifclear | |
7a4c8e5c | 167 | @menu |
ba487f3a RP |
168 | * Overview:: Overview |
169 | * Invoking:: Command-Line Options | |
170 | * Syntax:: Syntax | |
171 | * Sections:: Sections and Relocation | |
172 | * Symbols:: Symbols | |
173 | * Expressions:: Expressions | |
174 | * Pseudo Ops:: Assembler Directives | |
f009d0ab | 175 | * Machine Dependencies:: Machine Dependent Features |
9a5acea8 | 176 | * Reporting Bugs:: Reporting Bugs |
9dcf8057 | 177 | * Acknowledgements:: Who Did What |
66b818fb | 178 | * Index:: Index |
7a4c8e5c | 179 | @end menu |
242d9c06 | 180 | @end ifinfo |
7a4c8e5c | 181 | |
242d9c06 | 182 | @node Overview |
b50e59fe | 183 | @chapter Overview |
d0281557 | 184 | @iftex |
8babef85 | 185 | This manual is a user guide to the @sc{gnu} assembler @code{@value{AS}}. |
f009d0ab RP |
186 | @ifclear GENERIC |
187 | This version of the manual describes @code{@value{AS}} configured to generate | |
188 | code for @value{TARGET} architectures. | |
189 | @end ifclear | |
d0281557 | 190 | @end iftex |
b50e59fe | 191 | |
66b818fb RP |
192 | @cindex invocation summary |
193 | @cindex option summary | |
194 | @cindex summary of options | |
f009d0ab | 195 | Here is a brief summary of how to invoke @code{@value{AS}}. For details, |
7a4c8e5c | 196 | @pxref{Invoking,,Comand-Line Options}. |
b50e59fe | 197 | |
7d7ecbdd | 198 | @c We don't use deffn and friends for the following because they seem |
b50e59fe | 199 | @c to be limited to one line for the header. |
d0281557 | 200 | @smallexample |
35cfacf0 | 201 | @value{AS} [ -a[cdhlns][=file] ] [ -D ] [ --defsym @var{sym}=@var{val} ] |
cd924033 | 202 | [ -f ] [ --gstabs ] [ --help ] [ -I @var{dir} ] [ -J ] [ -K ] [ -L ] |
71dd3c40 ILT |
203 | [ -o @var{objfile} ] [ -R ] [ --statistics ] [ -v ] [ -version ] |
204 | [ --version ] [ -W ] [ -w ] [ -x ] [ -Z ] | |
f009d0ab | 205 | @ifset A29K |
2d8e0f62 | 206 | @c am29k has no machine-dependent assembler options |
f009d0ab | 207 | @end ifset |
99c4053d KR |
208 | @ifset ARC |
209 | [ -mbig-endian | -mlittle-endian ] | |
210 | @end ifset | |
3ffb03b1 DE |
211 | @ifset ARM |
212 | [ -m[arm]1 | -m[arm]2 | -m[arm]250 | -m[arm]3 | -m[arm]6 | -m[arm]7[t][[d]m[i]] ] | |
213 | [ -m[arm]v2 | -m[arm]v2a | -m[arm]v3 | -m[arm]v3m | -m[arm]v4 | -m[arm]v4t ] | |
214 | [ -mthumb | -mall ] | |
215 | [ -mfpa10 | -mfpa11 | -mfpe-old | -mno-fpu ] | |
216 | [ -EB | -EL ] | |
217 | [ -mapcs-32 | -mapcs-26 ] | |
218 | @end ifset | |
9a5acea8 ILT |
219 | @ifset D10V |
220 | [ -O ] | |
221 | @end ifset | |
9a5acea8 | 222 | |
f009d0ab RP |
223 | @ifset H8 |
224 | @c Hitachi family chips have no machine-dependent assembler options | |
225 | @end ifset | |
9dcf8057 JL |
226 | @ifset HPPA |
227 | @c HPPA has no machine-dependent assembler options (yet). | |
228 | @end ifset | |
f009d0ab | 229 | @ifset SPARC |
71dd3c40 | 230 | @c The order here is important. See c-sparc.texi. |
c6c7035c | 231 | [ -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite | -Av9 | -Av9a ] |
71dd3c40 | 232 | [ -xarch=v8plus | -xarch=v8plusa ] [ -bump ] |
f009d0ab RP |
233 | @end ifset |
234 | @ifset Z8000 | |
2d8e0f62 | 235 | @c Z8000 has no machine-dependent assembler options |
f009d0ab RP |
236 | @end ifset |
237 | @ifset I960 | |
9ebc250f | 238 | @c see md_parse_option in tc-i960.c |
81fcb3ff | 239 | [ -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC ] |
b3b2623c | 240 | [ -b ] [ -no-relax ] |
f009d0ab RP |
241 | @end ifset |
242 | @ifset M680X0 | |
81fcb3ff | 243 | [ -l ] [ -m68000 | -m68010 | -m68020 | ... ] |
34214344 KR |
244 | @end ifset |
245 | @ifset MIPS | |
b3b2623c KR |
246 | [ -nocpp ] [ -EL ] [ -EB ] [ -G @var{num} ] [ -mcpu=@var{CPU} ] |
247 | [ -mips1 ] [ -mips2 ] [ -mips3 ] [ -m4650 ] [ -no-m4650 ] | |
dd565f85 | 248 | [ --trap ] [ --break ] |
ba5ceb30 | 249 | [ --emulation=@var{name} ] |
f009d0ab | 250 | @end ifset |
81fcb3ff | 251 | [ -- | @var{files} @dots{} ] |
d0281557 | 252 | @end smallexample |
47342e8f RP |
253 | |
254 | @table @code | |
0193302d | 255 | @item -a[dhlns] |
05a0e43b RP |
256 | Turn on listings, in any of a variety of ways: |
257 | ||
258 | @table @code | |
259 | @item -ad | |
b3b2623c | 260 | omit debugging directives |
05a0e43b RP |
261 | |
262 | @item -ah | |
263 | include high-level source | |
264 | ||
265 | @item -al | |
b3b2623c | 266 | include assembly |
05a0e43b RP |
267 | |
268 | @item -an | |
b3b2623c | 269 | omit forms processing |
05a0e43b RP |
270 | |
271 | @item -as | |
b3b2623c | 272 | include symbols |
85a961c6 ILT |
273 | |
274 | @item =file | |
275 | set the name of the listing file | |
05a0e43b RP |
276 | @end table |
277 | ||
278 | You may combine these options; for example, use @samp{-aln} for assembly | |
85a961c6 ILT |
279 | listing without forms processing. The @samp{=file} option, if used, must be |
280 | the last one. By itself, @samp{-a} defaults to @samp{-ahls}---that is, all | |
281 | listings turned on. | |
b50e59fe RP |
282 | |
283 | @item -D | |
b3b2623c KR |
284 | Ignored. This option is accepted for script compatibility with calls to |
285 | other assemblers. | |
b50e59fe | 286 | |
71dd3c40 ILT |
287 | @item --defsym @var{sym}=@var{value} |
288 | Define the symbol @var{sym} to be @var{value} before assembling the input file. | |
289 | @var{value} must be an integer constant. As in C, a leading @samp{0x} | |
290 | indicates a hexadecimal value, and a leading @samp{0} indicates an octal value. | |
291 | ||
47342e8f | 292 | @item -f |
9dcf8057 | 293 | ``fast''---skip whitespace and comment preprocessing (assume source is |
b3b2623c | 294 | compiler output). |
47342e8f | 295 | |
cd924033 ILT |
296 | @item --gstabs |
297 | Generate stabs debugging information for each assembler line. This | |
298 | may help debugging assembler code, if the debugger can handle it. | |
299 | ||
b3b2623c KR |
300 | @item --help |
301 | Print a summary of the command line options and exit. | |
302 | ||
303 | @item -I @var{dir} | |
304 | Add directory @var{dir} to the search list for @code{.include} directives. | |
305 | ||
306 | @item -J | |
307 | Don't warn about signed overflow. | |
b50e59fe | 308 | |
80381063 | 309 | @item -K |
f009d0ab RP |
310 | @ifclear DIFF-TBL-KLUGE |
311 | This option is accepted but has no effect on the @value{TARGET} family. | |
312 | @end ifclear | |
313 | @ifset DIFF-TBL-KLUGE | |
0b5b143a | 314 | Issue warnings when difference tables altered for long displacements. |
f009d0ab | 315 | @end ifset |
47342e8f RP |
316 | |
317 | @item -L | |
b3b2623c | 318 | Keep (in the symbol table) local symbols, starting with @samp{L}. |
47342e8f RP |
319 | |
320 | @item -o @var{objfile} | |
b3b2623c | 321 | Name the object-file output from @code{@value{AS}} @var{objfile}. |
47342e8f RP |
322 | |
323 | @item -R | |
b3b2623c | 324 | Fold the data section into the text section. |
47342e8f | 325 | |
62e59d28 | 326 | @item --statistics |
b3b2623c | 327 | Print the maximum space (in bytes) and total time (in seconds) used by |
62e59d28 RP |
328 | assembly. |
329 | ||
7d7ecbdd | 330 | @item -v |
b3b2623c KR |
331 | @itemx -version |
332 | Print the @code{as} version. | |
333 | ||
334 | @item --version | |
335 | Print the @code{as} version and exit. | |
7d7ecbdd | 336 | |
47342e8f | 337 | @item -W |
b3b2623c KR |
338 | Suppress warning messages. |
339 | ||
340 | @item -w | |
341 | Ignored. | |
342 | ||
343 | @item -x | |
344 | Ignored. | |
47342e8f | 345 | |
62e59d28 | 346 | @item -Z |
b3b2623c | 347 | Generate an object file even after errors. |
62e59d28 | 348 | |
9ebc250f KR |
349 | @item -- | @var{files} @dots{} |
350 | Standard input, or source files to assemble. | |
9ebc250f KR |
351 | |
352 | @end table | |
353 | ||
99c4053d KR |
354 | @ifset ARC |
355 | The following options are available when @value{AS} is configured for | |
356 | an ARC processor. | |
357 | ||
358 | @table @code | |
359 | ||
360 | @cindex ARC endianness | |
361 | @cindex endianness, ARC | |
362 | @cindex big endian output, ARC | |
363 | @item -mbig-endian | |
364 | Generate ``big endian'' format output. | |
365 | ||
366 | @cindex little endian output, ARC | |
367 | @item -mlittle-endian | |
368 | Generate ``little endian'' format output. | |
369 | ||
370 | @end table | |
371 | @end ifset | |
372 | ||
3ffb03b1 DE |
373 | @ifset ARM |
374 | The following options are available when @value{AS} is configured for the ARM | |
375 | processor family. | |
376 | ||
377 | @table @code | |
378 | @item -m[arm]1 | -m[arm]2 | -m[arm]250 | -m[arm]3 | -m[arm]6 | -m[arm]7[t][[d]m] | -m[arm]v2 | -m[arm]v2a | -m[arm]v3 | -m[arm]v3m | -m[arm]v4 | -m[arm]v4t | |
379 | Specify which variant of the ARM architecture is the target. | |
380 | @item -mthumb | -mall | |
381 | Enable or disable Thumb only instruction decoding. | |
382 | @item -mfpa10 | -mfpa11 | -mfpe-old | -mno-fpu | |
383 | Select which Floating Point architcture is the target. | |
384 | @item -mapcs-32 | -mapcs-26 | |
385 | Select which procedure calling convention is in use. | |
386 | @item -EB | -EL | |
387 | Select either big-endian (-EB) or little-endian (-EL) output. | |
388 | @end table | |
389 | @end ifset | |
390 | ||
9a5acea8 ILT |
391 | @ifset D10V |
392 | The following options are available when @value{AS} is configured for | |
393 | a D10V processor. | |
394 | @table @code | |
395 | @cindex D10V optimization | |
396 | @cindex optimization, D10V | |
397 | @item -O | |
398 | Optimize output by parallelizing instructions. | |
399 | @end table | |
400 | @end ifset | |
9a5acea8 | 401 | |
f009d0ab RP |
402 | @ifset I960 |
403 | The following options are available when @value{AS} is configured for the | |
9ebc250f KR |
404 | Intel 80960 processor. |
405 | ||
406 | @table @code | |
d0281557 RP |
407 | @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC |
408 | Specify which variant of the 960 architecture is the target. | |
409 | ||
410 | @item -b | |
411 | Add code to collect statistics about branches taken. | |
412 | ||
b3b2623c | 413 | @item -no-relax |
66b818fb | 414 | Do not alter compare-and-branch instructions for long displacements; |
d0281557 | 415 | error if necessary. |
9ebc250f KR |
416 | |
417 | @end table | |
f009d0ab | 418 | @end ifset |
d0281557 | 419 | |
f009d0ab RP |
420 | @ifset M680X0 |
421 | The following options are available when @value{AS} is configured for the | |
9ebc250f KR |
422 | Motorola 68000 series. |
423 | ||
424 | @table @code | |
425 | ||
09352a5d | 426 | @item -l |
9ebc250f | 427 | Shorten references to undefined symbols, to one word instead of two. |
09352a5d | 428 | |
910d7df2 C |
429 | @item -m68000 | -m68008 | -m68010 | -m68020 | -m68030 | -m68040 | -m68060 |
430 | @itemx | -m68302 | -m68331 | -m68332 | -m68333 | -m68340 | -mcpu32 | -m5200 | |
9ebc250f KR |
431 | Specify what processor in the 68000 family is the target. The default |
432 | is normally the 68020, but this can be changed at configuration time. | |
433 | ||
434 | @item -m68881 | -m68882 | -mno-68881 | -mno-68882 | |
435 | The target machine does (or does not) have a floating-point coprocessor. | |
436 | The default is to assume a coprocessor for 68020, 68030, and cpu32. Although | |
437 | the basic 68000 is not compatible with the 68881, a combination of the | |
438 | two can be specified, since it's possible to do emulation of the | |
439 | coprocessor instructions with the main processor. | |
440 | ||
441 | @item -m68851 | -mno-68851 | |
442 | The target machine does (or does not) have a memory-management | |
443 | unit coprocessor. The default is to assume an MMU for 68020 and up. | |
47342e8f | 444 | |
47342e8f | 445 | @end table |
f009d0ab RP |
446 | @end ifset |
447 | ||
448 | @ifset SPARC | |
449 | The following options are available when @code{@value{AS}} is configured | |
450 | for the SPARC architecture: | |
451 | ||
452 | @table @code | |
c6c7035c | 453 | @item -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite | -Av9 | -Av9a |
f009d0ab RP |
454 | Explicitly select a variant of the SPARC architecture. |
455 | ||
71dd3c40 ILT |
456 | @item -xarch=v8plus | -xarch=v8plusa |
457 | For compatibility with the Solaris v9 assembler. These options are | |
458 | equivalent to -Av9 and -Av9a, respectively. | |
459 | ||
f009d0ab RP |
460 | @item -bump |
461 | Warn when the assembler switches to another architecture. | |
462 | @end table | |
463 | @end ifset | |
47342e8f | 464 | |
34214344 KR |
465 | @ifset MIPS |
466 | The following options are available when @value{AS} is configured for | |
dd565f85 | 467 | a MIPS processor. |
34214344 KR |
468 | |
469 | @table @code | |
34214344 | 470 | @item -G @var{num} |
05a0e43b | 471 | This option sets the largest size of an object that can be referenced |
dd565f85 RP |
472 | implicitly with the @code{gp} register. It is only accepted for targets that |
473 | use ECOFF format, such as a DECstation running Ultrix. The default value is 8. | |
34214344 | 474 | |
05a0e43b RP |
475 | @cindex MIPS endianness |
476 | @cindex endianness, MIPS | |
05a0e43b | 477 | @cindex big endian output, MIPS |
dd565f85 | 478 | @item -EB |
05a0e43b RP |
479 | Generate ``big endian'' format output. |
480 | ||
05a0e43b | 481 | @cindex little endian output, MIPS |
dd565f85 | 482 | @item -EL |
05a0e43b | 483 | Generate ``little endian'' format output. |
34214344 | 484 | |
1051c97f ILT |
485 | @cindex MIPS ISA |
486 | @item -mips1 | |
dd565f85 RP |
487 | @itemx -mips2 |
488 | @itemx -mips3 | |
489 | Generate code for a particular MIPS Instruction Set Architecture level. | |
490 | @samp{-mips1} corresponds to the @sc{r2000} and @sc{r3000} processors, | |
491 | @samp{-mips2} to the @sc{r6000} processor, and @samp{-mips3} to the @sc{r4000} | |
492 | processor. | |
1051c97f | 493 | |
b3b2623c KR |
494 | @item -m4650 |
495 | @item -no-m4650 | |
496 | Generate code for the MIPS @sc{r4650} chip. This tells the assembler to accept | |
497 | the @samp{mad} and @samp{madu} instruction, and to not schedule @samp{nop} | |
498 | instructions around accesses to the @samp{HI} and @samp{LO} registers. | |
499 | @samp{-no-m4650} turns off this option. | |
500 | ||
501 | @item -mcpu=@var{CPU} | |
502 | Generate code for a particular MIPS cpu. This has little effect on the | |
503 | assembler, but it is passed by @code{@value{GCC}}. | |
504 | ||
ba5ceb30 KR |
505 | @cindex emulation |
506 | @item --emulation=@var{name} | |
3ffb03b1 | 507 | This option causes @code{@value{AS}} to emulate @code{@value{AS}} configured |
ba5ceb30 KR |
508 | for some other target, in all respects, including output format (choosing |
509 | between ELF and ECOFF only), handling of pseudo-opcodes which may generate | |
510 | debugging information or store symbol table information, and default | |
511 | endianness. The available configuration names are: @samp{mipsecoff}, | |
512 | @samp{mipself}, @samp{mipslecoff}, @samp{mipsbecoff}, @samp{mipslelf}, | |
513 | @samp{mipsbelf}. The first two do not alter the default endianness from that | |
514 | of the primary target for which the assembler was configured; the others change | |
515 | the default to little- or big-endian as indicated by the @samp{b} or @samp{l} | |
516 | in the name. Using @samp{-EB} or @samp{-EL} will override the endianness | |
517 | selection in any case. | |
518 | ||
519 | This option is currently supported only when the primary target | |
520 | @code{@value{AS}} is configured for is a MIPS ELF or ECOFF target. | |
521 | Furthermore, the primary target or others specified with | |
522 | @samp{--enable-targets=@dots{}} at configuration time must include support for | |
523 | the other format, if both are to be available. For example, the Irix 5 | |
524 | configuration includes support for both. | |
525 | ||
526 | Eventually, this option will support more configurations, with more | |
527 | fine-grained control over the assembler's behavior, and will be supported for | |
528 | more processors. | |
529 | ||
05a0e43b | 530 | @item -nocpp |
dd565f85 RP |
531 | @code{@value{AS}} ignores this option. It is accepted for compatibility with |
532 | the native tools. | |
533 | ||
71dd3c40 | 534 | @need 900 |
dd565f85 RP |
535 | @item --trap |
536 | @itemx --no-trap | |
537 | @itemx --break | |
538 | @itemx --no-break | |
539 | Control how to deal with multiplication overflow and division by zero. | |
540 | @samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception | |
541 | (and only work for Instruction Set Architecture level 2 and higher); | |
542 | @samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a | |
543 | break exception. | |
34214344 KR |
544 | @end table |
545 | @end ifset | |
546 | ||
7a4c8e5c | 547 | @menu |
ba487f3a | 548 | * Manual:: Structure of this Manual |
3ffb03b1 | 549 | * GNU Assembler:: The GNU Assembler |
ba487f3a RP |
550 | * Object Formats:: Object File Formats |
551 | * Command Line:: Command Line | |
552 | * Input Files:: Input Files | |
553 | * Object:: Output (Object) File | |
554 | * Errors:: Error and Warning Messages | |
7a4c8e5c RP |
555 | @end menu |
556 | ||
242d9c06 | 557 | @node Manual |
d0281557 | 558 | @section Structure of this Manual |
66b818fb RP |
559 | |
560 | @cindex manual, structure and purpose | |
561 | This manual is intended to describe what you need to know to use | |
f009d0ab | 562 | @sc{gnu} @code{@value{AS}}. We cover the syntax expected in source files, including |
47342e8f | 563 | notation for symbols, constants, and expressions; the directives that |
f009d0ab | 564 | @code{@value{AS}} understands; and of course how to invoke @code{@value{AS}}. |
47342e8f | 565 | |
f009d0ab RP |
566 | @ifclear GENERIC |
567 | We also cover special features in the @value{TARGET} | |
568 | configuration of @code{@value{AS}}, including assembler directives. | |
569 | @end ifclear | |
570 | @ifset GENERIC | |
66b818fb | 571 | This manual also describes some of the machine-dependent features of |
09352a5d | 572 | various flavors of the assembler. |
f009d0ab | 573 | @end ifset |
93b45514 | 574 | |
66b818fb | 575 | @cindex machine instructions (not covered) |
47342e8f | 576 | On the other hand, this manual is @emph{not} intended as an introduction |
b50e59fe RP |
577 | to programming in assembly language---let alone programming in general! |
578 | In a similar vein, we make no attempt to introduce the machine | |
47342e8f RP |
579 | architecture; we do @emph{not} describe the instruction set, standard |
580 | mnemonics, registers or addressing modes that are standard to a | |
f009d0ab RP |
581 | particular architecture. |
582 | @ifset GENERIC | |
66b818fb | 583 | You may want to consult the manufacturer's |
b50e59fe | 584 | machine architecture manual for this information. |
f009d0ab RP |
585 | @end ifset |
586 | @ifclear GENERIC | |
587 | @ifset H8/300 | |
66b818fb | 588 | For information on the H8/300 machine instruction set, see @cite{H8/300 |
8d8ddccb RP |
589 | Series Programming Manual} (Hitachi ADE--602--025). For the H8/300H, |
590 | see @cite{H8/300H Series Programming Manual} (Hitachi). | |
f009d0ab RP |
591 | @end ifset |
592 | @ifset H8/500 | |
593 | For information on the H8/500 machine instruction set, see @cite{H8/500 | |
594 | Series Programming Manual} (Hitachi M21T001). | |
595 | @end ifset | |
f009d0ab RP |
596 | @ifset SH |
597 | For information on the Hitachi SH machine instruction set, see | |
598 | @cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.). | |
599 | @end ifset | |
f009d0ab | 600 | @ifset Z8000 |
2d8e0f62 | 601 | For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual} |
f009d0ab RP |
602 | @end ifset |
603 | @end ifclear | |
93b45514 | 604 | |
71dd3c40 | 605 | @c I think this is premature---doc@cygnus.com, 17jan1991 |
47342e8f | 606 | @ignore |
66b818fb | 607 | Throughout this manual, we assume that you are running @dfn{GNU}, |
93b45514 RP |
608 | the portable operating system from the @dfn{Free Software |
609 | Foundation, Inc.}. This restricts our attention to certain kinds of | |
8babef85 | 610 | computer (in particular, the kinds of computers that @sc{gnu} can run on); |
93b45514 RP |
611 | once this assumption is granted examples and definitions need less |
612 | qualification. | |
613 | ||
f009d0ab | 614 | @code{@value{AS}} is part of a team of programs that turn a high-level |
93b45514 RP |
615 | human-readable series of instructions into a low-level |
616 | computer-readable series of instructions. Different versions of | |
f009d0ab | 617 | @code{@value{AS}} are used for different kinds of computer. |
47342e8f | 618 | @end ignore |
93b45514 | 619 | |
b50e59fe RP |
620 | @c There used to be a section "Terminology" here, which defined |
621 | @c "contents", "byte", "word", and "long". Defining "word" to any | |
622 | @c particular size is confusing when the .word directive may generate 16 | |
623 | @c bits on one machine and 32 bits on another; in general, for the user | |
624 | @c version of this manual, none of these terms seem essential to define. | |
625 | @c They were used very little even in the former draft of the manual; | |
626 | @c this draft makes an effort to avoid them (except in names of | |
d0281557 RP |
627 | @c directives). |
628 | ||
242d9c06 | 629 | @node GNU Assembler |
3ffb03b1 | 630 | @section The GNU Assembler |
66b818fb | 631 | |
8babef85 | 632 | @sc{gnu} @code{as} is really a family of assemblers. |
f009d0ab RP |
633 | @ifclear GENERIC |
634 | This manual describes @code{@value{AS}}, a member of that family which is | |
635 | configured for the @value{TARGET} architectures. | |
636 | @end ifclear | |
8babef85 | 637 | If you use (or have used) the @sc{gnu} assembler on one architecture, you |
7a4c8e5c RP |
638 | should find a fairly similar environment when you use it on another |
639 | architecture. Each version has much in common with the others, | |
640 | including object file formats, most assembler directives (often called | |
9ebc250f | 641 | @dfn{pseudo-ops}) and assembler syntax.@refill |
d0281557 | 642 | |
3ffb03b1 | 643 | @cindex purpose of @sc{gnu} assembler |
f009d0ab | 644 | @code{@value{AS}} is primarily intended to assemble the output of the |
8babef85 | 645 | @sc{gnu} C compiler @code{@value{GCC}} for use by the linker |
f009d0ab RP |
646 | @code{@value{LD}}. Nevertheless, we've tried to make @code{@value{AS}} |
647 | assemble correctly everything that other assemblers for the same | |
648 | machine would assemble. | |
649 | @ifset VAX | |
650 | Any exceptions are documented explicitly (@pxref{Machine Dependencies}). | |
651 | @end ifset | |
652 | @ifset M680X0 | |
653 | @c This remark should appear in generic version of manual; assumption | |
654 | @c here is that generic version sets M680x0. | |
655 | This doesn't mean @code{@value{AS}} always uses the same syntax as another | |
b50e59fe RP |
656 | assembler for the same architecture; for example, we know of several |
657 | incompatible versions of 680x0 assembly language syntax. | |
f009d0ab | 658 | @end ifset |
47342e8f | 659 | |
f009d0ab | 660 | Unlike older assemblers, @code{@value{AS}} is designed to assemble a source |
b50e59fe | 661 | program in one pass of the source file. This has a subtle impact on the |
7a4c8e5c | 662 | @kbd{.org} directive (@pxref{Org,,@code{.org}}). |
93b45514 | 663 | |
242d9c06 | 664 | @node Object Formats |
d0281557 | 665 | @section Object File Formats |
66b818fb RP |
666 | |
667 | @cindex object file format | |
8babef85 | 668 | The @sc{gnu} assembler can be configured to produce several alternative |
7d7ecbdd RP |
669 | object file formats. For the most part, this does not affect how you |
670 | write assembly language programs; but directives for debugging symbols | |
671 | are typically different in different file formats. @xref{Symbol | |
672 | Attributes,,Symbol Attributes}. | |
f009d0ab RP |
673 | @ifclear GENERIC |
674 | @ifclear MULTI-OBJ | |
675 | On the @value{TARGET}, @code{@value{AS}} is configured to produce | |
676 | @value{OBJ-NAME} format object files. | |
677 | @end ifclear | |
678 | @c The following should exhaust all configs that set MULTI-OBJ, ideally | |
679 | @ifset A29K | |
680 | On the @value{TARGET}, @code{@value{AS}} can be configured to produce either | |
24b1493d | 681 | @code{a.out} or COFF format object files. |
f009d0ab RP |
682 | @end ifset |
683 | @ifset I960 | |
684 | On the @value{TARGET}, @code{@value{AS}} can be configured to produce either | |
685 | @code{b.out} or COFF format object files. | |
686 | @end ifset | |
9dcf8057 JL |
687 | @ifset HPPA |
688 | On the @value{TARGET}, @code{@value{AS}} can be configured to produce either | |
689 | SOM or ELF format object files. | |
690 | @end ifset | |
f009d0ab | 691 | @end ifclear |
d0281557 | 692 | |
242d9c06 | 693 | @node Command Line |
b50e59fe | 694 | @section Command Line |
93b45514 | 695 | |
66b818fb | 696 | @cindex command line conventions |
f009d0ab | 697 | After the program name @code{@value{AS}}, the command line may contain |
66b818fb | 698 | options and file names. Options may appear in any order, and may be |
93b45514 RP |
699 | before, after, or between file names. The order of file names is |
700 | significant. | |
701 | ||
66b818fb RP |
702 | @cindex standard input, as input file |
703 | @kindex -- | |
47342e8f | 704 | @file{--} (two hyphens) by itself names the standard input file |
f009d0ab | 705 | explicitly, as one of the files for @code{@value{AS}} to assemble. |
47342e8f | 706 | |
66b818fb | 707 | @cindex options, command line |
93b45514 RP |
708 | Except for @samp{--} any command line argument that begins with a |
709 | hyphen (@samp{-}) is an option. Each option changes the behavior of | |
f009d0ab | 710 | @code{@value{AS}}. No option changes the way another option works. An |
47342e8f | 711 | option is a @samp{-} followed by one or more letters; the case of |
b50e59fe | 712 | the letter is important. All options are optional. |
93b45514 RP |
713 | |
714 | Some options expect exactly one file name to follow them. The file | |
715 | name may either immediately follow the option's letter (compatible | |
8babef85 | 716 | with older assemblers) or it may be the next command argument (@sc{gnu} |
93b45514 RP |
717 | standard). These two command lines are equivalent: |
718 | ||
d0281557 | 719 | @smallexample |
f009d0ab RP |
720 | @value{AS} -o my-object-file.o mumble.s |
721 | @value{AS} -omy-object-file.o mumble.s | |
d0281557 | 722 | @end smallexample |
93b45514 | 723 | |
242d9c06 | 724 | @node Input Files |
47342e8f | 725 | @section Input Files |
93b45514 | 726 | |
66b818fb RP |
727 | @cindex input |
728 | @cindex source program | |
729 | @cindex files, input | |
47342e8f | 730 | We use the phrase @dfn{source program}, abbreviated @dfn{source}, to |
f009d0ab | 731 | describe the program input to one run of @code{@value{AS}}. The program may |
93b45514 RP |
732 | be in one or more files; how the source is partitioned into files |
733 | doesn't change the meaning of the source. | |
734 | ||
b50e59fe | 735 | @c I added "con" prefix to "catenation" just to prove I can overcome my |
71dd3c40 | 736 | @c APL training... doc@cygnus.com |
b50e59fe | 737 | The source program is a concatenation of the text in all the files, in the |
47342e8f | 738 | order specified. |
93b45514 | 739 | |
f009d0ab | 740 | Each time you run @code{@value{AS}} it assembles exactly one source |
47342e8f | 741 | program. The source program is made up of one or more files. |
93b45514 RP |
742 | (The standard input is also a file.) |
743 | ||
f009d0ab | 744 | You give @code{@value{AS}} a command line that has zero or more input file |
93b45514 RP |
745 | names. The input files are read (from left file name to right). A |
746 | command line argument (in any position) that has no special meaning | |
d0281557 | 747 | is taken to be an input file name. |
93b45514 | 748 | |
f009d0ab RP |
749 | If you give @code{@value{AS}} no file names it attempts to read one input file |
750 | from the @code{@value{AS}} standard input, which is normally your terminal. You | |
751 | may have to type @key{ctl-D} to tell @code{@value{AS}} there is no more program | |
d0281557 | 752 | to assemble. |
93b45514 | 753 | |
47342e8f RP |
754 | Use @samp{--} if you need to explicitly name the standard input file |
755 | in your command line. | |
93b45514 | 756 | |
05a0e43b | 757 | If the source is empty, @code{@value{AS}} produces a small, empty object |
d0281557 | 758 | file. |
b50e59fe | 759 | |
7a4c8e5c | 760 | @subheading Filenames and Line-numbers |
66b818fb RP |
761 | |
762 | @cindex input file linenumbers | |
763 | @cindex line numbers, in input files | |
764 | There are two ways of locating a line in the input file (or files) and | |
765 | either may be used in reporting error messages. One way refers to a line | |
93b45514 | 766 | number in a physical file; the other refers to a line number in a |
66b818fb | 767 | ``logical'' file. @xref{Errors, ,Error and Warning Messages}. |
93b45514 RP |
768 | |
769 | @dfn{Physical files} are those files named in the command line given | |
f009d0ab | 770 | to @code{@value{AS}}. |
93b45514 | 771 | |
47342e8f RP |
772 | @dfn{Logical files} are simply names declared explicitly by assembler |
773 | directives; they bear no relation to physical files. Logical file names | |
f009d0ab | 774 | help error messages reflect the original source file, when @code{@value{AS}} |
7a4c8e5c | 775 | source is itself synthesized from other files. |
f009d0ab | 776 | @xref{App-File,,@code{.app-file}}. |
93b45514 | 777 | |
242d9c06 | 778 | @node Object |
93b45514 | 779 | @section Output (Object) File |
66b818fb RP |
780 | |
781 | @cindex object file | |
782 | @cindex output file | |
783 | @kindex a.out | |
784 | @kindex .o | |
f009d0ab | 785 | Every time you run @code{@value{AS}} it produces an output file, which is |
93b45514 | 786 | your assembly language program translated into numbers. This file |
65fbb2d7 RP |
787 | is the object file. Its default name is |
788 | @ifclear BOUT | |
789 | @code{a.out}. | |
790 | @end ifclear | |
f009d0ab | 791 | @ifset BOUT |
f009d0ab | 792 | @ifset GENERIC |
65fbb2d7 | 793 | @code{a.out}, or |
f009d0ab | 794 | @end ifset |
65fbb2d7 | 795 | @code{b.out} when @code{@value{AS}} is configured for the Intel 80960. |
f009d0ab | 796 | @end ifset |
65fbb2d7 RP |
797 | You can give it another name by using the @code{-o} option. Conventionally, |
798 | object file names end with @file{.o}. The default name is used for historical | |
799 | reasons: older assemblers were capable of assembling self-contained programs | |
800 | directly into a runnable program. (For some formats, this isn't currently | |
801 | possible, but it can be done for the @code{a.out} format.) | |
93b45514 | 802 | |
66b818fb RP |
803 | @cindex linker |
804 | @kindex ld | |
f009d0ab RP |
805 | The object file is meant for input to the linker @code{@value{LD}}. It contains |
806 | assembled program code, information to help @code{@value{LD}} integrate | |
b50e59fe | 807 | the assembled program into a runnable file, and (optionally) symbolic |
d0281557 | 808 | information for the debugger. |
93b45514 | 809 | |
66b818fb | 810 | @c link above to some info file(s) like the description of a.out. |
71dd3c40 | 811 | @c don't forget to describe @sc{gnu} info as well as Unix lossage. |
93b45514 | 812 | |
242d9c06 | 813 | @node Errors |
93b45514 RP |
814 | @section Error and Warning Messages |
815 | ||
66b818fb RP |
816 | @cindex error messsages |
817 | @cindex warning messages | |
3ffb03b1 | 818 | @cindex messages from assembler |
f009d0ab | 819 | @code{@value{AS}} may write warnings and error messages to the standard error |
66b818fb | 820 | file (usually your terminal). This should not happen when a compiler |
f009d0ab RP |
821 | runs @code{@value{AS}} automatically. Warnings report an assumption made so |
822 | that @code{@value{AS}} could keep assembling a flawed program; errors report a | |
b50e59fe | 823 | grave problem that stops the assembly. |
93b45514 | 824 | |
66b818fb | 825 | @cindex format of warning messages |
93b45514 | 826 | Warning messages have the format |
66b818fb | 827 | |
d0281557 | 828 | @smallexample |
b50e59fe | 829 | file_name:@b{NNN}:Warning Message Text |
d0281557 | 830 | @end smallexample |
66b818fb | 831 | |
0b5b143a | 832 | @noindent |
66b818fb | 833 | @cindex line numbers, in warnings/errors |
f009d0ab RP |
834 | (where @b{NNN} is a line number). If a logical file name has been given |
835 | (@pxref{App-File,,@code{.app-file}}) it is used for the filename, | |
836 | otherwise the name of the current input file is used. If a logical line | |
837 | number was given | |
838 | @ifset GENERIC | |
839 | (@pxref{Line,,@code{.line}}) | |
840 | @end ifset | |
841 | @ifclear GENERIC | |
842 | @ifclear A29K | |
7a4c8e5c | 843 | (@pxref{Line,,@code{.line}}) |
f009d0ab RP |
844 | @end ifclear |
845 | @ifset A29K | |
7a4c8e5c | 846 | (@pxref{Ln,,@code{.ln}}) |
f009d0ab RP |
847 | @end ifset |
848 | @end ifclear | |
63f5d795 | 849 | then it is used to calculate the number printed, |
b50e59fe RP |
850 | otherwise the actual line in the current source file is printed. The |
851 | message text is intended to be self explanatory (in the grand Unix | |
f009d0ab | 852 | tradition). |
93b45514 | 853 | |
66b818fb | 854 | @cindex format of error messages |
93b45514 | 855 | Error messages have the format |
d0281557 | 856 | @smallexample |
b50e59fe | 857 | file_name:@b{NNN}:FATAL:Error Message Text |
d0281557 | 858 | @end smallexample |
47342e8f | 859 | The file name and line number are derived as for warning |
93b45514 RP |
860 | messages. The actual message text may be rather less explanatory |
861 | because many of them aren't supposed to happen. | |
862 | ||
242d9c06 | 863 | @node Invoking |
7a4c8e5c | 864 | @chapter Command-Line Options |
66b818fb | 865 | |
3ffb03b1 | 866 | @cindex options, all versions of assembler |
66b818fb | 867 | This chapter describes command-line options available in @emph{all} |
8babef85 | 868 | versions of the @sc{gnu} assembler; @pxref{Machine Dependencies}, for options specific |
f009d0ab RP |
869 | @ifclear GENERIC |
870 | to the @value{TARGET}. | |
871 | @end ifclear | |
872 | @ifset GENERIC | |
0b5b143a | 873 | to particular machine architectures. |
f009d0ab | 874 | @end ifset |
0193302d | 875 | |
8babef85 | 876 | If you are invoking @code{@value{AS}} via the @sc{gnu} C compiler (version 2), you |
0193302d KR |
877 | can use the @samp{-Wa} option to pass arguments through to the |
878 | assembler. The assembler arguments must be separated from each other | |
879 | (and the @samp{-Wa}) by commas. For example: | |
880 | ||
881 | @smallexample | |
882 | gcc -c -g -O -Wa,-alh,-L file.c | |
883 | @end smallexample | |
884 | ||
05a0e43b RP |
885 | @noindent |
886 | emits a listing to standard output with high-level | |
0193302d KR |
887 | and assembly source. |
888 | ||
81fcb3ff RP |
889 | Usually you do not need to use this @samp{-Wa} mechanism, since many compiler |
890 | command-line options are automatically passed to the assembler by the compiler. | |
8babef85 | 891 | (You can call the @sc{gnu} compiler driver with the @samp{-v} option to see |
81fcb3ff RP |
892 | precisely what options it passes to each compilation pass, including the |
893 | assembler.) | |
d0281557 | 894 | |
f009d0ab | 895 | @menu |
35cfacf0 | 896 | * a:: -a[cdhlns] enable listings |
f009d0ab RP |
897 | * D:: -D for compatibility |
898 | * f:: -f to work faster | |
899 | * I:: -I for .include search path | |
900 | @ifclear DIFF-TBL-KLUGE | |
901 | * K:: -K for compatibility | |
902 | @end ifclear | |
903 | @ifset DIFF-TBL-KLUGE | |
904 | * K:: -K for difference tables | |
905 | @end ifset | |
906 | ||
907 | * L:: -L to retain local labels | |
79e15b8a | 908 | * M:: -M or --mri to assemble in MRI compatibility mode |
8a51eeaf | 909 | * MD:: --MD for dependency tracking |
f009d0ab RP |
910 | * o:: -o to name the object file |
911 | * R:: -R to join data and text sections | |
62e59d28 | 912 | * statistics:: --statistics to see statistics about assembly |
f009d0ab RP |
913 | * v:: -v to announce version |
914 | * W:: -W to suppress warnings | |
62e59d28 | 915 | * Z:: -Z to make object file even after errors |
f009d0ab RP |
916 | @end menu |
917 | ||
918 | @node a | |
35cfacf0 | 919 | @section Enable Listings: @code{-a[cdhlns]} |
66b818fb RP |
920 | |
921 | @kindex -a | |
35cfacf0 | 922 | @kindex -ac |
0193302d KR |
923 | @kindex -ad |
924 | @kindex -ah | |
66b818fb | 925 | @kindex -al |
0193302d | 926 | @kindex -an |
66b818fb RP |
927 | @kindex -as |
928 | @cindex listings, enabling | |
929 | @cindex assembly listings, enabling | |
0193302d KR |
930 | |
931 | These options enable listing output from the assembler. By itself, | |
932 | @samp{-a} requests high-level, assembly, and symbols listing. | |
dd565f85 | 933 | You can use other letters to select specific options for the list: |
0193302d KR |
934 | @samp{-ah} requests a high-level language listing, |
935 | @samp{-al} requests an output-program assembly listing, and | |
936 | @samp{-as} requests a symbol table listing. | |
937 | High-level listings require that a compiler debugging option like | |
938 | @samp{-g} be used, and that assembly listings (@samp{-al}) be requested | |
939 | also. | |
940 | ||
35cfacf0 ILT |
941 | Use the @samp{-ac} option to omit false conditionals from a listing. Any lines |
942 | which are not assembled because of a false @code{.if} (or @code{.ifdef}, or any | |
943 | other conditional), or a true @code{.if} followed by an @code{.else}, will be | |
944 | omitted from the listing. | |
945 | ||
dd565f85 | 946 | Use the @samp{-ad} option to omit debugging directives from the |
0193302d | 947 | listing. |
66b818fb RP |
948 | |
949 | Once you have specified one of these options, you can further control | |
950 | listing output and its appearance using the directives @code{.list}, | |
951 | @code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and | |
952 | @code{.sbttl}. | |
0193302d | 953 | The @samp{-an} option turns off all forms processing. |
66b818fb RP |
954 | If you do not request listing output with one of the @samp{-a} options, the |
955 | listing-control directives have no effect. | |
956 | ||
0193302d KR |
957 | The letters after @samp{-a} may be combined into one option, |
958 | @emph{e.g.}, @samp{-aln}. | |
959 | ||
f009d0ab | 960 | @node D |
66b818fb RP |
961 | @section @code{-D} |
962 | ||
963 | @kindex -D | |
b50e59fe | 964 | This option has no effect whatsoever, but it is accepted to make it more |
05a0e43b | 965 | likely that scripts written for other assemblers also work with |
f009d0ab | 966 | @code{@value{AS}}. |
b50e59fe | 967 | |
f009d0ab | 968 | @node f |
66b818fb RP |
969 | @section Work Faster: @code{-f} |
970 | ||
971 | @kindex -f | |
972 | @cindex trusted compiler | |
973 | @cindex faster processing (@code{-f}) | |
93b45514 | 974 | @samp{-f} should only be used when assembling programs written by a |
9dcf8057 | 975 | (trusted) compiler. @samp{-f} stops the assembler from doing whitespace |
05a0e43b RP |
976 | and comment preprocessing on |
977 | the input file(s) before assembling them. @xref{Preprocessing, | |
978 | ,Preprocessing}. | |
66b818fb | 979 | |
b50e59fe | 980 | @quotation |
05a0e43b RP |
981 | @emph{Warning:} if you use @samp{-f} when the files actually need to be |
982 | preprocessed (if they contain comments, for example), @code{@value{AS}} does | |
983 | not work correctly. | |
b50e59fe RP |
984 | @end quotation |
985 | ||
f009d0ab | 986 | @node I |
66b818fb RP |
987 | @section @code{.include} search path: @code{-I} @var{path} |
988 | ||
989 | @kindex -I @var{path} | |
990 | @cindex paths for @code{.include} | |
991 | @cindex search path for @code{.include} | |
992 | @cindex @code{include} directive search path | |
d0281557 | 993 | Use this option to add a @var{path} to the list of directories |
05a0e43b | 994 | @code{@value{AS}} searches for files specified in @code{.include} |
7a4c8e5c RP |
995 | directives (@pxref{Include,,@code{.include}}). You may use @code{-I} as |
996 | many times as necessary to include a variety of paths. The current | |
f009d0ab | 997 | working directory is always searched first; after that, @code{@value{AS}} |
7a4c8e5c RP |
998 | searches any @samp{-I} directories in the same order as they were |
999 | specified (left to right) on the command line. | |
d0281557 | 1000 | |
f009d0ab | 1001 | @node K |
80381063 | 1002 | @section Difference Tables: @code{-K} |
66b818fb | 1003 | |
80381063 | 1004 | @kindex -K |
f009d0ab RP |
1005 | @ifclear DIFF-TBL-KLUGE |
1006 | On the @value{TARGET} family, this option is allowed, but has no effect. It is | |
8babef85 | 1007 | permitted for compatibility with the @sc{gnu} assembler on other platforms, |
d0281557 | 1008 | where it can be used to warn when the assembler alters the machine code |
f009d0ab | 1009 | generated for @samp{.word} directives in difference tables. The @value{TARGET} |
b50e59fe RP |
1010 | family does not have the addressing limitations that sometimes lead to this |
1011 | alteration on other platforms. | |
f009d0ab | 1012 | @end ifclear |
b50e59fe | 1013 | |
f009d0ab | 1014 | @ifset DIFF-TBL-KLUGE |
66b818fb RP |
1015 | @cindex difference tables, warning |
1016 | @cindex warning for altered difference tables | |
f009d0ab | 1017 | @code{@value{AS}} sometimes alters the code emitted for directives of the form |
7a4c8e5c | 1018 | @samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}. |
80381063 | 1019 | You can use the @samp{-K} option if you want a warning issued when this |
d0281557 | 1020 | is done. |
f009d0ab | 1021 | @end ifset |
47342e8f | 1022 | |
f009d0ab | 1023 | @node L |
66b818fb RP |
1024 | @section Include Local Labels: @code{-L} |
1025 | ||
1026 | @kindex -L | |
1027 | @cindex local labels, retaining in output | |
b50e59fe | 1028 | Labels beginning with @samp{L} (upper case only) are called @dfn{local |
05a0e43b | 1029 | labels}. @xref{Symbol Names}. Normally you do not see such labels when |
47342e8f | 1030 | debugging, because they are intended for the use of programs (like |
b50e59fe | 1031 | compilers) that compose assembler programs, not for your notice. |
05a0e43b | 1032 | Normally both @code{@value{AS}} and @code{@value{LD}} discard such labels, so you do not |
b50e59fe | 1033 | normally debug with them. |
93b45514 | 1034 | |
f009d0ab | 1035 | This option tells @code{@value{AS}} to retain those @samp{L@dots{}} symbols |
93b45514 | 1036 | in the object file. Usually if you do this you also tell the linker |
f009d0ab | 1037 | @code{@value{LD}} to preserve symbols whose names begin with @samp{L}. |
93b45514 | 1038 | |
9dcf8057 JL |
1039 | By default, a local label is any label beginning with @samp{L}, but each |
1040 | target is allowed to redefine the local label prefix. | |
509d5555 JL |
1041 | @ifset HPPA |
1042 | On the HPPA local labels begin with @samp{L$}. | |
1043 | @end ifset | |
3ffb03b1 DE |
1044 | @ifset ARM |
1045 | @samp{;} for the ARM family; | |
99c4053d | 1046 | @end ifset |
9dcf8057 | 1047 | |
79e15b8a ILT |
1048 | @node M |
1049 | @section Assemble in MRI Compatibility Mode: @code{-M} | |
1050 | ||
1051 | @kindex -M | |
1052 | @cindex MRI compatibility mode | |
1053 | The @code{-M} or @code{--mri} option selects MRI compatibility mode. This | |
1054 | changes the syntax and pseudo-op handling of @code{@value{AS}} to make it | |
71dd3c40 ILT |
1055 | compatible with the @code{ASM68K} or the @code{ASM960} (depending upon the |
1056 | configured target) assembler from Microtec Research. The exact nature of the | |
1057 | MRI syntax will not be documented here; see the MRI manuals for more | |
7d99e8af ILT |
1058 | information. Note in particular that the handling of macros and macro |
1059 | arguments is somewhat different. The purpose of this option is to permit | |
1060 | assembling existing MRI assembler code using @code{@value{AS}}. | |
79e15b8a ILT |
1061 | |
1062 | The MRI compatibility is not complete. Certain operations of the MRI assembler | |
1063 | depend upon its object file format, and can not be supported using other object | |
1064 | file formats. Supporting these would require enhancing each object file format | |
1065 | individually. These are: | |
1066 | ||
1067 | @itemize @bullet | |
1068 | @item global symbols in common section | |
1069 | ||
71dd3c40 | 1070 | The m68k MRI assembler supports common sections which are merged by the linker. |
79e15b8a ILT |
1071 | Other object file formats do not support this. @code{@value{AS}} handles |
1072 | common sections by treating them as a single common symbol. It permits local | |
1073 | symbols to be defined within a common section, but it can not support global | |
1074 | symbols, since it has no way to describe them. | |
1075 | ||
1076 | @item complex relocations | |
1077 | ||
71dd3c40 | 1078 | The MRI assemblers support relocations against a negated section address, and |
79e15b8a ILT |
1079 | relocations which combine the start addresses of two or more sections. These |
1080 | are not support by other object file formats. | |
1081 | ||
1082 | @item @code{END} pseudo-op specifying start address | |
1083 | ||
1084 | The MRI @code{END} pseudo-op permits the specification of a start address. | |
1085 | This is not supported by other object file formats. The start address may | |
1086 | instead be specified using the @code{-e} option to the linker, or in a linker | |
1087 | script. | |
1088 | ||
71dd3c40 | 1089 | @item @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops |
79e15b8a | 1090 | |
71dd3c40 ILT |
1091 | The MRI @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops assign a module |
1092 | name to the output file. This is not supported by other object file formats. | |
79e15b8a ILT |
1093 | |
1094 | @item @code{ORG} pseudo-op | |
1095 | ||
71dd3c40 ILT |
1096 | The m68k MRI @code{ORG} pseudo-op begins an absolute section at a given |
1097 | address. This differs from the usual @code{@value{AS}} @code{.org} pseudo-op, | |
1098 | which changes the location within the current section. Absolute sections are | |
1099 | not supported by other object file formats. The address of a section may be | |
79e15b8a ILT |
1100 | assigned within a linker script. |
1101 | @end itemize | |
1102 | ||
1103 | There are some other features of the MRI assembler which are not supported by | |
1104 | @code{@value{AS}}, typically either because they are difficult or because they | |
1105 | seem of little consequence. Some of these may be supported in future releases. | |
1106 | ||
1107 | @itemize @bullet | |
1108 | ||
79e15b8a ILT |
1109 | @item EBCDIC strings |
1110 | ||
1111 | EBCDIC strings are not supported. | |
1112 | ||
1113 | @item packed binary coded decimal | |
1114 | ||
1115 | Packed binary coded decimal is not supported. This means that the @code{DC.P} | |
1116 | and @code{DCB.P} pseudo-ops are not supported. | |
1117 | ||
1118 | @item @code{FEQU} pseudo-op | |
1119 | ||
71dd3c40 | 1120 | The m68k @code{FEQU} pseudo-op is not supported. |
79e15b8a ILT |
1121 | |
1122 | @item @code{NOOBJ} pseudo-op | |
1123 | ||
71dd3c40 | 1124 | The m68k @code{NOOBJ} pseudo-op is not supported. |
79e15b8a ILT |
1125 | |
1126 | @item @code{OPT} branch control options | |
1127 | ||
71dd3c40 | 1128 | The m68k @code{OPT} branch control options---@code{B}, @code{BRS}, @code{BRB}, |
79e15b8a ILT |
1129 | @code{BRL}, and @code{BRW}---are ignored. @code{@value{AS}} automatically |
1130 | relaxes all branches, whether forward or backward, to an appropriate size, so | |
1131 | these options serve no purpose. | |
1132 | ||
1133 | @item @code{OPT} list control options | |
1134 | ||
71dd3c40 | 1135 | The following m68k @code{OPT} list control options are ignored: @code{C}, |
79e15b8a ILT |
1136 | @code{CEX}, @code{CL}, @code{CRE}, @code{E}, @code{G}, @code{I}, @code{M}, |
1137 | @code{MEX}, @code{MC}, @code{MD}, @code{X}. | |
1138 | ||
1139 | @item other @code{OPT} options | |
1140 | ||
71dd3c40 | 1141 | The following m68k @code{OPT} options are ignored: @code{NEST}, @code{O}, |
79e15b8a ILT |
1142 | @code{OLD}, @code{OP}, @code{P}, @code{PCO}, @code{PCR}, @code{PCS}, @code{R}. |
1143 | ||
1144 | @item @code{OPT} @code{D} option is default | |
1145 | ||
71dd3c40 | 1146 | The m68k @code{OPT} @code{D} option is the default, unlike the MRI assembler. |
79e15b8a ILT |
1147 | @code{OPT NOD} may be used to turn it off. |
1148 | ||
1149 | @item @code{XREF} pseudo-op. | |
1150 | ||
71dd3c40 ILT |
1151 | The m68k @code{XREF} pseudo-op is ignored. |
1152 | ||
1153 | @item @code{.debug} pseudo-op | |
1154 | ||
1155 | The i960 @code{.debug} pseudo-op is not supported. | |
1156 | ||
1157 | @item @code{.extended} pseudo-op | |
1158 | ||
1159 | The i960 @code{.extended} pseudo-op is not supported. | |
1160 | ||
1161 | @item @code{.list} pseudo-op. | |
1162 | ||
1163 | The various options of the i960 @code{.list} pseudo-op are not supported. | |
1164 | ||
1165 | @item @code{.optimize} pseudo-op | |
1166 | ||
1167 | The i960 @code{.optimize} pseudo-op is not supported. | |
1168 | ||
1169 | @item @code{.output} pseudo-op | |
1170 | ||
1171 | The i960 @code{.output} pseudo-op is not supported. | |
1172 | ||
1173 | @item @code{.setreal} pseudo-op | |
1174 | ||
1175 | The i960 @code{.setreal} pseudo-op is not supported. | |
79e15b8a | 1176 | |
79e15b8a ILT |
1177 | @end itemize |
1178 | ||
8a51eeaf TT |
1179 | @node MD |
1180 | @section Dependency tracking: @code{--MD} | |
1181 | ||
1182 | @kindex --MD | |
1183 | @cindex dependency tracking | |
1184 | @cindex make rules | |
1185 | ||
1186 | @code{@value{AS}} can generate a dependency file for the file it creates. This | |
1187 | file consists of a single rule suitable for @code{make} describing the | |
1188 | dependencies of the main source file. | |
1189 | ||
1190 | The rule is written to the file named in its argument. | |
1191 | ||
1192 | This feature is used in the automatic updating of makefiles. | |
1193 | ||
f009d0ab | 1194 | @node o |
66b818fb RP |
1195 | @section Name the Object File: @code{-o} |
1196 | ||
1197 | @kindex -o | |
1198 | @cindex naming object file | |
1199 | @cindex object file name | |
f009d0ab | 1200 | There is always one object file output when you run @code{@value{AS}}. By |
9ebc250f | 1201 | default it has the name |
f009d0ab RP |
1202 | @ifset GENERIC |
1203 | @ifset I960 | |
1204 | @file{a.out} (or @file{b.out}, for Intel 960 targets only). | |
1205 | @end ifset | |
1206 | @ifclear I960 | |
9ebc250f | 1207 | @file{a.out}. |
f009d0ab RP |
1208 | @end ifclear |
1209 | @end ifset | |
1210 | @ifclear GENERIC | |
1211 | @ifset I960 | |
9ebc250f | 1212 | @file{b.out}. |
f009d0ab RP |
1213 | @end ifset |
1214 | @ifclear I960 | |
9ebc250f | 1215 | @file{a.out}. |
f009d0ab RP |
1216 | @end ifclear |
1217 | @end ifclear | |
1218 | You use this option (which takes exactly one filename) to give the | |
1219 | object file a different name. | |
93b45514 | 1220 | |
05a0e43b | 1221 | Whatever the object file is called, @code{@value{AS}} overwrites any |
93b45514 RP |
1222 | existing file of the same name. |
1223 | ||
f009d0ab | 1224 | @node R |
66b818fb RP |
1225 | @section Join Data and Text Sections: @code{-R} |
1226 | ||
1227 | @kindex -R | |
1228 | @cindex data and text sections, joining | |
1229 | @cindex text and data sections, joining | |
1230 | @cindex joining text and data sections | |
1231 | @cindex merging text and data sections | |
f009d0ab | 1232 | @code{-R} tells @code{@value{AS}} to write the object file as if all |
24b1493d | 1233 | data-section data lives in the text section. This is only done at |
93b45514 | 1234 | the very last moment: your binary data are the same, but data |
24b1493d | 1235 | section parts are relocated differently. The data section part of |
9ebc250f | 1236 | your object file is zero bytes long because all its bytes are |
24b1493d | 1237 | appended to the text section. (@xref{Sections,,Sections and Relocation}.) |
93b45514 | 1238 | |
b50e59fe | 1239 | When you specify @code{-R} it would be possible to generate shorter |
05a0e43b | 1240 | address displacements (because we do not have to cross between text and |
24b1493d | 1241 | data section). We refrain from doing this simply for compatibility with |
f009d0ab | 1242 | older versions of @code{@value{AS}}. In future, @code{-R} may work this way. |
93b45514 | 1243 | |
f009d0ab RP |
1244 | @ifset COFF |
1245 | When @code{@value{AS}} is configured for COFF output, | |
66b818fb | 1246 | this option is only useful if you use sections named @samp{.text} and |
f009d0ab RP |
1247 | @samp{.data}. |
1248 | @end ifset | |
66b818fb | 1249 | |
9dcf8057 | 1250 | @ifset HPPA |
05a0e43b RP |
1251 | @code{-R} is not supported for any of the HPPA targets. Using |
1252 | @code{-R} generates a warning from @code{@value{AS}}. | |
9dcf8057 JL |
1253 | @end ifset |
1254 | ||
62e59d28 | 1255 | @node statistics |
81fcb3ff | 1256 | @section Display Assembly Statistics: @code{--statistics} |
62e59d28 RP |
1257 | |
1258 | @kindex --statistics | |
1259 | @cindex statistics, about assembly | |
1260 | @cindex time, total for assembly | |
1261 | @cindex space used, maximum for assembly | |
1262 | Use @samp{--statistics} to display two statistics about the resources used by | |
1263 | @code{@value{AS}}: the maximum amount of space allocated during the assembly | |
1264 | (in bytes), and the total execution time taken for the assembly (in @sc{cpu} | |
1265 | seconds). | |
1266 | ||
f009d0ab | 1267 | @node v |
66b818fb RP |
1268 | @section Announce Version: @code{-v} |
1269 | ||
1270 | @kindex -v | |
1271 | @kindex -version | |
3ffb03b1 DE |
1272 | @cindex assembler version |
1273 | @cindex version of assembler | |
7d7ecbdd RP |
1274 | You can find out what version of as is running by including the |
1275 | option @samp{-v} (which you can also spell as @samp{-version}) on the | |
1276 | command line. | |
1277 | ||
f009d0ab | 1278 | @node W |
66b818fb RP |
1279 | @section Suppress Warnings: @code{-W} |
1280 | ||
1281 | @kindex -W | |
1282 | @cindex suppressing warnings | |
1283 | @cindex warnings, suppressing | |
f009d0ab | 1284 | @code{@value{AS}} should never give a warning or error message when |
93b45514 | 1285 | assembling compiler output. But programs written by people often |
f009d0ab | 1286 | cause @code{@value{AS}} to give a warning that a particular assumption was |
93b45514 | 1287 | made. All such warnings are directed to the standard error file. |
47342e8f RP |
1288 | If you use this option, no warnings are issued. This option only |
1289 | affects the warning messages: it does not change any particular of how | |
f009d0ab | 1290 | @code{@value{AS}} assembles your file. Errors, which stop the assembly, are |
93b45514 RP |
1291 | still reported. |
1292 | ||
62e59d28 RP |
1293 | @node Z |
1294 | @section Generate Object File in Spite of Errors: @code{-Z} | |
1295 | @cindex object file, after errors | |
1296 | @cindex errors, continuing after | |
1297 | After an error message, @code{@value{AS}} normally produces no output. If for | |
1298 | some reason you are interested in object file output even after | |
1299 | @code{@value{AS}} gives an error message on your program, use the @samp{-Z} | |
1300 | option. If there are any errors, @code{@value{AS}} continues anyways, and | |
1301 | writes an object file after a final warning message of the form @samp{@var{n} | |
1302 | errors, @var{m} warnings, generating bad object file.} | |
1303 | ||
242d9c06 | 1304 | @node Syntax |
d0281557 | 1305 | @chapter Syntax |
66b818fb RP |
1306 | |
1307 | @cindex machine-independent syntax | |
1308 | @cindex syntax, machine-independent | |
47342e8f | 1309 | This chapter describes the machine-independent syntax allowed in a |
f009d0ab RP |
1310 | source file. @code{@value{AS}} syntax is similar to what many other |
1311 | assemblers use; it is inspired by the BSD 4.2 | |
1312 | @ifclear VAX | |
1313 | assembler. | |
1314 | @end ifclear | |
1315 | @ifset VAX | |
1316 | assembler, except that @code{@value{AS}} does not assemble Vax bit-fields. | |
1317 | @end ifset | |
b50e59fe | 1318 | |
7a4c8e5c | 1319 | @menu |
05a0e43b | 1320 | * Preprocessing:: Preprocessing |
ba487f3a RP |
1321 | * Whitespace:: Whitespace |
1322 | * Comments:: Comments | |
1323 | * Symbol Intro:: Symbols | |
1324 | * Statements:: Statements | |
1325 | * Constants:: Constants | |
7a4c8e5c RP |
1326 | @end menu |
1327 | ||
05a0e43b RP |
1328 | @node Preprocessing |
1329 | @section Preprocessing | |
93b45514 | 1330 | |
66b818fb | 1331 | @cindex preprocessing |
05a0e43b | 1332 | The @code{@value{AS}} internal preprocessor: |
b50e59fe | 1333 | @itemize @bullet |
66b818fb | 1334 | @cindex whitespace, removed by preprocessor |
b50e59fe RP |
1335 | @item |
1336 | adjusts and removes extra whitespace. It leaves one space or tab before | |
1337 | the keywords on a line, and turns any other whitespace on the line into | |
1338 | a single space. | |
93b45514 | 1339 | |
66b818fb | 1340 | @cindex comments, removed by preprocessor |
b50e59fe RP |
1341 | @item |
1342 | removes all comments, replacing them with a single space, or an | |
1343 | appropriate number of newlines. | |
93b45514 | 1344 | |
66b818fb | 1345 | @cindex constants, converted by preprocessor |
b50e59fe RP |
1346 | @item |
1347 | converts character constants into the appropriate numeric values. | |
1348 | @end itemize | |
1349 | ||
dd565f85 | 1350 | It does not do macro processing, include file handling, or |
05a0e43b | 1351 | anything else you may get from your C compiler's preprocessor. You can |
9dcf8057 | 1352 | do include file processing with the @code{.include} directive |
dd565f85 RP |
1353 | (@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver |
1354 | to get other ``CPP'' style preprocessing, by giving the input file a | |
1355 | @samp{.S} suffix. @xref{Overall Options,, Options Controlling the Kind of | |
1356 | Output, gcc.info, Using GNU CC}. | |
9dcf8057 | 1357 | |
b50e59fe | 1358 | Excess whitespace, comments, and character constants |
93b45514 | 1359 | cannot be used in the portions of the input text that are not |
05a0e43b | 1360 | preprocessed. |
93b45514 | 1361 | |
66b818fb RP |
1362 | @cindex turning preprocessing on and off |
1363 | @cindex preprocessing, turning on and off | |
1364 | @kindex #NO_APP | |
1365 | @kindex #APP | |
05a0e43b RP |
1366 | If the first line of an input file is @code{#NO_APP} or if you use the |
1367 | @samp{-f} option, whitespace and comments are not removed from the input file. | |
1368 | Within an input file, you can ask for whitespace and comment removal in | |
1369 | specific portions of the by putting a line that says @code{#APP} before the | |
1370 | text that may contain whitespace or comments, and putting a line that says | |
1371 | @code{#NO_APP} after this text. This feature is mainly intend to support | |
1372 | @code{asm} statements in compilers whose output is otherwise free of comments | |
1373 | and whitespace. | |
93b45514 | 1374 | |
242d9c06 | 1375 | @node Whitespace |
93b45514 | 1376 | @section Whitespace |
66b818fb RP |
1377 | |
1378 | @cindex whitespace | |
93b45514 | 1379 | @dfn{Whitespace} is one or more blanks or tabs, in any order. |
7a4c8e5c RP |
1380 | Whitespace is used to separate symbols, and to make programs neater for |
1381 | people to read. Unless within character constants | |
1382 | (@pxref{Characters,,Character Constants}), any whitespace means the same | |
1383 | as exactly one space. | |
93b45514 | 1384 | |
242d9c06 | 1385 | @node Comments |
93b45514 | 1386 | @section Comments |
66b818fb RP |
1387 | |
1388 | @cindex comments | |
f009d0ab | 1389 | There are two ways of rendering comments to @code{@value{AS}}. In both |
93b45514 RP |
1390 | cases the comment is equivalent to one space. |
1391 | ||
d0281557 RP |
1392 | Anything from @samp{/*} through the next @samp{*/} is a comment. |
1393 | This means you may not nest these comments. | |
93b45514 | 1394 | |
d0281557 | 1395 | @smallexample |
93b45514 RP |
1396 | /* |
1397 | The only way to include a newline ('\n') in a comment | |
1398 | is to use this sort of comment. | |
1399 | */ | |
47342e8f | 1400 | |
93b45514 | 1401 | /* This sort of comment does not nest. */ |
d0281557 | 1402 | @end smallexample |
93b45514 | 1403 | |
66b818fb | 1404 | @cindex line comment character |
93b45514 | 1405 | Anything from the @dfn{line comment} character to the next newline |
47342e8f | 1406 | is considered a comment and is ignored. The line comment character is |
910d7df2 C |
1407 | @ifset A29K |
1408 | @samp{;} for the AMD 29K family; | |
1409 | @end ifset | |
99c4053d KR |
1410 | @ifset ARC |
1411 | @samp{;} on the ARC; | |
1412 | @end ifset | |
f009d0ab | 1413 | @ifset H8/300 |
9ebc250f | 1414 | @samp{;} for the H8/300 family; |
f009d0ab RP |
1415 | @end ifset |
1416 | @ifset H8/500 | |
1417 | @samp{!} for the H8/500 family; | |
1418 | @end ifset | |
9dcf8057 JL |
1419 | @ifset HPPA |
1420 | @samp{;} for the HPPA; | |
1421 | @end ifset | |
910d7df2 C |
1422 | @ifset I960 |
1423 | @samp{#} on the i960; | |
1424 | @end ifset | |
f009d0ab RP |
1425 | @ifset SH |
1426 | @samp{!} for the Hitachi SH; | |
1427 | @end ifset | |
910d7df2 C |
1428 | @ifset SPARC |
1429 | @samp{!} on the SPARC; | |
1430 | @end ifset | |
1431 | @ifset M680X0 | |
1432 | @samp{|} on the 680x0; | |
1433 | @end ifset | |
1434 | @ifset VAX | |
1435 | @samp{#} on the Vax; | |
1436 | @end ifset | |
f009d0ab | 1437 | @ifset Z8000 |
ba487f3a | 1438 | @samp{!} for the Z8000; |
f009d0ab RP |
1439 | @end ifset |
1440 | see @ref{Machine Dependencies}. @refill | |
9ebc250f | 1441 | @c FIXME What about i386, m88k, i860? |
09352a5d | 1442 | |
f009d0ab | 1443 | @ifset GENERIC |
b50e59fe | 1444 | On some machines there are two different line comment characters. One |
05a0e43b RP |
1445 | character only begins a comment if it is the first non-whitespace character on |
1446 | a line, while the other always begins a comment. | |
f009d0ab | 1447 | @end ifset |
93b45514 | 1448 | |
66b818fb RP |
1449 | @kindex # |
1450 | @cindex lines starting with @code{#} | |
1451 | @cindex logical line numbers | |
dd565f85 RP |
1452 | To be compatible with past assemblers, lines that begin with @samp{#} have a |
1453 | special interpretation. Following the @samp{#} should be an absolute | |
05a0e43b | 1454 | expression (@pxref{Expressions}): the logical line number of the @emph{next} |
dd565f85 RP |
1455 | line. Then a string (@pxref{Strings,, Strings}) is allowed: if present it is a |
1456 | new logical file name. The rest of the line, if any, should be whitespace. | |
93b45514 RP |
1457 | |
1458 | If the first non-whitespace characters on the line are not numeric, | |
1459 | the line is ignored. (Just like a comment.) | |
dd565f85 | 1460 | |
d0281557 | 1461 | @smallexample |
93b45514 RP |
1462 | # This is an ordinary comment. |
1463 | # 42-6 "new_file_name" # New logical file name | |
1464 | # This is logical line # 36. | |
d0281557 | 1465 | @end smallexample |
93b45514 | 1466 | This feature is deprecated, and may disappear from future versions |
f009d0ab | 1467 | of @code{@value{AS}}. |
93b45514 | 1468 | |
242d9c06 | 1469 | @node Symbol Intro |
93b45514 | 1470 | @section Symbols |
66b818fb | 1471 | |
66b818fb | 1472 | @cindex characters used in symbols |
f009d0ab RP |
1473 | @ifclear SPECIAL-SYMS |
1474 | A @dfn{symbol} is one or more characters chosen from the set of all | |
1475 | letters (both upper and lower case), digits and the three characters | |
1476 | @samp{_.$}. | |
1477 | @end ifclear | |
1478 | @ifset SPECIAL-SYMS | |
1479 | @ifclear GENERIC | |
1480 | @ifset H8 | |
93b45514 | 1481 | A @dfn{symbol} is one or more characters chosen from the set of all |
f009d0ab RP |
1482 | letters (both upper and lower case), digits and the three characters |
1483 | @samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in | |
1484 | symbol names.) | |
1485 | @end ifset | |
1486 | @end ifclear | |
1487 | @end ifset | |
1488 | @ifset GENERIC | |
24b1493d | 1489 | On most machines, you can also use @code{$} in symbol names; exceptions |
f009d0ab RP |
1490 | are noted in @ref{Machine Dependencies}. |
1491 | @end ifset | |
24b1493d | 1492 | No symbol may begin with a digit. Case is significant. |
b50e59fe RP |
1493 | There is no length limit: all characters are significant. Symbols are |
1494 | delimited by characters not in that set, or by the beginning of a file | |
1495 | (since the source program must end with a newline, the end of a file is | |
1496 | not a possible symbol delimiter). @xref{Symbols}. | |
66b818fb | 1497 | @cindex length of symbols |
93b45514 | 1498 | |
242d9c06 | 1499 | @node Statements |
93b45514 | 1500 | @section Statements |
66b818fb RP |
1501 | |
1502 | @cindex statements, structure of | |
1503 | @cindex line separator character | |
1504 | @cindex statement separator character | |
f009d0ab RP |
1505 | @ifclear GENERIC |
1506 | @ifclear abnormal-separator | |
d0281557 RP |
1507 | A @dfn{statement} ends at a newline character (@samp{\n}) or at a |
1508 | semicolon (@samp{;}). The newline or semicolon is considered part of | |
1509 | the preceding statement. Newlines and semicolons within character | |
05a0e43b | 1510 | constants are an exception: they do not end statements. |
f009d0ab RP |
1511 | @end ifclear |
1512 | @ifset abnormal-separator | |
1513 | @ifset A29K | |
d0281557 RP |
1514 | A @dfn{statement} ends at a newline character (@samp{\n}) or an ``at'' |
1515 | sign (@samp{@@}). The newline or at sign is considered part of the | |
1516 | preceding statement. Newlines and at signs within character constants | |
05a0e43b | 1517 | are an exception: they do not end statements. |
f009d0ab | 1518 | @end ifset |
9dcf8057 JL |
1519 | @ifset HPPA |
1520 | A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation | |
1521 | point (@samp{!}). The newline or exclamation point is considered part of the | |
1522 | preceding statement. Newlines and exclamation points within character | |
05a0e43b | 1523 | constants are an exception: they do not end statements. |
9dcf8057 | 1524 | @end ifset |
f009d0ab RP |
1525 | @ifset H8 |
1526 | A @dfn{statement} ends at a newline character (@samp{\n}); or (for the | |
1527 | H8/300) a dollar sign (@samp{$}); or (for the | |
f009d0ab | 1528 | Hitachi-SH or the |
f009d0ab RP |
1529 | H8/500) a semicolon |
1530 | (@samp{;}). The newline or separator character is considered part of | |
1531 | the preceding statement. Newlines and separators within character | |
05a0e43b | 1532 | constants are an exception: they do not end statements. |
f009d0ab RP |
1533 | @end ifset |
1534 | @end ifset | |
1535 | @end ifclear | |
1536 | @ifset GENERIC | |
24b1493d RP |
1537 | A @dfn{statement} ends at a newline character (@samp{\n}) or line |
1538 | separator character. (The line separator is usually @samp{;}, unless | |
f009d0ab | 1539 | this conflicts with the comment character; @pxref{Machine Dependencies}.) The |
24b1493d RP |
1540 | newline or separator character is considered part of the preceding |
1541 | statement. Newlines and separators within character constants are an | |
05a0e43b | 1542 | exception: they do not end statements. |
f009d0ab | 1543 | @end ifset |
d0281557 | 1544 | |
66b818fb RP |
1545 | @cindex newline, required at file end |
1546 | @cindex EOF, newline must precede | |
93b45514 | 1547 | It is an error to end any statement with end-of-file: the last |
b50e59fe | 1548 | character of any input file should be a newline.@refill |
93b45514 | 1549 | |
66b818fb RP |
1550 | @cindex continuing statements |
1551 | @cindex multi-line statements | |
1552 | @cindex statement on multiple lines | |
93b45514 RP |
1553 | You may write a statement on more than one line if you put a |
1554 | backslash (@kbd{\}) immediately in front of any newlines within the | |
f009d0ab | 1555 | statement. When @code{@value{AS}} reads a backslashed newline both |
93b45514 RP |
1556 | characters are ignored. You can even put backslashed newlines in |
1557 | the middle of symbol names without changing the meaning of your | |
1558 | source program. | |
1559 | ||
47342e8f | 1560 | An empty statement is allowed, and may include whitespace. It is ignored. |
93b45514 | 1561 | |
66b818fb RP |
1562 | @cindex instructions and directives |
1563 | @cindex directives and instructions | |
b50e59fe | 1564 | @c "key symbol" is not used elsewhere in the document; seems pedantic to |
71dd3c40 | 1565 | @c @defn{} it in that case, as was done previously... doc@cygnus.com, |
d0281557 | 1566 | @c 13feb91. |
47342e8f | 1567 | A statement begins with zero or more labels, optionally followed by a |
b50e59fe | 1568 | key symbol which determines what kind of statement it is. The key |
93b45514 | 1569 | symbol determines the syntax of the rest of the statement. If the |
b50e59fe | 1570 | symbol begins with a dot @samp{.} then the statement is an assembler |
47342e8f RP |
1571 | directive: typically valid for any computer. If the symbol begins with |
1572 | a letter the statement is an assembly language @dfn{instruction}: it | |
05a0e43b | 1573 | assembles into a machine language instruction. |
f009d0ab | 1574 | @ifset GENERIC |
05a0e43b | 1575 | Different versions of @code{@value{AS}} for different computers |
d0281557 RP |
1576 | recognize different instructions. In fact, the same symbol may |
1577 | represent a different instruction in a different computer's assembly | |
1578 | language.@refill | |
f009d0ab | 1579 | @end ifset |
47342e8f | 1580 | |
66b818fb RP |
1581 | @cindex @code{:} (label) |
1582 | @cindex label (@code{:}) | |
d0281557 | 1583 | A label is a symbol immediately followed by a colon (@code{:}). |
47342e8f | 1584 | Whitespace before a label or after a colon is permitted, but you may not |
d0281557 | 1585 | have whitespace between a label's symbol and its colon. @xref{Labels}. |
93b45514 | 1586 | |
9dcf8057 JL |
1587 | @ifset HPPA |
1588 | For HPPA targets, labels need not be immediately followed by a colon, but | |
1589 | the definition of a label must begin in column zero. This also implies that | |
1590 | only one label may be defined on each line. | |
1591 | @end ifset | |
1592 | ||
d0281557 | 1593 | @smallexample |
93b45514 | 1594 | label: .directive followed by something |
24b1493d | 1595 | another_label: # This is an empty statement. |
93b45514 | 1596 | instruction operand_1, operand_2, @dots{} |
d0281557 | 1597 | @end smallexample |
93b45514 | 1598 | |
242d9c06 | 1599 | @node Constants |
93b45514 | 1600 | @section Constants |
66b818fb RP |
1601 | |
1602 | @cindex constants | |
93b45514 RP |
1603 | A constant is a number, written so that its value is known by |
1604 | inspection, without knowing any context. Like this: | |
f4335d56 | 1605 | @smallexample |
f009d0ab | 1606 | @group |
93b45514 RP |
1607 | .byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value. |
1608 | .ascii "Ring the bell\7" # A string constant. | |
1609 | .octa 0x123456789abcdef0123456789ABCDEF0 # A bignum. | |
1610 | .float 0f-314159265358979323846264338327\ | |
1611 | 95028841971.693993751E-40 # - pi, a flonum. | |
f009d0ab | 1612 | @end group |
f4335d56 | 1613 | @end smallexample |
93b45514 | 1614 | |
7a4c8e5c | 1615 | @menu |
ba487f3a RP |
1616 | * Characters:: Character Constants |
1617 | * Numbers:: Number Constants | |
7a4c8e5c RP |
1618 | @end menu |
1619 | ||
242d9c06 | 1620 | @node Characters |
93b45514 | 1621 | @subsection Character Constants |
66b818fb RP |
1622 | |
1623 | @cindex character constants | |
1624 | @cindex constants, character | |
47342e8f RP |
1625 | There are two kinds of character constants. A @dfn{character} stands |
1626 | for one character in one byte and its value may be used in | |
93b45514 | 1627 | numeric expressions. String constants (properly called string |
47342e8f | 1628 | @emph{literals}) are potentially many bytes and their values may not be |
93b45514 RP |
1629 | used in arithmetic expressions. |
1630 | ||
7a4c8e5c | 1631 | @menu |
ba487f3a RP |
1632 | * Strings:: Strings |
1633 | * Chars:: Characters | |
7a4c8e5c RP |
1634 | @end menu |
1635 | ||
242d9c06 | 1636 | @node Strings |
93b45514 | 1637 | @subsubsection Strings |
66b818fb RP |
1638 | |
1639 | @cindex string constants | |
1640 | @cindex constants, string | |
93b45514 | 1641 | A @dfn{string} is written between double-quotes. It may contain |
47342e8f | 1642 | double-quotes or null characters. The way to get special characters |
93b45514 | 1643 | into a string is to @dfn{escape} these characters: precede them with |
b50e59fe | 1644 | a backslash @samp{\} character. For example @samp{\\} represents |
93b45514 | 1645 | one backslash: the first @code{\} is an escape which tells |
f009d0ab RP |
1646 | @code{@value{AS}} to interpret the second character literally as a backslash |
1647 | (which prevents @code{@value{AS}} from recognizing the second @code{\} as an | |
93b45514 RP |
1648 | escape character). The complete list of escapes follows. |
1649 | ||
66b818fb RP |
1650 | @cindex escape codes, character |
1651 | @cindex character escape codes | |
93b45514 | 1652 | @table @kbd |
ba487f3a RP |
1653 | @c @item \a |
1654 | @c Mnemonic for ACKnowledge; for ASCII this is octal code 007. | |
66b818fb | 1655 | @c |
66b818fb RP |
1656 | @cindex @code{\b} (backspace character) |
1657 | @cindex backspace (@code{\b}) | |
71dd3c40 | 1658 | @item \b |
93b45514 | 1659 | Mnemonic for backspace; for ASCII this is octal code 010. |
66b818fb | 1660 | |
ba487f3a RP |
1661 | @c @item \e |
1662 | @c Mnemonic for EOText; for ASCII this is octal code 004. | |
66b818fb | 1663 | @c |
66b818fb RP |
1664 | @cindex @code{\f} (formfeed character) |
1665 | @cindex formfeed (@code{\f}) | |
71dd3c40 | 1666 | @item \f |
93b45514 | 1667 | Mnemonic for FormFeed; for ASCII this is octal code 014. |
66b818fb | 1668 | |
66b818fb RP |
1669 | @cindex @code{\n} (newline character) |
1670 | @cindex newline (@code{\n}) | |
71dd3c40 | 1671 | @item \n |
93b45514 | 1672 | Mnemonic for newline; for ASCII this is octal code 012. |
66b818fb | 1673 | |
ba487f3a RP |
1674 | @c @item \p |
1675 | @c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}. | |
66b818fb | 1676 | @c |
66b818fb RP |
1677 | @cindex @code{\r} (carriage return character) |
1678 | @cindex carriage return (@code{\r}) | |
71dd3c40 | 1679 | @item \r |
93b45514 | 1680 | Mnemonic for carriage-Return; for ASCII this is octal code 015. |
66b818fb | 1681 | |
ba487f3a RP |
1682 | @c @item \s |
1683 | @c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with | |
1684 | @c other assemblers. | |
66b818fb | 1685 | @c |
66b818fb RP |
1686 | @cindex @code{\t} (tab) |
1687 | @cindex tab (@code{\t}) | |
71dd3c40 | 1688 | @item \t |
93b45514 | 1689 | Mnemonic for horizontal Tab; for ASCII this is octal code 011. |
66b818fb | 1690 | |
ba487f3a RP |
1691 | @c @item \v |
1692 | @c Mnemonic for Vertical tab; for ASCII this is octal code 013. | |
1693 | @c @item \x @var{digit} @var{digit} @var{digit} | |
1694 | @c A hexadecimal character code. The numeric code is 3 hexadecimal digits. | |
66b818fb | 1695 | @c |
66b818fb RP |
1696 | @cindex @code{\@var{ddd}} (octal character code) |
1697 | @cindex octal character code (@code{\@var{ddd}}) | |
71dd3c40 | 1698 | @item \ @var{digit} @var{digit} @var{digit} |
93b45514 | 1699 | An octal character code. The numeric code is 3 octal digits. |
47342e8f RP |
1700 | For compatibility with other Unix systems, 8 and 9 are accepted as digits: |
1701 | for example, @code{\008} has the value 010, and @code{\009} the value 011. | |
66b818fb | 1702 | |
910d7df2 C |
1703 | @cindex @code{\@var{xd...}} (hex character code) |
1704 | @cindex hex character code (@code{\@var{xd...}}) | |
1705 | @item \@code{x} @var{hex-digits...} | |
1706 | A hex character code. All trailing hex digits are combined. Either upper or | |
1707 | lower case @code{x} works. | |
9dcf8057 | 1708 | |
66b818fb RP |
1709 | @cindex @code{\\} (@samp{\} character) |
1710 | @cindex backslash (@code{\\}) | |
71dd3c40 | 1711 | @item \\ |
93b45514 | 1712 | Represents one @samp{\} character. |
66b818fb | 1713 | |
ba487f3a RP |
1714 | @c @item \' |
1715 | @c Represents one @samp{'} (accent acute) character. | |
1716 | @c This is needed in single character literals | |
7a4c8e5c | 1717 | @c (@xref{Characters,,Character Constants}.) to represent |
ba487f3a | 1718 | @c a @samp{'}. |
66b818fb | 1719 | @c |
66b818fb RP |
1720 | @cindex @code{\"} (doublequote character) |
1721 | @cindex doublequote (@code{\"}) | |
71dd3c40 | 1722 | @item \" |
93b45514 RP |
1723 | Represents one @samp{"} character. Needed in strings to represent |
1724 | this character, because an unescaped @samp{"} would end the string. | |
66b818fb | 1725 | |
93b45514 | 1726 | @item \ @var{anything-else} |
05a0e43b | 1727 | Any other character when escaped by @kbd{\} gives a warning, but |
dd565f85 | 1728 | assembles as if the @samp{\} was not present. The idea is that if |
93b45514 | 1729 | you used an escape sequence you clearly didn't want the literal |
f009d0ab RP |
1730 | interpretation of the following character. However @code{@value{AS}} has no |
1731 | other interpretation, so @code{@value{AS}} knows it is giving you the wrong | |
93b45514 RP |
1732 | code and warns you of the fact. |
1733 | @end table | |
1734 | ||
1735 | Which characters are escapable, and what those escapes represent, | |
1736 | varies widely among assemblers. The current set is what we think | |
d0281557 | 1737 | the BSD 4.2 assembler recognizes, and is a subset of what most C |
05a0e43b | 1738 | compilers recognize. If you are in doubt, do not use an escape |
93b45514 RP |
1739 | sequence. |
1740 | ||
242d9c06 | 1741 | @node Chars |
93b45514 | 1742 | @subsubsection Characters |
66b818fb RP |
1743 | |
1744 | @cindex single character constant | |
1745 | @cindex character, single | |
1746 | @cindex constant, single character | |
93b45514 RP |
1747 | A single character may be written as a single quote immediately |
1748 | followed by that character. The same escapes apply to characters as | |
1749 | to strings. So if you want to write the character backslash, you | |
1750 | must write @kbd{'\\} where the first @code{\} escapes the second | |
b50e59fe | 1751 | @code{\}. As you can see, the quote is an acute accent, not a |
d0281557 | 1752 | grave accent. A newline |
f009d0ab RP |
1753 | @ifclear GENERIC |
1754 | @ifclear abnormal-separator | |
09352a5d | 1755 | (or semicolon @samp{;}) |
f009d0ab RP |
1756 | @end ifclear |
1757 | @ifset abnormal-separator | |
1758 | @ifset A29K | |
b50e59fe | 1759 | (or at sign @samp{@@}) |
f009d0ab RP |
1760 | @end ifset |
1761 | @ifset H8 | |
1762 | (or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the | |
f009d0ab | 1763 | Hitachi SH or |
f009d0ab RP |
1764 | H8/500) |
1765 | @end ifset | |
1766 | @end ifset | |
1767 | @end ifclear | |
d0281557 RP |
1768 | immediately following an acute accent is taken as a literal character |
1769 | and does not count as the end of a statement. The value of a character | |
93b45514 | 1770 | constant in a numeric expression is the machine's byte-wide code for |
f009d0ab | 1771 | that character. @code{@value{AS}} assumes your character code is ASCII: |
d0281557 | 1772 | @kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill |
93b45514 | 1773 | |
242d9c06 | 1774 | @node Numbers |
93b45514 | 1775 | @subsection Number Constants |
66b818fb RP |
1776 | |
1777 | @cindex constants, number | |
1778 | @cindex number constants | |
f009d0ab | 1779 | @code{@value{AS}} distinguishes three kinds of numbers according to how they |
47342e8f RP |
1780 | are stored in the target machine. @emph{Integers} are numbers that |
1781 | would fit into an @code{int} in the C language. @emph{Bignums} are | |
d0281557 | 1782 | integers, but they are stored in more than 32 bits. @emph{Flonums} |
93b45514 RP |
1783 | are floating point numbers, described below. |
1784 | ||
7a4c8e5c | 1785 | @menu |
ba487f3a RP |
1786 | * Integers:: Integers |
1787 | * Bignums:: Bignums | |
1788 | * Flonums:: Flonums | |
f009d0ab RP |
1789 | @ifclear GENERIC |
1790 | @ifset I960 | |
ba487f3a | 1791 | * Bit Fields:: Bit Fields |
f009d0ab RP |
1792 | @end ifset |
1793 | @end ifclear | |
7a4c8e5c RP |
1794 | @end menu |
1795 | ||
242d9c06 | 1796 | @node Integers |
93b45514 | 1797 | @subsubsection Integers |
66b818fb RP |
1798 | @cindex integers |
1799 | @cindex constants, integer | |
1800 | ||
1801 | @cindex binary integers | |
1802 | @cindex integers, binary | |
b50e59fe RP |
1803 | A binary integer is @samp{0b} or @samp{0B} followed by zero or more of |
1804 | the binary digits @samp{01}. | |
1805 | ||
66b818fb RP |
1806 | @cindex octal integers |
1807 | @cindex integers, octal | |
93b45514 RP |
1808 | An octal integer is @samp{0} followed by zero or more of the octal |
1809 | digits (@samp{01234567}). | |
1810 | ||
66b818fb RP |
1811 | @cindex decimal integers |
1812 | @cindex integers, decimal | |
93b45514 RP |
1813 | A decimal integer starts with a non-zero digit followed by zero or |
1814 | more digits (@samp{0123456789}). | |
1815 | ||
66b818fb RP |
1816 | @cindex hexadecimal integers |
1817 | @cindex integers, hexadecimal | |
93b45514 RP |
1818 | A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or |
1819 | more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}. | |
1820 | ||
47342e8f | 1821 | Integers have the usual values. To denote a negative integer, use |
b50e59fe | 1822 | the prefix operator @samp{-} discussed under expressions |
7a4c8e5c | 1823 | (@pxref{Prefix Ops,,Prefix Operators}). |
93b45514 | 1824 | |
242d9c06 | 1825 | @node Bignums |
93b45514 | 1826 | @subsubsection Bignums |
66b818fb RP |
1827 | |
1828 | @cindex bignums | |
1829 | @cindex constants, bignum | |
93b45514 RP |
1830 | A @dfn{bignum} has the same syntax and semantics as an integer |
1831 | except that the number (or its negative) takes more than 32 bits to | |
1832 | represent in binary. The distinction is made because in some places | |
1833 | integers are permitted while bignums are not. | |
1834 | ||
242d9c06 | 1835 | @node Flonums |
93b45514 | 1836 | @subsubsection Flonums |
66b818fb RP |
1837 | @cindex flonums |
1838 | @cindex floating point numbers | |
1839 | @cindex constants, floating point | |
1840 | ||
1841 | @cindex precision, floating point | |
b50e59fe | 1842 | A @dfn{flonum} represents a floating point number. The translation is |
66b818fb | 1843 | indirect: a decimal floating point number from the text is converted by |
f009d0ab | 1844 | @code{@value{AS}} to a generic binary floating point number of more than |
b50e59fe RP |
1845 | sufficient precision. This generic floating point number is converted |
1846 | to a particular computer's floating point format (or formats) by a | |
f009d0ab | 1847 | portion of @code{@value{AS}} specialized to that computer. |
93b45514 RP |
1848 | |
1849 | A flonum is written by writing (in order) | |
1850 | @itemize @bullet | |
1851 | @item | |
1852 | The digit @samp{0}. | |
9dcf8057 | 1853 | @ifset HPPA |
05a0e43b | 1854 | (@samp{0} is optional on the HPPA.) |
9dcf8057 | 1855 | @end ifset |
f009d0ab | 1856 | |
93b45514 | 1857 | @item |
f009d0ab RP |
1858 | A letter, to tell @code{@value{AS}} the rest of the number is a flonum. |
1859 | @ifset GENERIC | |
66b818fb | 1860 | @kbd{e} is recommended. Case is not important. |
0b5b143a RP |
1861 | @ignore |
1862 | @c FIXME: verify if flonum syntax really this vague for most cases | |
05a0e43b RP |
1863 | (Any otherwise illegal letter works here, but that might be changed. Vax BSD |
1864 | 4.2 assembler seems to allow any of @samp{defghDEFGH}.) | |
0b5b143a | 1865 | @end ignore |
f009d0ab RP |
1866 | |
1867 | On the H8/300, H8/500, | |
f009d0ab | 1868 | Hitachi SH, |
f009d0ab RP |
1869 | and AMD 29K architectures, the letter must be |
1870 | one of the letters @samp{DFPRSX} (in upper or lower case). | |
1871 | ||
3ffb03b1 | 1872 | On the ARC, the letter must be one of the letters @samp{DFRS} |
99c4053d | 1873 | (in upper or lower case). |
99c4053d | 1874 | |
f009d0ab RP |
1875 | On the Intel 960 architecture, the letter must be |
1876 | one of the letters @samp{DFT} (in upper or lower case). | |
9dcf8057 JL |
1877 | |
1878 | On the HPPA architecture, the letter must be @samp{E} (upper case only). | |
f009d0ab RP |
1879 | @end ifset |
1880 | @ifclear GENERIC | |
1881 | @ifset A29K | |
66b818fb | 1882 | One of the letters @samp{DFPRSX} (in upper or lower case). |
f009d0ab | 1883 | @end ifset |
99c4053d KR |
1884 | @ifset ARC |
1885 | One of the letters @samp{DFRS} (in upper or lower case). | |
1886 | @end ifset | |
f009d0ab RP |
1887 | @ifset H8 |
1888 | One of the letters @samp{DFPRSX} (in upper or lower case). | |
1889 | @end ifset | |
9dcf8057 | 1890 | @ifset HPPA |
05a0e43b | 1891 | The letter @samp{E} (upper case only). |
9dcf8057 | 1892 | @end ifset |
910d7df2 C |
1893 | @ifset I960 |
1894 | One of the letters @samp{DFT} (in upper or lower case). | |
1895 | @end ifset | |
f009d0ab RP |
1896 | @end ifclear |
1897 | ||
93b45514 RP |
1898 | @item |
1899 | An optional sign: either @samp{+} or @samp{-}. | |
f009d0ab | 1900 | |
93b45514 | 1901 | @item |
47342e8f | 1902 | An optional @dfn{integer part}: zero or more decimal digits. |
f009d0ab | 1903 | |
93b45514 | 1904 | @item |
66b818fb | 1905 | An optional @dfn{fractional part}: @samp{.} followed by zero |
93b45514 | 1906 | or more decimal digits. |
f009d0ab | 1907 | |
93b45514 RP |
1908 | @item |
1909 | An optional exponent, consisting of: | |
f009d0ab | 1910 | |
93b45514 RP |
1911 | @itemize @bullet |
1912 | @item | |
b50e59fe | 1913 | An @samp{E} or @samp{e}. |
d0281557 RP |
1914 | @c I can't find a config where "EXP_CHARS" is other than 'eE', but in |
1915 | @c principle this can perfectly well be different on different targets. | |
93b45514 RP |
1916 | @item |
1917 | Optional sign: either @samp{+} or @samp{-}. | |
1918 | @item | |
1919 | One or more decimal digits. | |
1920 | @end itemize | |
f009d0ab | 1921 | |
93b45514 RP |
1922 | @end itemize |
1923 | ||
66b818fb | 1924 | At least one of the integer part or the fractional part must be |
47342e8f | 1925 | present. The floating point number has the usual base-10 value. |
93b45514 | 1926 | |
f009d0ab | 1927 | @code{@value{AS}} does all processing using integers. Flonums are computed |
47342e8f | 1928 | independently of any floating point hardware in the computer running |
f009d0ab | 1929 | @code{@value{AS}}. |
d0281557 | 1930 | |
f009d0ab RP |
1931 | @ifclear GENERIC |
1932 | @ifset I960 | |
d0281557 RP |
1933 | @c Bit fields are written as a general facility but are also controlled |
1934 | @c by a conditional-compilation flag---which is as of now (21mar91) | |
1935 | @c turned on only by the i960 config of GAS. | |
242d9c06 | 1936 | @node Bit Fields |
d0281557 | 1937 | @subsubsection Bit Fields |
66b818fb RP |
1938 | |
1939 | @cindex bit fields | |
1940 | @cindex constants, bit field | |
d0281557 RP |
1941 | You can also define numeric constants as @dfn{bit fields}. |
1942 | specify two numbers separated by a colon--- | |
1943 | @example | |
1944 | @var{mask}:@var{value} | |
1945 | @end example | |
1946 | @noindent | |
05a0e43b RP |
1947 | @code{@value{AS}} applies a bitwise @sc{and} between @var{mask} and |
1948 | @var{value}. | |
d0281557 RP |
1949 | |
1950 | The resulting number is then packed | |
f009d0ab | 1951 | @ifset GENERIC |
7a4c8e5c | 1952 | @c this conditional paren in case bit fields turned on elsewhere than 960 |
d0281557 | 1953 | (in host-dependent byte order) |
f009d0ab | 1954 | @end ifset |
d0281557 RP |
1955 | into a field whose width depends on which assembler directive has the |
1956 | bit-field as its argument. Overflow (a result from the bitwise and | |
1957 | requiring more binary digits to represent) is not an error; instead, | |
1958 | more constants are generated, of the specified width, beginning with the | |
1959 | least significant digits.@refill | |
1960 | ||
1961 | The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long}, | |
1962 | @code{.short}, and @code{.word} accept bit-field arguments. | |
f009d0ab RP |
1963 | @end ifset |
1964 | @end ifclear | |
93b45514 | 1965 | |
242d9c06 | 1966 | @node Sections |
24b1493d | 1967 | @chapter Sections and Relocation |
66b818fb RP |
1968 | @cindex sections |
1969 | @cindex relocation | |
d0281557 | 1970 | |
7a4c8e5c | 1971 | @menu |
ba487f3a | 1972 | * Secs Background:: Background |
3ffb03b1 DE |
1973 | * Ld Sections:: Linker Sections |
1974 | * As Sections:: Assembler Internal Sections | |
ba487f3a RP |
1975 | * Sub-Sections:: Sub-Sections |
1976 | * bss:: bss Section | |
7a4c8e5c RP |
1977 | @end menu |
1978 | ||
242d9c06 | 1979 | @node Secs Background |
b50e59fe | 1980 | @section Background |
66b818fb | 1981 | |
24b1493d | 1982 | Roughly, a section is a range of addresses, with no gaps; all data |
d0281557 | 1983 | ``in'' those addresses is treated the same for some particular purpose. |
24b1493d | 1984 | For example there may be a ``read only'' section. |
93b45514 | 1985 | |
66b818fb RP |
1986 | @cindex linker, and assembler |
1987 | @cindex assembler, and linker | |
f009d0ab RP |
1988 | The linker @code{@value{LD}} reads many object files (partial programs) and |
1989 | combines their contents to form a runnable program. When @code{@value{AS}} | |
05a0e43b RP |
1990 | emits an object file, the partial program is assumed to start at address 0. |
1991 | @code{@value{LD}} assigns the final addresses for the partial program, so that | |
1992 | different partial programs do not overlap. This is actually an | |
1993 | oversimplification, but it suffices to explain how @code{@value{AS}} uses | |
1994 | sections. | |
93b45514 | 1995 | |
f009d0ab | 1996 | @code{@value{LD}} moves blocks of bytes of your program to their run-time |
93b45514 | 1997 | addresses. These blocks slide to their run-time addresses as rigid |
47342e8f | 1998 | units; their length does not change and neither does the order of bytes |
24b1493d RP |
1999 | within them. Such a rigid unit is called a @emph{section}. Assigning |
2000 | run-time addresses to sections is called @dfn{relocation}. It includes | |
47342e8f | 2001 | the task of adjusting mentions of object-file addresses so they refer to |
d0281557 | 2002 | the proper run-time addresses. |
f009d0ab RP |
2003 | @ifset H8 |
2004 | For the H8/300 and H8/500, | |
f009d0ab | 2005 | and for the Hitachi SH, |
f009d0ab RP |
2006 | @code{@value{AS}} pads sections if needed to |
2007 | ensure they end on a word (sixteen bit) boundary. | |
2008 | @end ifset | |
2009 | ||
3ffb03b1 | 2010 | @cindex standard assembler sections |
f009d0ab | 2011 | An object file written by @code{@value{AS}} has at least three sections, any |
24b1493d | 2012 | of which may be empty. These are named @dfn{text}, @dfn{data} and |
f009d0ab | 2013 | @dfn{bss} sections. |
93b45514 | 2014 | |
f009d0ab RP |
2015 | @ifset COFF |
2016 | @ifset GENERIC | |
2017 | When it generates COFF output, | |
2018 | @end ifset | |
2019 | @code{@value{AS}} can also generate whatever other named sections you specify | |
24b1493d | 2020 | using the @samp{.section} directive (@pxref{Section,,@code{.section}}). |
05a0e43b RP |
2021 | If you do not use any directives that place output in the @samp{.text} |
2022 | or @samp{.data} sections, these sections still exist, but are empty. | |
f009d0ab | 2023 | @end ifset |
d0281557 | 2024 | |
9dcf8057 JL |
2025 | @ifset HPPA |
2026 | @ifset GENERIC | |
2027 | When @code{@value{AS}} generates SOM or ELF output for the HPPA, | |
2028 | @end ifset | |
2029 | @code{@value{AS}} can also generate whatever other named sections you | |
2030 | specify using the @samp{.space} and @samp{.subspace} directives. See | |
2031 | @cite{HP9000 Series 800 Assembly Language Reference Manual} | |
2032 | (HP 92432-90001) for details on the @samp{.space} and @samp{.subspace} | |
2033 | assembler directives. | |
2034 | ||
2035 | @ifset SOM | |
2036 | Additionally, @code{@value{AS}} uses different names for the standard | |
2037 | text, data, and bss sections when generating SOM output. Program text | |
2038 | is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and | |
2039 | BSS into @samp{$BSS$}. | |
2040 | @end ifset | |
2041 | @end ifset | |
2042 | ||
24b1493d RP |
2043 | Within the object file, the text section starts at address @code{0}, the |
2044 | data section follows, and the bss section follows the data section. | |
d0281557 | 2045 | |
9dcf8057 JL |
2046 | @ifset HPPA |
2047 | When generating either SOM or ELF output files on the HPPA, the text | |
2048 | section starts at address @code{0}, the data section at address | |
2049 | @code{0x4000000}, and the bss section follows the data section. | |
2050 | @end ifset | |
2051 | ||
05a0e43b | 2052 | To let @code{@value{LD}} know which data changes when the sections are |
f009d0ab | 2053 | relocated, and how to change that data, @code{@value{AS}} also writes to the |
93b45514 | 2054 | object file details of the relocation needed. To perform relocation |
f009d0ab | 2055 | @code{@value{LD}} must know, each time an address in the object |
47342e8f | 2056 | file is mentioned: |
93b45514 RP |
2057 | @itemize @bullet |
2058 | @item | |
47342e8f RP |
2059 | Where in the object file is the beginning of this reference to |
2060 | an address? | |
93b45514 | 2061 | @item |
47342e8f | 2062 | How long (in bytes) is this reference? |
93b45514 | 2063 | @item |
24b1493d | 2064 | Which section does the address refer to? What is the numeric value of |
b50e59fe | 2065 | @display |
24b1493d | 2066 | (@var{address}) @minus{} (@var{start-address of section})? |
b50e59fe | 2067 | @end display |
93b45514 | 2068 | @item |
b50e59fe | 2069 | Is the reference to an address ``Program-Counter relative''? |
93b45514 RP |
2070 | @end itemize |
2071 | ||
66b818fb RP |
2072 | @cindex addresses, format of |
2073 | @cindex section-relative addressing | |
f009d0ab | 2074 | In fact, every address @code{@value{AS}} ever uses is expressed as |
d0281557 | 2075 | @display |
24b1493d | 2076 | (@var{section}) + (@var{offset into section}) |
d0281557 RP |
2077 | @end display |
2078 | @noindent | |
65fbb2d7 RP |
2079 | Further, most expressions @code{@value{AS}} computes have this section-relative |
2080 | nature. | |
2081 | @ifset SOM | |
2082 | (For some object formats, such as SOM for the HPPA, some expressions are | |
2083 | symbol-relative instead.) | |
2084 | @end ifset | |
dd565f85 RP |
2085 | |
2086 | In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset | |
2087 | @var{N} into section @var{secname}.'' | |
24b1493d RP |
2088 | |
2089 | Apart from text, data and bss sections you need to know about the | |
f009d0ab | 2090 | @dfn{absolute} section. When @code{@value{LD}} mixes partial programs, |
66b818fb | 2091 | addresses in the absolute section remain unchanged. For example, address |
05a0e43b RP |
2092 | @code{@{absolute 0@}} is ``relocated'' to run-time address 0 by |
2093 | @code{@value{LD}}. Although the linker never arranges two partial programs' | |
2094 | data sections with overlapping addresses after linking, @emph{by definition} | |
2095 | their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one | |
2096 | part of a program is always the same address when the program is running as | |
2097 | address @code{@{absolute@ 239@}} in any other part of the program. | |
47342e8f | 2098 | |
24b1493d RP |
2099 | The idea of sections is extended to the @dfn{undefined} section. Any |
2100 | address whose section is unknown at assembly time is by definition | |
05a0e43b | 2101 | rendered @{undefined @var{U}@}---where @var{U} is filled in later. |
47342e8f | 2102 | Since numbers are always defined, the only way to generate an undefined |
93b45514 RP |
2103 | address is to mention an undefined symbol. A reference to a named |
2104 | common block would be such a symbol: its value is unknown at assembly | |
24b1493d | 2105 | time so it has section @emph{undefined}. |
93b45514 | 2106 | |
24b1493d | 2107 | By analogy the word @emph{section} is used to describe groups of sections in |
f009d0ab | 2108 | the linked program. @code{@value{LD}} puts all partial programs' text |
24b1493d RP |
2109 | sections in contiguous addresses in the linked program. It is |
2110 | customary to refer to the @emph{text section} of a program, meaning all | |
05a0e43b | 2111 | the addresses of all partial programs' text sections. Likewise for |
24b1493d | 2112 | data and bss sections. |
93b45514 | 2113 | |
f009d0ab RP |
2114 | Some sections are manipulated by @code{@value{LD}}; others are invented for |
2115 | use of @code{@value{AS}} and have no meaning except during assembly. | |
47342e8f | 2116 | |
f009d0ab | 2117 | @node Ld Sections |
3ffb03b1 | 2118 | @section Linker Sections |
f009d0ab | 2119 | @code{@value{LD}} deals with just four kinds of sections, summarized below. |
b50e59fe RP |
2120 | |
2121 | @table @strong | |
47342e8f | 2122 | |
f009d0ab | 2123 | @ifset COFF |
66b818fb RP |
2124 | @cindex named sections |
2125 | @cindex sections, named | |
24b1493d | 2126 | @item named sections |
f009d0ab RP |
2127 | @end ifset |
2128 | @ifset aout-bout | |
66b818fb RP |
2129 | @cindex text section |
2130 | @cindex data section | |
9dcf8057 | 2131 | @itemx text section |
24b1493d | 2132 | @itemx data section |
f009d0ab RP |
2133 | @end ifset |
2134 | These sections hold your program. @code{@value{AS}} and @code{@value{LD}} treat them as | |
24b1493d | 2135 | separate but equal sections. Anything you can say of one section is |
f009d0ab RP |
2136 | true another. |
2137 | @ifset aout-bout | |
24b1493d RP |
2138 | When the program is running, however, it is |
2139 | customary for the text section to be unalterable. The | |
05a0e43b | 2140 | text section is often shared among processes: it contains |
24b1493d | 2141 | instructions, constants and the like. The data section of a running |
b50e59fe | 2142 | program is usually alterable: for example, C variables would be stored |
24b1493d | 2143 | in the data section. |
f009d0ab | 2144 | @end ifset |
47342e8f | 2145 | |
66b818fb | 2146 | @cindex bss section |
24b1493d RP |
2147 | @item bss section |
2148 | This section contains zeroed bytes when your program begins running. It | |
47342e8f | 2149 | is used to hold unitialized variables or common storage. The length of |
24b1493d | 2150 | each partial program's bss section is important, but because it starts |
47342e8f | 2151 | out containing zeroed bytes there is no need to store explicit zero |
24b1493d | 2152 | bytes in the object file. The bss section was invented to eliminate |
d0281557 | 2153 | those explicit zeros from object files. |
47342e8f | 2154 | |
66b818fb | 2155 | @cindex absolute section |
24b1493d RP |
2156 | @item absolute section |
2157 | Address 0 of this section is always ``relocated'' to runtime address 0. | |
f009d0ab | 2158 | This is useful if you want to refer to an address that @code{@value{LD}} must |
47342e8f | 2159 | not change when relocating. In this sense we speak of absolute |
05a0e43b | 2160 | addresses being ``unrelocatable'': they do not change during relocation. |
47342e8f | 2161 | |
66b818fb | 2162 | @cindex undefined section |
24b1493d RP |
2163 | @item undefined section |
2164 | This ``section'' is a catch-all for address references to objects not in | |
2165 | the preceding sections. | |
47342e8f | 2166 | @c FIXME: ref to some other doc on obj-file formats could go here. |
93b45514 | 2167 | @end table |
47342e8f | 2168 | |
66b818fb | 2169 | @cindex relocation example |
f009d0ab RP |
2170 | An idealized example of three relocatable sections follows. |
2171 | @ifset COFF | |
66b818fb | 2172 | The example uses the traditional section names @samp{.text} and @samp{.data}. |
f009d0ab | 2173 | @end ifset |
24b1493d | 2174 | Memory addresses are on the horizontal axis. |
93b45514 | 2175 | |
7d7ecbdd | 2176 | @c TEXI2ROFF-KILL |
b50e59fe | 2177 | @ifinfo |
7d7ecbdd | 2178 | @c END TEXI2ROFF-KILL |
d0281557 | 2179 | @smallexample |
93b45514 RP |
2180 | +-----+----+--+ |
2181 | partial program # 1: |ttttt|dddd|00| | |
2182 | +-----+----+--+ | |
2183 | ||
2184 | text data bss | |
2185 | seg. seg. seg. | |
2186 | ||
2187 | +---+---+---+ | |
2188 | partial program # 2: |TTT|DDD|000| | |
2189 | +---+---+---+ | |
2190 | ||
2191 | +--+---+-----+--+----+---+-----+~~ | |
2192 | linked program: | |TTT|ttttt| |dddd|DDD|00000| | |
2193 | +--+---+-----+--+----+---+-----+~~ | |
2194 | ||
2195 | addresses: 0 @dots{} | |
d0281557 | 2196 | @end smallexample |
7d7ecbdd | 2197 | @c TEXI2ROFF-KILL |
b50e59fe | 2198 | @end ifinfo |
8babef85 | 2199 | @need 5000 |
b50e59fe | 2200 | @tex |
d0281557 | 2201 | |
66b818fb | 2202 | \line{\it Partial program \#1: \hfil} |
d0281557 RP |
2203 | \line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil} |
2204 | \line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil} | |
2205 | ||
66b818fb | 2206 | \line{\it Partial program \#2: \hfil} |
d0281557 RP |
2207 | \line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil} |
2208 | \line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil} | |
2209 | ||
66b818fb | 2210 | \line{\it linked program: \hfil} |
d0281557 RP |
2211 | \line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil} |
2212 | \line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt | |
b50e59fe | 2213 | ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt |
d0281557 RP |
2214 | DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil} |
2215 | ||
66b818fb | 2216 | \line{\it addresses: \hfil} |
d0281557 RP |
2217 | \line{0\dots\hfil} |
2218 | ||
b50e59fe | 2219 | @end tex |
7d7ecbdd | 2220 | @c END TEXI2ROFF-KILL |
93b45514 | 2221 | |
f009d0ab | 2222 | @node As Sections |
3ffb03b1 | 2223 | @section Assembler Internal Sections |
66b818fb | 2224 | |
3ffb03b1 | 2225 | @cindex internal assembler sections |
66b818fb | 2226 | @cindex sections in messages, internal |
f009d0ab | 2227 | These sections are meant only for the internal use of @code{@value{AS}}. They |
05a0e43b | 2228 | have no meaning at run-time. You do not really need to know about these |
f009d0ab | 2229 | sections for most purposes; but they can be mentioned in @code{@value{AS}} |
24b1493d | 2230 | warning messages, so it might be helpful to have an idea of their |
f009d0ab | 2231 | meanings to @code{@value{AS}}. These sections are used to permit the |
24b1493d RP |
2232 | value of every expression in your assembly language program to be a |
2233 | section-relative address. | |
93b45514 | 2234 | |
d0281557 | 2235 | @table @b |
66b818fb | 2236 | @cindex assembler internal logic error |
71dd3c40 | 2237 | @item ASSEMBLER-INTERNAL-LOGIC-ERROR! |
24b1493d RP |
2238 | An internal assembler logic error has been found. This means there is a |
2239 | bug in the assembler. | |
2240 | ||
9dcf8057 | 2241 | @cindex expr (internal section) |
71dd3c40 | 2242 | @item expr section |
9dcf8057 JL |
2243 | The assembler stores complex expression internally as combinations of |
2244 | symbols. When it needs to represent an expression as a symbol, it puts | |
2245 | it in the expr section. | |
24b1493d RP |
2246 | @c FIXME item debug |
2247 | @c FIXME item transfer[t] vector preload | |
2248 | @c FIXME item transfer[t] vector postload | |
2249 | @c FIXME item register | |
93b45514 RP |
2250 | @end table |
2251 | ||
242d9c06 | 2252 | @node Sub-Sections |
24b1493d | 2253 | @section Sub-Sections |
66b818fb RP |
2254 | |
2255 | @cindex numbered subsections | |
2256 | @cindex grouping data | |
f009d0ab | 2257 | @ifset aout-bout |
24b1493d | 2258 | Assembled bytes |
f009d0ab | 2259 | @ifset COFF |
24b1493d | 2260 | conventionally |
f009d0ab RP |
2261 | @end ifset |
2262 | fall into two sections: text and data. | |
2263 | @end ifset | |
66b818fb | 2264 | You may have separate groups of |
f009d0ab | 2265 | @ifset GENERIC |
66b818fb | 2266 | data in named sections |
f009d0ab RP |
2267 | @end ifset |
2268 | @ifclear GENERIC | |
2269 | @ifclear aout-bout | |
2270 | data in named sections | |
2271 | @end ifclear | |
2272 | @ifset aout-bout | |
2273 | text or data | |
2274 | @end ifset | |
2275 | @end ifclear | |
05a0e43b RP |
2276 | that you want to end up near to each other in the object file, even though they |
2277 | are not contiguous in the assembler source. @code{@value{AS}} allows you to | |
2278 | use @dfn{subsections} for this purpose. Within each section, there can be | |
2279 | numbered subsections with values from 0 to 8192. Objects assembled into the | |
2280 | same subsection go into the object file together with other objects in the same | |
2281 | subsection. For example, a compiler might want to store constants in the text | |
2282 | section, but might not want to have them interspersed with the program being | |
2283 | assembled. In this case, the compiler could issue a @samp{.text 0} before each | |
2284 | section of code being output, and a @samp{.text 1} before each group of | |
2285 | constants being output. | |
2286 | ||
2287 | Subsections are optional. If you do not use subsections, everything | |
2288 | goes in subsection number zero. | |
93b45514 | 2289 | |
f009d0ab | 2290 | @ifset GENERIC |
24b1493d RP |
2291 | Each subsection is zero-padded up to a multiple of four bytes. |
2292 | (Subsections may be padded a different amount on different flavors | |
f009d0ab RP |
2293 | of @code{@value{AS}}.) |
2294 | @end ifset | |
2295 | @ifclear GENERIC | |
2296 | @ifset H8 | |
2297 | On the H8/300 and H8/500 platforms, each subsection is zero-padded to a word | |
66b818fb | 2298 | boundary (two bytes). |
f009d0ab | 2299 | The same is true on the Hitachi SH. |
f009d0ab RP |
2300 | @end ifset |
2301 | @ifset I960 | |
24b1493d | 2302 | @c FIXME section padding (alignment)? |
d0281557 RP |
2303 | @c Rich Pixley says padding here depends on target obj code format; that |
2304 | @c doesn't seem particularly useful to say without further elaboration, | |
2305 | @c so for now I say nothing about it. If this is a generic BFD issue, | |
2306 | @c these paragraphs might need to vanish from this manual, and be | |
2307 | @c discussed in BFD chapter of binutils (or some such). | |
f009d0ab RP |
2308 | @end ifset |
2309 | @ifset A29K | |
66b818fb | 2310 | On the AMD 29K family, no particular padding is added to section or |
f009d0ab RP |
2311 | subsection sizes; @value{AS} forces no alignment on this platform. |
2312 | @end ifset | |
2313 | @end ifclear | |
66b818fb | 2314 | |
24b1493d | 2315 | Subsections appear in your object file in numeric order, lowest numbered |
b50e59fe | 2316 | to highest. (All this to be compatible with other people's assemblers.) |
f009d0ab | 2317 | The object file contains no representation of subsections; @code{@value{LD}} and |
05a0e43b | 2318 | other programs that manipulate object files see no trace of them. |
24b1493d RP |
2319 | They just see all your text subsections as a text section, and all your |
2320 | data subsections as a data section. | |
93b45514 | 2321 | |
24b1493d | 2322 | To specify which subsection you want subsequent statements assembled |
66b818fb RP |
2323 | into, use a numeric argument to specify it, in a @samp{.text |
2324 | @var{expression}} or a @samp{.data @var{expression}} statement. | |
f009d0ab RP |
2325 | @ifset COFF |
2326 | @ifset GENERIC | |
2327 | When generating COFF output, you | |
2328 | @end ifset | |
2329 | @ifclear GENERIC | |
66b818fb | 2330 | You |
f009d0ab | 2331 | @end ifclear |
66b818fb RP |
2332 | can also use an extra subsection |
2333 | argument with arbitrary named sections: @samp{.section @var{name}, | |
2334 | @var{expression}}. | |
f009d0ab | 2335 | @end ifset |
66b818fb RP |
2336 | @var{Expression} should be an absolute expression. |
2337 | (@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0} | |
2338 | is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly | |
2339 | begins in @code{text 0}. For instance: | |
d0281557 | 2340 | @smallexample |
24b1493d RP |
2341 | .text 0 # The default subsection is text 0 anyway. |
2342 | .ascii "This lives in the first text subsection. *" | |
93b45514 | 2343 | .text 1 |
24b1493d | 2344 | .ascii "But this lives in the second text subsection." |
93b45514 | 2345 | .data 0 |
24b1493d RP |
2346 | .ascii "This lives in the data section," |
2347 | .ascii "in the first data subsection." | |
93b45514 | 2348 | .text 0 |
24b1493d | 2349 | .ascii "This lives in the first text section," |
93b45514 | 2350 | .ascii "immediately following the asterisk (*)." |
d0281557 | 2351 | @end smallexample |
93b45514 | 2352 | |
05a0e43b RP |
2353 | Each section has a @dfn{location counter} incremented by one for every byte |
2354 | assembled into that section. Because subsections are merely a convenience | |
2355 | restricted to @code{@value{AS}} there is no concept of a subsection location | |
2356 | counter. There is no way to directly manipulate a location counter---but the | |
2357 | @code{.align} directive changes it, and any label definition captures its | |
2358 | current value. The location counter of the section where statements are being | |
2359 | assembled is said to be the @dfn{active} location counter. | |
93b45514 | 2360 | |
242d9c06 | 2361 | @node bss |
24b1493d | 2362 | @section bss Section |
66b818fb RP |
2363 | |
2364 | @cindex bss section | |
2365 | @cindex common variable storage | |
24b1493d RP |
2366 | The bss section is used for local common variable storage. |
2367 | You may allocate address space in the bss section, but you may | |
93b45514 | 2368 | not dictate data to load into it before your program executes. When |
b50e59fe | 2369 | your program starts running, all the contents of the bss |
24b1493d | 2370 | section are zeroed bytes. |
93b45514 | 2371 | |
35cfacf0 ILT |
2372 | The @code{.lcomm} pseudo-op defines a symbol in the bss section; see |
2373 | @ref{Lcomm,,@code{.lcomm}}. | |
2374 | ||
2375 | The @code{.comm} pseudo-op may be used to declare a common symbol, which is | |
2376 | another form of uninitialized symbol; see @xref{Comm,,@code{.comm}}. | |
2377 | ||
2378 | @ifset GENERIC | |
2379 | When assembling for a target which supports multiple sections, such as ELF or | |
2380 | COFF, you may switch into the @code{.bss} section and define symbols as usual; | |
2381 | see @ref{Section,,@code{.section}}. You may only assemble zero values into the | |
2382 | section. Typically the section will only contain symbol definitions and | |
2383 | @code{.skip} directives (@pxref{Skip,,@code{.skip}}). | |
2384 | @end ifset | |
93b45514 | 2385 | |
242d9c06 | 2386 | @node Symbols |
93b45514 | 2387 | @chapter Symbols |
66b818fb RP |
2388 | |
2389 | @cindex symbols | |
47342e8f RP |
2390 | Symbols are a central concept: the programmer uses symbols to name |
2391 | things, the linker uses symbols to link, and the debugger uses symbols | |
d0281557 | 2392 | to debug. |
47342e8f | 2393 | |
b50e59fe | 2394 | @quotation |
66b818fb | 2395 | @cindex debuggers, and symbol order |
f009d0ab | 2396 | @emph{Warning:} @code{@value{AS}} does not place symbols in the object file in |
b50e59fe RP |
2397 | the same order they were declared. This may break some debuggers. |
2398 | @end quotation | |
93b45514 | 2399 | |
7a4c8e5c | 2400 | @menu |
ba487f3a RP |
2401 | * Labels:: Labels |
2402 | * Setting Symbols:: Giving Symbols Other Values | |
2403 | * Symbol Names:: Symbol Names | |
2404 | * Dot:: The Special Dot Symbol | |
2405 | * Symbol Attributes:: Symbol Attributes | |
7a4c8e5c RP |
2406 | @end menu |
2407 | ||
242d9c06 | 2408 | @node Labels |
93b45514 | 2409 | @section Labels |
66b818fb RP |
2410 | |
2411 | @cindex labels | |
93b45514 | 2412 | A @dfn{label} is written as a symbol immediately followed by a colon |
b50e59fe | 2413 | @samp{:}. The symbol then represents the current value of the |
93b45514 RP |
2414 | active location counter, and is, for example, a suitable instruction |
2415 | operand. You are warned if you use the same symbol to represent two | |
2416 | different locations: the first definition overrides any other | |
2417 | definitions. | |
2418 | ||
9dcf8057 | 2419 | @ifset HPPA |
81fcb3ff RP |
2420 | On the HPPA, the usual form for a label need not be immediately followed by a |
2421 | colon, but instead must start in column zero. Only one label may be defined on | |
2422 | a single line. To work around this, the HPPA version of @code{@value{AS}} also | |
2423 | provides a special directive @code{.label} for defining labels more flexibly. | |
9dcf8057 JL |
2424 | @end ifset |
2425 | ||
242d9c06 | 2426 | @node Setting Symbols |
93b45514 | 2427 | @section Giving Symbols Other Values |
66b818fb RP |
2428 | |
2429 | @cindex assigning values to symbols | |
2430 | @cindex symbol values, assigning | |
b50e59fe RP |
2431 | A symbol can be given an arbitrary value by writing a symbol, followed |
2432 | by an equals sign @samp{=}, followed by an expression | |
93b45514 | 2433 | (@pxref{Expressions}). This is equivalent to using the @code{.set} |
7a4c8e5c | 2434 | directive. @xref{Set,,@code{.set}}. |
93b45514 | 2435 | |
242d9c06 | 2436 | @node Symbol Names |
93b45514 | 2437 | @section Symbol Names |
66b818fb RP |
2438 | |
2439 | @cindex symbol names | |
2440 | @cindex names, symbol | |
f009d0ab RP |
2441 | @ifclear SPECIAL-SYMS |
2442 | Symbol names begin with a letter or with one of @samp{._}. On most | |
2443 | machines, you can also use @code{$} in symbol names; exceptions are | |
2444 | noted in @ref{Machine Dependencies}. That character may be followed by any | |
2445 | string of digits, letters, dollar signs (unless otherwise noted in | |
2446 | @ref{Machine Dependencies}), and underscores. | |
2447 | @end ifclear | |
2448 | @ifset A29K | |
b50e59fe RP |
2449 | For the AMD 29K family, @samp{?} is also allowed in the |
2450 | body of a symbol name, though not at its beginning. | |
f009d0ab RP |
2451 | @end ifset |
2452 | ||
2453 | @ifset SPECIAL-SYMS | |
2454 | @ifset H8 | |
2455 | Symbol names begin with a letter or with one of @samp{._}. On the | |
f009d0ab | 2456 | Hitachi SH or the |
f009d0ab RP |
2457 | H8/500, you can also use @code{$} in symbol names. That character may |
2458 | be followed by any string of digits, letters, dollar signs (save on the | |
2459 | H8/300), and underscores. | |
2460 | @end ifset | |
2461 | @end ifset | |
2462 | ||
2463 | Case of letters is significant: @code{foo} is a different symbol name | |
2464 | than @code{Foo}. | |
b50e59fe | 2465 | |
05a0e43b RP |
2466 | Each symbol has exactly one name. Each name in an assembly language program |
2467 | refers to exactly one symbol. You may use that symbol name any number of times | |
2468 | in a program. | |
93b45514 | 2469 | |
7a4c8e5c | 2470 | @subheading Local Symbol Names |
93b45514 | 2471 | |
66b818fb RP |
2472 | @cindex local symbol names |
2473 | @cindex symbol names, local | |
2474 | @cindex temporary symbol names | |
2475 | @cindex symbol names, temporary | |
93b45514 | 2476 | Local symbols help compilers and programmers use names temporarily. |
b50e59fe RP |
2477 | There are ten local symbol names, which are re-used throughout the |
2478 | program. You may refer to them using the names @samp{0} @samp{1} | |
2479 | @dots{} @samp{9}. To define a local symbol, write a label of the form | |
2480 | @samp{@b{N}:} (where @b{N} represents any digit). To refer to the most | |
2481 | recent previous definition of that symbol write @samp{@b{N}b}, using the | |
2482 | same digit as when you defined the label. To refer to the next | |
2483 | definition of a local label, write @samp{@b{N}f}---where @b{N} gives you | |
2484 | a choice of 10 forward references. The @samp{b} stands for | |
2485 | ``backwards'' and the @samp{f} stands for ``forwards''. | |
2486 | ||
8babef85 | 2487 | Local symbols are not emitted by the current @sc{gnu} C compiler. |
93b45514 RP |
2488 | |
2489 | There is no restriction on how you can use these labels, but | |
2490 | remember that at any point in the assembly you can refer to at most | |
2491 | 10 prior local labels and to at most 10 forward local labels. | |
2492 | ||
47342e8f | 2493 | Local symbol names are only a notation device. They are immediately |
93b45514 | 2494 | transformed into more conventional symbol names before the assembler |
47342e8f RP |
2495 | uses them. The symbol names stored in the symbol table, appearing in |
2496 | error messages and optionally emitted to the object file have these | |
2497 | parts: | |
2498 | ||
2499 | @table @code | |
93b45514 | 2500 | @item L |
f009d0ab RP |
2501 | All local labels begin with @samp{L}. Normally both @code{@value{AS}} and |
2502 | @code{@value{LD}} forget symbols that start with @samp{L}. These labels are | |
05a0e43b RP |
2503 | used for symbols you are never intended to see. If you use the |
2504 | @samp{-L} option then @code{@value{AS}} retains these symbols in the | |
f009d0ab | 2505 | object file. If you also instruct @code{@value{LD}} to retain these symbols, |
93b45514 | 2506 | you may use them in debugging. |
47342e8f RP |
2507 | |
2508 | @item @var{digit} | |
93b45514 RP |
2509 | If the label is written @samp{0:} then the digit is @samp{0}. |
2510 | If the label is written @samp{1:} then the digit is @samp{1}. | |
2511 | And so on up through @samp{9:}. | |
47342e8f | 2512 | |
35cfacf0 | 2513 | @item @kbd{C-A} |
05a0e43b | 2514 | This unusual character is included so you do not accidentally invent |
93b45514 RP |
2515 | a symbol of the same name. The character has ASCII value |
2516 | @samp{\001}. | |
47342e8f RP |
2517 | |
2518 | @item @emph{ordinal number} | |
2519 | This is a serial number to keep the labels distinct. The first | |
93b45514 | 2520 | @samp{0:} gets the number @samp{1}; The 15th @samp{0:} gets the |
47342e8f | 2521 | number @samp{15}; @emph{etc.}. Likewise for the other labels @samp{1:} |
93b45514 RP |
2522 | through @samp{9:}. |
2523 | @end table | |
47342e8f | 2524 | |
35cfacf0 ILT |
2525 | For instance, the first @code{1:} is named @code{L1@kbd{C-A}1}, the 44th |
2526 | @code{3:} is named @code{L3@kbd{C-A}44}. | |
93b45514 | 2527 | |
242d9c06 | 2528 | @node Dot |
93b45514 RP |
2529 | @section The Special Dot Symbol |
2530 | ||
66b818fb RP |
2531 | @cindex dot (symbol) |
2532 | @cindex @code{.} (symbol) | |
2533 | @cindex current address | |
2534 | @cindex location counter | |
b50e59fe | 2535 | The special symbol @samp{.} refers to the current address that |
f009d0ab | 2536 | @code{@value{AS}} is assembling into. Thus, the expression @samp{melvin: |
05a0e43b | 2537 | .long .} defines @code{melvin} to contain its own address. |
93b45514 RP |
2538 | Assigning a value to @code{.} is treated the same as a @code{.org} |
2539 | directive. Thus, the expression @samp{.=.+4} is the same as saying | |
f009d0ab | 2540 | @ifclear no-space-dir |
09352a5d | 2541 | @samp{.space 4}. |
f009d0ab RP |
2542 | @end ifclear |
2543 | @ifset no-space-dir | |
2544 | @ifset A29K | |
b50e59fe | 2545 | @samp{.block 4}. |
f009d0ab RP |
2546 | @end ifset |
2547 | @end ifset | |
b50e59fe | 2548 | |
242d9c06 | 2549 | @node Symbol Attributes |
93b45514 | 2550 | @section Symbol Attributes |
66b818fb RP |
2551 | |
2552 | @cindex symbol attributes | |
2553 | @cindex attributes, symbol | |
d0281557 | 2554 | Every symbol has, as well as its name, the attributes ``Value'' and |
66b818fb | 2555 | ``Type''. Depending on output format, symbols can also have auxiliary |
f009d0ab RP |
2556 | attributes. |
2557 | @ifset INTERNALS | |
2558 | The detailed definitions are in @file{a.out.h}. | |
2559 | @end ifset | |
93b45514 | 2560 | |
f009d0ab | 2561 | If you use a symbol without defining it, @code{@value{AS}} assumes zero for |
93b45514 RP |
2562 | all these attributes, and probably won't warn you. This makes the |
2563 | symbol an externally defined symbol, which is generally what you | |
2564 | would want. | |
2565 | ||
7a4c8e5c | 2566 | @menu |
ba487f3a RP |
2567 | * Symbol Value:: Value |
2568 | * Symbol Type:: Type | |
f009d0ab RP |
2569 | @ifset aout-bout |
2570 | @ifset GENERIC | |
2571 | * a.out Symbols:: Symbol Attributes: @code{a.out} | |
2572 | @end ifset | |
2573 | @ifclear GENERIC | |
2574 | @ifclear BOUT | |
ba487f3a | 2575 | * a.out Symbols:: Symbol Attributes: @code{a.out} |
f009d0ab RP |
2576 | @end ifclear |
2577 | @ifset BOUT | |
ba487f3a | 2578 | * a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out} |
f009d0ab RP |
2579 | @end ifset |
2580 | @end ifclear | |
2581 | @end ifset | |
2582 | @ifset COFF | |
ba487f3a | 2583 | * COFF Symbols:: Symbol Attributes for COFF |
f009d0ab | 2584 | @end ifset |
9dcf8057 JL |
2585 | @ifset SOM |
2586 | * SOM Symbols:: Symbol Attributes for SOM | |
2587 | @end ifset | |
7a4c8e5c RP |
2588 | @end menu |
2589 | ||
242d9c06 | 2590 | @node Symbol Value |
93b45514 | 2591 | @subsection Value |
66b818fb RP |
2592 | |
2593 | @cindex value of a symbol | |
2594 | @cindex symbol value | |
24b1493d RP |
2595 | The value of a symbol is (usually) 32 bits. For a symbol which labels a |
2596 | location in the text, data, bss or absolute sections the value is the | |
2597 | number of addresses from the start of that section to the label. | |
2598 | Naturally for text, data and bss sections the value of a symbol changes | |
f009d0ab | 2599 | as @code{@value{LD}} changes section base addresses during linking. Absolute |
24b1493d RP |
2600 | symbols' values do not change during linking: that is why they are |
2601 | called absolute. | |
93b45514 | 2602 | |
b50e59fe | 2603 | The value of an undefined symbol is treated in a special way. If it is |
05a0e43b RP |
2604 | 0 then the symbol is not defined in this assembler source file, and |
2605 | @code{@value{LD}} tries to determine its value from other files linked into the | |
2606 | same program. You make this kind of symbol simply by mentioning a symbol | |
b50e59fe RP |
2607 | name without defining it. A non-zero value represents a @code{.comm} |
2608 | common declaration. The value is how much common storage to reserve, in | |
2609 | bytes (addresses). The symbol refers to the first address of the | |
2610 | allocated storage. | |
93b45514 | 2611 | |
242d9c06 | 2612 | @node Symbol Type |
93b45514 | 2613 | @subsection Type |
66b818fb RP |
2614 | |
2615 | @cindex type of a symbol | |
2616 | @cindex symbol type | |
24b1493d | 2617 | The type attribute of a symbol contains relocation (section) |
d0281557 RP |
2618 | information, any flag settings indicating that a symbol is external, and |
2619 | (optionally), other information for linkers and debuggers. The exact | |
2620 | format depends on the object-code output format in use. | |
93b45514 | 2621 | |
f009d0ab RP |
2622 | @ifset aout-bout |
2623 | @ifclear GENERIC | |
2624 | @ifset BOUT | |
2625 | @c The following avoids a "widow" subsection title. @group would be | |
2626 | @c better if it were available outside examples. | |
2627 | @need 1000 | |
242d9c06 | 2628 | @node a.out Symbols |
d0281557 | 2629 | @subsection Symbol Attributes: @code{a.out}, @code{b.out} |
66b818fb RP |
2630 | |
2631 | @cindex @code{b.out} symbol attributes | |
2632 | @cindex symbol attributes, @code{b.out} | |
f009d0ab RP |
2633 | These symbol attributes appear only when @code{@value{AS}} is configured for |
2634 | one of the Berkeley-descended object output formats---@code{a.out} or | |
2635 | @code{b.out}. | |
2636 | ||
2637 | @end ifset | |
2638 | @ifclear BOUT | |
2639 | @node a.out Symbols | |
2640 | @subsection Symbol Attributes: @code{a.out} | |
2641 | ||
2642 | @cindex @code{a.out} symbol attributes | |
2643 | @cindex symbol attributes, @code{a.out} | |
2644 | ||
2645 | @end ifclear | |
2646 | @end ifclear | |
2647 | @ifset GENERIC | |
2648 | @node a.out Symbols | |
0b5b143a | 2649 | @subsection Symbol Attributes: @code{a.out} |
7a4c8e5c | 2650 | |
66b818fb RP |
2651 | @cindex @code{a.out} symbol attributes |
2652 | @cindex symbol attributes, @code{a.out} | |
2653 | ||
f009d0ab | 2654 | @end ifset |
7a4c8e5c | 2655 | @menu |
ba487f3a RP |
2656 | * Symbol Desc:: Descriptor |
2657 | * Symbol Other:: Other | |
7a4c8e5c | 2658 | @end menu |
93b45514 | 2659 | |
242d9c06 | 2660 | @node Symbol Desc |
d0281557 | 2661 | @subsubsection Descriptor |
66b818fb RP |
2662 | |
2663 | @cindex descriptor, of @code{a.out} symbol | |
93b45514 | 2664 | This is an arbitrary 16-bit value. You may establish a symbol's |
7a4c8e5c RP |
2665 | descriptor value by using a @code{.desc} statement |
2666 | (@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to | |
f009d0ab | 2667 | @code{@value{AS}}. |
93b45514 | 2668 | |
242d9c06 | 2669 | @node Symbol Other |
d0281557 | 2670 | @subsubsection Other |
66b818fb RP |
2671 | |
2672 | @cindex other attribute, of @code{a.out} symbol | |
f009d0ab RP |
2673 | This is an arbitrary 8-bit value. It means nothing to @code{@value{AS}}. |
2674 | @end ifset | |
d0281557 | 2675 | |
f009d0ab | 2676 | @ifset COFF |
242d9c06 | 2677 | @node COFF Symbols |
d0281557 | 2678 | @subsection Symbol Attributes for COFF |
66b818fb RP |
2679 | |
2680 | @cindex COFF symbol attributes | |
2681 | @cindex symbol attributes, COFF | |
2682 | ||
d0281557 RP |
2683 | The COFF format supports a multitude of auxiliary symbol attributes; |
2684 | like the primary symbol attributes, they are set between @code{.def} and | |
f009d0ab | 2685 | @code{.endef} directives. |
d0281557 RP |
2686 | |
2687 | @subsubsection Primary Attributes | |
66b818fb RP |
2688 | |
2689 | @cindex primary attributes, COFF symbols | |
d0281557 RP |
2690 | The symbol name is set with @code{.def}; the value and type, |
2691 | respectively, with @code{.val} and @code{.type}. | |
2692 | ||
2693 | @subsubsection Auxiliary Attributes | |
66b818fb RP |
2694 | |
2695 | @cindex auxiliary attributes, COFF symbols | |
f009d0ab | 2696 | The @code{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl}, |
d0281557 RP |
2697 | @code{.size}, and @code{.tag} can generate auxiliary symbol table |
2698 | information for COFF. | |
f009d0ab | 2699 | @end ifset |
93b45514 | 2700 | |
9dcf8057 JL |
2701 | @ifset SOM |
2702 | @node SOM Symbols | |
2703 | @subsection Symbol Attributes for SOM | |
2704 | ||
2705 | @cindex SOM symbol attributes | |
2706 | @cindex symbol attributes, SOM | |
2707 | ||
05a0e43b RP |
2708 | The SOM format for the HPPA supports a multitude of symbol attributes set with |
2709 | the @code{.EXPORT} and @code{.IMPORT} directives. | |
9dcf8057 JL |
2710 | |
2711 | The attributes are described in @cite{HP9000 Series 800 Assembly | |
2712 | Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and | |
2713 | @code{EXPORT} assembler directive documentation. | |
2714 | @end ifset | |
2715 | ||
242d9c06 | 2716 | @node Expressions |
93b45514 | 2717 | @chapter Expressions |
66b818fb RP |
2718 | |
2719 | @cindex expressions | |
2720 | @cindex addresses | |
2721 | @cindex numeric values | |
93b45514 RP |
2722 | An @dfn{expression} specifies an address or numeric value. |
2723 | Whitespace may precede and/or follow an expression. | |
2724 | ||
dd565f85 RP |
2725 | The result of an expression must be an absolute number, or else an offset into |
2726 | a particular section. If an expression is not absolute, and there is not | |
2727 | enough information when @code{@value{AS}} sees the expression to know its | |
2728 | section, a second pass over the source program might be necessary to interpret | |
2729 | the expression---but the second pass is currently not implemented. | |
2730 | @code{@value{AS}} aborts with an error message in this situation. | |
2731 | ||
7a4c8e5c | 2732 | @menu |
ba487f3a RP |
2733 | * Empty Exprs:: Empty Expressions |
2734 | * Integer Exprs:: Integer Expressions | |
7a4c8e5c RP |
2735 | @end menu |
2736 | ||
242d9c06 | 2737 | @node Empty Exprs |
93b45514 | 2738 | @section Empty Expressions |
66b818fb RP |
2739 | |
2740 | @cindex empty expressions | |
2741 | @cindex expressions, empty | |
47342e8f | 2742 | An empty expression has no value: it is just whitespace or null. |
93b45514 | 2743 | Wherever an absolute expression is required, you may omit the |
05a0e43b | 2744 | expression, and @code{@value{AS}} assumes a value of (absolute) 0. This |
93b45514 RP |
2745 | is compatible with other assemblers. |
2746 | ||
242d9c06 | 2747 | @node Integer Exprs |
93b45514 | 2748 | @section Integer Expressions |
66b818fb RP |
2749 | |
2750 | @cindex integer expressions | |
2751 | @cindex expressions, integer | |
47342e8f RP |
2752 | An @dfn{integer expression} is one or more @emph{arguments} delimited |
2753 | by @emph{operators}. | |
2754 | ||
7a4c8e5c | 2755 | @menu |
ba487f3a RP |
2756 | * Arguments:: Arguments |
2757 | * Operators:: Operators | |
2758 | * Prefix Ops:: Prefix Operators | |
2759 | * Infix Ops:: Infix Operators | |
7a4c8e5c RP |
2760 | @end menu |
2761 | ||
242d9c06 | 2762 | @node Arguments |
47342e8f | 2763 | @subsection Arguments |
93b45514 | 2764 | |
66b818fb RP |
2765 | @cindex expression arguments |
2766 | @cindex arguments in expressions | |
2767 | @cindex operands in expressions | |
2768 | @cindex arithmetic operands | |
47342e8f RP |
2769 | @dfn{Arguments} are symbols, numbers or subexpressions. In other |
2770 | contexts arguments are sometimes called ``arithmetic operands''. In | |
2771 | this manual, to avoid confusing them with the ``instruction operands'' of | |
2772 | the machine language, we use the term ``argument'' to refer to parts of | |
b50e59fe | 2773 | expressions only, reserving the word ``operand'' to refer only to machine |
d0281557 | 2774 | instruction operands. |
93b45514 | 2775 | |
24b1493d RP |
2776 | Symbols are evaluated to yield @{@var{section} @var{NNN}@} where |
2777 | @var{section} is one of text, data, bss, absolute, | |
d0281557 | 2778 | or undefined. @var{NNN} is a signed, 2's complement 32 bit |
93b45514 RP |
2779 | integer. |
2780 | ||
2781 | Numbers are usually integers. | |
2782 | ||
2783 | A number can be a flonum or bignum. In this case, you are warned | |
f009d0ab | 2784 | that only the low order 32 bits are used, and @code{@value{AS}} pretends |
93b45514 RP |
2785 | these 32 bits are an integer. You may write integer-manipulating |
2786 | instructions that act on exotic constants, compatible with other | |
2787 | assemblers. | |
2788 | ||
66b818fb | 2789 | @cindex subexpressions |
b50e59fe RP |
2790 | Subexpressions are a left parenthesis @samp{(} followed by an integer |
2791 | expression, followed by a right parenthesis @samp{)}; or a prefix | |
47342e8f | 2792 | operator followed by an argument. |
93b45514 | 2793 | |
242d9c06 | 2794 | @node Operators |
93b45514 | 2795 | @subsection Operators |
66b818fb RP |
2796 | |
2797 | @cindex operators, in expressions | |
2798 | @cindex arithmetic functions | |
2799 | @cindex functions, in expressions | |
b50e59fe RP |
2800 | @dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix |
2801 | operators are followed by an argument. Infix operators appear | |
47342e8f | 2802 | between their arguments. Operators may be preceded and/or followed by |
93b45514 RP |
2803 | whitespace. |
2804 | ||
242d9c06 | 2805 | @node Prefix Ops |
66b818fb RP |
2806 | @subsection Prefix Operator |
2807 | ||
2808 | @cindex prefix operators | |
f009d0ab | 2809 | @code{@value{AS}} has the following @dfn{prefix operators}. They each take |
47342e8f | 2810 | one argument, which must be absolute. |
d0281557 RP |
2811 | |
2812 | @c the tex/end tex stuff surrounding this small table is meant to make | |
2813 | @c it align, on the printed page, with the similar table in the next | |
2814 | @c section (which is inside an enumerate). | |
2815 | @tex | |
2816 | \global\advance\leftskip by \itemindent | |
2817 | @end tex | |
2818 | ||
b50e59fe | 2819 | @table @code |
93b45514 | 2820 | @item - |
b50e59fe | 2821 | @dfn{Negation}. Two's complement negation. |
93b45514 | 2822 | @item ~ |
b50e59fe | 2823 | @dfn{Complementation}. Bitwise not. |
93b45514 RP |
2824 | @end table |
2825 | ||
d0281557 RP |
2826 | @tex |
2827 | \global\advance\leftskip by -\itemindent | |
2828 | @end tex | |
2829 | ||
242d9c06 | 2830 | @node Infix Ops |
b50e59fe | 2831 | @subsection Infix Operators |
47342e8f | 2832 | |
66b818fb RP |
2833 | @cindex infix operators |
2834 | @cindex operators, permitted arguments | |
b50e59fe RP |
2835 | @dfn{Infix operators} take two arguments, one on either side. Operators |
2836 | have precedence, but operations with equal precedence are performed left | |
2837 | to right. Apart from @code{+} or @code{-}, both arguments must be | |
2838 | absolute, and the result is absolute. | |
47342e8f | 2839 | |
93b45514 | 2840 | @enumerate |
66b818fb RP |
2841 | @cindex operator precedence |
2842 | @cindex precedence of operators | |
47342e8f | 2843 | |
93b45514 | 2844 | @item |
47342e8f | 2845 | Highest Precedence |
66b818fb | 2846 | |
93b45514 RP |
2847 | @table @code |
2848 | @item * | |
2849 | @dfn{Multiplication}. | |
66b818fb | 2850 | |
93b45514 RP |
2851 | @item / |
2852 | @dfn{Division}. Truncation is the same as the C operator @samp{/} | |
66b818fb | 2853 | |
93b45514 RP |
2854 | @item % |
2855 | @dfn{Remainder}. | |
66b818fb | 2856 | |
f009d0ab RP |
2857 | @item < |
2858 | @itemx << | |
2859 | @dfn{Shift Left}. Same as the C operator @samp{<<}. | |
66b818fb | 2860 | |
f009d0ab RP |
2861 | @item > |
2862 | @itemx >> | |
2863 | @dfn{Shift Right}. Same as the C operator @samp{>>}. | |
93b45514 | 2864 | @end table |
47342e8f | 2865 | |
93b45514 | 2866 | @item |
47342e8f | 2867 | Intermediate precedence |
66b818fb | 2868 | |
47342e8f | 2869 | @table @code |
93b45514 | 2870 | @item | |
66b818fb | 2871 | |
93b45514 | 2872 | @dfn{Bitwise Inclusive Or}. |
66b818fb | 2873 | |
93b45514 RP |
2874 | @item & |
2875 | @dfn{Bitwise And}. | |
66b818fb | 2876 | |
93b45514 RP |
2877 | @item ^ |
2878 | @dfn{Bitwise Exclusive Or}. | |
66b818fb | 2879 | |
93b45514 RP |
2880 | @item ! |
2881 | @dfn{Bitwise Or Not}. | |
2882 | @end table | |
47342e8f | 2883 | |
93b45514 | 2884 | @item |
47342e8f | 2885 | Lowest Precedence |
66b818fb | 2886 | |
47342e8f | 2887 | @table @code |
66b818fb RP |
2888 | @cindex addition, permitted arguments |
2889 | @cindex plus, permitted arguments | |
2890 | @cindex arguments for addition | |
71dd3c40 | 2891 | @item + |
dd565f85 RP |
2892 | @dfn{Addition}. If either argument is absolute, the result has the section of |
2893 | the other argument. You may not add together arguments from different | |
2894 | sections. | |
66b818fb | 2895 | |
66b818fb RP |
2896 | @cindex subtraction, permitted arguments |
2897 | @cindex minus, permitted arguments | |
2898 | @cindex arguments for subtraction | |
71dd3c40 | 2899 | @item - |
47342e8f | 2900 | @dfn{Subtraction}. If the right argument is absolute, the |
24b1493d | 2901 | result has the section of the left argument. |
dd565f85 RP |
2902 | If both arguments are in the same section, the result is absolute. |
2903 | You may not subtract arguments from different sections. | |
2904 | @c FIXME is there still something useful to say about undefined - undefined ? | |
93b45514 RP |
2905 | @end table |
2906 | @end enumerate | |
2907 | ||
dd565f85 RP |
2908 | In short, it's only meaningful to add or subtract the @emph{offsets} in an |
2909 | address; you can only have a defined section in one of the two arguments. | |
47342e8f | 2910 | |
242d9c06 | 2911 | @node Pseudo Ops |
93b45514 | 2912 | @chapter Assembler Directives |
d0281557 | 2913 | |
66b818fb RP |
2914 | @cindex directives, machine independent |
2915 | @cindex pseudo-ops, machine independent | |
2916 | @cindex machine independent directives | |
d0281557 | 2917 | All assembler directives have names that begin with a period (@samp{.}). |
66b818fb | 2918 | The rest of the name is letters, usually in lower case. |
d0281557 | 2919 | |
f009d0ab | 2920 | This chapter discusses directives that are available regardless of the |
8babef85 | 2921 | target machine configuration for the @sc{gnu} assembler. |
f009d0ab RP |
2922 | @ifset GENERIC |
2923 | Some machine configurations provide additional directives. | |
2924 | @xref{Machine Dependencies}. | |
2925 | @end ifset | |
2926 | @ifclear GENERIC | |
2927 | @ifset machine-directives | |
2928 | @xref{Machine Dependencies} for additional directives. | |
2929 | @end ifset | |
2930 | @end ifclear | |
d0281557 | 2931 | |
7a4c8e5c | 2932 | @menu |
ba487f3a | 2933 | * Abort:: @code{.abort} |
f009d0ab RP |
2934 | @ifset COFF |
2935 | * ABORT:: @code{.ABORT} | |
2936 | @end ifset | |
2937 | ||
ba487f3a | 2938 | * Align:: @code{.align @var{abs-expr} , @var{abs-expr}} |
2d8e0f62 | 2939 | * App-File:: @code{.app-file @var{string}} |
ba487f3a RP |
2940 | * Ascii:: @code{.ascii "@var{string}"}@dots{} |
2941 | * Asciz:: @code{.asciz "@var{string}"}@dots{} | |
931a8fab | 2942 | * Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}} |
ba487f3a RP |
2943 | * Byte:: @code{.byte @var{expressions}} |
2944 | * Comm:: @code{.comm @var{symbol} , @var{length} } | |
2945 | * Data:: @code{.data @var{subsection}} | |
f009d0ab | 2946 | @ifset COFF |
ba487f3a | 2947 | * Def:: @code{.def @var{name}} |
f009d0ab RP |
2948 | @end ifset |
2949 | @ifset aout-bout | |
ba487f3a | 2950 | * Desc:: @code{.desc @var{symbol}, @var{abs-expression}} |
f009d0ab RP |
2951 | @end ifset |
2952 | @ifset COFF | |
ba487f3a | 2953 | * Dim:: @code{.dim} |
f009d0ab RP |
2954 | @end ifset |
2955 | ||
ba487f3a RP |
2956 | * Double:: @code{.double @var{flonums}} |
2957 | * Eject:: @code{.eject} | |
2958 | * Else:: @code{.else} | |
f009d0ab | 2959 | @ifset COFF |
ba487f3a | 2960 | * Endef:: @code{.endef} |
f009d0ab RP |
2961 | @end ifset |
2962 | ||
ba487f3a RP |
2963 | * Endif:: @code{.endif} |
2964 | * Equ:: @code{.equ @var{symbol}, @var{expression}} | |
35cfacf0 ILT |
2965 | * Equiv:: @code{.equiv @var{symbol}, @var{expression}} |
2966 | * Err:: @code{.err} | |
ba487f3a | 2967 | * Extern:: @code{.extern} |
f009d0ab | 2968 | @ifclear no-file-dir |
ba487f3a | 2969 | * File:: @code{.file @var{string}} |
f009d0ab RP |
2970 | @end ifclear |
2971 | ||
ba487f3a RP |
2972 | * Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}} |
2973 | * Float:: @code{.float @var{flonums}} | |
2974 | * Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}} | |
2975 | * hword:: @code{.hword @var{expressions}} | |
2976 | * Ident:: @code{.ident} | |
2977 | * If:: @code{.if @var{absolute expression}} | |
2978 | * Include:: @code{.include "@var{file}"} | |
2979 | * Int:: @code{.int @var{expressions}} | |
95074dc3 ILT |
2980 | * Irp:: @code{.irp @var{symbol},@var{values}}@dots{} |
2981 | * Irpc:: @code{.irpc @var{symbol},@var{values}}@dots{} | |
ba487f3a | 2982 | * Lcomm:: @code{.lcomm @var{symbol} , @var{length}} |
66b818fb | 2983 | * Lflags:: @code{.lflags} |
f009d0ab | 2984 | @ifclear no-line-dir |
ba487f3a | 2985 | * Line:: @code{.line @var{line-number}} |
f009d0ab RP |
2986 | @end ifclear |
2987 | ||
ba487f3a | 2988 | * Ln:: @code{.ln @var{line-number}} |
910d7df2 | 2989 | * Linkonce:: @code{.linkonce [@var{type}]} |
ba487f3a RP |
2990 | * List:: @code{.list} |
2991 | * Long:: @code{.long @var{expressions}} | |
f009d0ab | 2992 | @ignore |
ba487f3a | 2993 | * Lsym:: @code{.lsym @var{symbol}, @var{expression}} |
f009d0ab RP |
2994 | @end ignore |
2995 | ||
95074dc3 | 2996 | * Macro:: @code{.macro @var{name} @var{args}}@dots{} |
910d7df2 | 2997 | * MRI:: @code{.mri @var{val}} |
95074dc3 | 2998 | |
ba487f3a RP |
2999 | * Nolist:: @code{.nolist} |
3000 | * Octa:: @code{.octa @var{bignums}} | |
3001 | * Org:: @code{.org @var{new-lc} , @var{fill}} | |
931a8fab | 3002 | * P2align:: @code{.p2align @var{abs-expr} , @var{abs-expr}} |
66b818fb | 3003 | * Psize:: @code{.psize @var{lines}, @var{columns}} |
ba487f3a | 3004 | * Quad:: @code{.quad @var{bignums}} |
95074dc3 | 3005 | * Rept:: @code{.rept @var{count}} |
ba487f3a | 3006 | * Sbttl:: @code{.sbttl "@var{subheading}"} |
f009d0ab | 3007 | @ifset COFF |
ba487f3a | 3008 | * Scl:: @code{.scl @var{class}} |
66b818fb | 3009 | * Section:: @code{.section @var{name}, @var{subsection}} |
f009d0ab RP |
3010 | @end ifset |
3011 | ||
ba487f3a RP |
3012 | * Set:: @code{.set @var{symbol}, @var{expression}} |
3013 | * Short:: @code{.short @var{expressions}} | |
3014 | * Single:: @code{.single @var{flonums}} | |
f009d0ab | 3015 | @ifset COFF |
ba487f3a | 3016 | * Size:: @code{.size} |
f009d0ab RP |
3017 | @end ifset |
3018 | ||
910d7df2 | 3019 | * Skip:: @code{.skip @var{size} , @var{fill}} |
3ffb03b1 | 3020 | * Sleb128:: @code{.sleb128 @var{expressions}} |
ba487f3a | 3021 | * Space:: @code{.space @var{size} , @var{fill}} |
f009d0ab | 3022 | @ifset have-stabs |
ba487f3a | 3023 | * Stab:: @code{.stabd, .stabn, .stabs} |
f009d0ab | 3024 | @end ifset |
e680d737 RP |
3025 | |
3026 | * String:: @code{.string "@var{str}"} | |
35cfacf0 ILT |
3027 | @ifset ELF |
3028 | * Symver:: @code{.symver @var{name},@var{name2@@nodename}} | |
3029 | @end ifset | |
f009d0ab | 3030 | @ifset COFF |
ba487f3a | 3031 | * Tag:: @code{.tag @var{structname}} |
f009d0ab RP |
3032 | @end ifset |
3033 | ||
ba487f3a RP |
3034 | * Text:: @code{.text @var{subsection}} |
3035 | * Title:: @code{.title "@var{heading}"} | |
f009d0ab | 3036 | @ifset COFF |
ba487f3a RP |
3037 | * Type:: @code{.type @var{int}} |
3038 | * Val:: @code{.val @var{addr}} | |
f009d0ab RP |
3039 | @end ifset |
3040 | ||
3ffb03b1 | 3041 | * Uleb128:: @code{.uleb128 @var{expressions}} |
ba487f3a RP |
3042 | * Word:: @code{.word @var{expressions}} |
3043 | * Deprecated:: Deprecated Directives | |
7a4c8e5c RP |
3044 | @end menu |
3045 | ||
242d9c06 | 3046 | @node Abort |
b50e59fe | 3047 | @section @code{.abort} |
66b818fb RP |
3048 | |
3049 | @cindex @code{abort} directive | |
3050 | @cindex stopping the assembly | |
93b45514 RP |
3051 | This directive stops the assembly immediately. It is for |
3052 | compatibility with other assemblers. The original idea was that the | |
d0281557 | 3053 | assembly language source would be piped into the assembler. If the sender |
f009d0ab | 3054 | of the source quit, it could use this directive tells @code{@value{AS}} to |
93b45514 RP |
3055 | quit also. One day @code{.abort} will not be supported. |
3056 | ||
f009d0ab RP |
3057 | @ifset COFF |
3058 | @node ABORT | |
d0281557 | 3059 | @section @code{.ABORT} |
66b818fb RP |
3060 | |
3061 | @cindex @code{ABORT} directive | |
f009d0ab | 3062 | When producing COFF output, @code{@value{AS}} accepts this directive as a |
d0281557 | 3063 | synonym for @samp{.abort}. |
66b818fb | 3064 | |
f009d0ab RP |
3065 | @ifset BOUT |
3066 | When producing @code{b.out} output, @code{@value{AS}} accepts this directive, | |
d0281557 | 3067 | but ignores it. |
f009d0ab RP |
3068 | @end ifset |
3069 | @end ifset | |
d0281557 | 3070 | |
242d9c06 | 3071 | @node Align |
c6c7035c | 3072 | @section @code{.align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}} |
66b818fb RP |
3073 | |
3074 | @cindex padding the location counter | |
66b818fb | 3075 | @cindex @code{align} directive |
c6c7035c MM |
3076 | Pad the location counter (in the current subsection) to a particular storage |
3077 | boundary. The first expression (which must be absolute) is the alignment | |
3078 | required, as described below. | |
3079 | ||
3080 | The second expression (also absolute) gives the fill value to be stored in the | |
3081 | padding bytes. It (and the comma) may be omitted. If it is omitted, the | |
3082 | padding bytes are normally zero. However, on some systems, if the section is | |
3083 | marked as containing code and the fill value is omitted, the space is filled | |
3084 | with no-op instructions. | |
3085 | ||
3086 | The third expression is also absolute, and is also optional. If it is present, | |
3087 | it is the maximum number of bytes that should be skipped by this alignment | |
3088 | directive. If doing the alignment would require skipping more bytes than the | |
3089 | specified maximum, then the alignment is not done at all. You can omit the | |
3090 | fill value (the second argument) entirely by simply using two commas after the | |
3091 | required alignment; this can be useful if you want the alignment to be filled | |
3092 | with no-op instructions when appropriate. | |
93b45514 | 3093 | |
931a8fab | 3094 | The way the required alignment is specified varies from system to system. |
910d7df2 | 3095 | For the a29k, hppa, m68k, m88k, w65, sparc, and Hitachi SH, and i386 using ELF |
71dd3c40 | 3096 | format, |
931a8fab | 3097 | the first expression is the |
05a0e43b | 3098 | alignment request in bytes. For example @samp{.align 8} advances |
9dcf8057 JL |
3099 | the location counter until it is a multiple of 8. If the location counter |
3100 | is already a multiple of 8, no change is needed. | |
9dcf8057 | 3101 | |
931a8fab KR |
3102 | For other systems, including the i386 using a.out format, it is the |
3103 | number of low-order zero bits the location counter must have after | |
3104 | advancement. For example @samp{.align 3} advances the location | |
3105 | counter until it a multiple of 8. If the location counter is already a | |
3106 | multiple of 8, no change is needed. | |
3107 | ||
3108 | This inconsistency is due to the different behaviors of the various | |
3109 | native assemblers for these systems which GAS must emulate. | |
3110 | GAS also provides @code{.balign} and @code{.p2align} directives, | |
3111 | described later, which have a consistent behavior across all | |
3112 | architectures (but are specific to GAS). | |
93b45514 | 3113 | |
2d8e0f62 RP |
3114 | @node App-File |
3115 | @section @code{.app-file @var{string}} | |
66b818fb RP |
3116 | |
3117 | @cindex logical file name | |
3118 | @cindex file name, logical | |
2d8e0f62 RP |
3119 | @cindex @code{app-file} directive |
3120 | @code{.app-file} | |
f009d0ab | 3121 | @ifclear no-file-dir |
d0281557 | 3122 | (which may also be spelled @samp{.file}) |
f009d0ab RP |
3123 | @end ifclear |
3124 | tells @code{@value{AS}} that we are about to start a new | |
d0281557 RP |
3125 | logical file. @var{string} is the new file name. In general, the |
3126 | filename is recognized whether or not it is surrounded by quotes @samp{"}; | |
b50e59fe RP |
3127 | but if you wish to specify an empty file name is permitted, |
3128 | you must give the quotes--@code{""}. This statement may go away in | |
f009d0ab | 3129 | future: it is only recognized to be compatible with old @code{@value{AS}} |
d0281557 | 3130 | programs.@refill |
b50e59fe | 3131 | |
242d9c06 | 3132 | @node Ascii |
b50e59fe | 3133 | @section @code{.ascii "@var{string}"}@dots{} |
66b818fb RP |
3134 | |
3135 | @cindex @code{ascii} directive | |
3136 | @cindex string literals | |
47342e8f | 3137 | @code{.ascii} expects zero or more string literals (@pxref{Strings}) |
93b45514 RP |
3138 | separated by commas. It assembles each string (with no automatic |
3139 | trailing zero byte) into consecutive addresses. | |
3140 | ||
242d9c06 | 3141 | @node Asciz |
b50e59fe | 3142 | @section @code{.asciz "@var{string}"}@dots{} |
66b818fb RP |
3143 | |
3144 | @cindex @code{asciz} directive | |
3145 | @cindex zero-terminated strings | |
3146 | @cindex null-terminated strings | |
b50e59fe RP |
3147 | @code{.asciz} is just like @code{.ascii}, but each string is followed by |
3148 | a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''. | |
93b45514 | 3149 | |
931a8fab | 3150 | @node Balign |
c6c7035c | 3151 | @section @code{.balign[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}} |
931a8fab KR |
3152 | |
3153 | @cindex padding the location counter given number of bytes | |
3154 | @cindex @code{balign} directive | |
3155 | Pad the location counter (in the current subsection) to a particular | |
3156 | storage boundary. The first expression (which must be absolute) is the | |
3157 | alignment request in bytes. For example @samp{.balign 8} advances | |
3158 | the location counter until it is a multiple of 8. If the location counter | |
3159 | is already a multiple of 8, no change is needed. | |
3160 | ||
c6c7035c MM |
3161 | The second expression (also absolute) gives the fill value to be stored in the |
3162 | padding bytes. It (and the comma) may be omitted. If it is omitted, the | |
3163 | padding bytes are normally zero. However, on some systems, if the section is | |
3164 | marked as containing code and the fill value is omitted, the space is filled | |
3165 | with no-op instructions. | |
3166 | ||
3167 | The third expression is also absolute, and is also optional. If it is present, | |
3168 | it is the maximum number of bytes that should be skipped by this alignment | |
3169 | directive. If doing the alignment would require skipping more bytes than the | |
3170 | specified maximum, then the alignment is not done at all. You can omit the | |
3171 | fill value (the second argument) entirely by simply using two commas after the | |
3172 | required alignment; this can be useful if you want the alignment to be filled | |
3173 | with no-op instructions when appropriate. | |
931a8fab | 3174 | |
71dd3c40 ILT |
3175 | @cindex @code{balignw} directive |
3176 | @cindex @code{balignl} directive | |
3177 | The @code{.balignw} and @code{.balignl} directives are variants of the | |
3178 | @code{.balign} directive. The @code{.balignw} directive treats the fill | |
3179 | pattern as a two byte word value. The @code{.balignl} directives treats the | |
3180 | fill pattern as a four byte longword value. For example, @code{.balignw | |
3181 | 4,0x368d} will align to a multiple of 4. If it skips two bytes, they will be | |
3182 | filled in with the value 0x368d (the exact placement of the bytes depends upon | |
3183 | the endianness of the processor). If it skips 1 or 3 bytes, the fill value is | |
3184 | undefined. | |
3185 | ||
242d9c06 | 3186 | @node Byte |
b50e59fe | 3187 | @section @code{.byte @var{expressions}} |
93b45514 | 3188 | |
66b818fb RP |
3189 | @cindex @code{byte} directive |
3190 | @cindex integers, one byte | |
47342e8f | 3191 | @code{.byte} expects zero or more expressions, separated by commas. |
93b45514 RP |
3192 | Each expression is assembled into the next byte. |
3193 | ||
242d9c06 | 3194 | @node Comm |
b50e59fe | 3195 | @section @code{.comm @var{symbol} , @var{length} } |
66b818fb RP |
3196 | |
3197 | @cindex @code{comm} directive | |
3198 | @cindex symbol, common | |
35cfacf0 ILT |
3199 | @code{.comm} declares a common symbol named @var{symbol}. When linking, a |
3200 | common symbol in one object file may be merged with a defined or common symbol | |
3201 | of the same name in another object file. If @code{@value{LD}} does not see a | |
3202 | definition for the symbol--just one or more common symbols--then it will | |
3203 | allocate @var{length} bytes of uninitialized memory. @var{length} must be an | |
3204 | absolute expression. If @code{@value{LD}} sees multiple common symbols with | |
3205 | the same name, and they do not all have the same size, it will allocate space | |
3206 | using the largest size. | |
3207 | ||
3208 | @ifset ELF | |
3209 | When using ELF, the @code{.comm} directive takes an optional third argument. | |
3210 | This is the desired alignment of the symbol, specified as a byte boundary (for | |
3211 | example, an alignment of 16 means that the least significant 4 bits of the | |
3212 | address should be zero). The alignment must be an absolute expression, and it | |
3213 | must be a power of two. If @code{@value{LD}} allocates uninitialized memory | |
3214 | for the common symbol, it will use the alignment when placing the symbol. If | |
3215 | no alignment is specified, @code{@value{AS}} will set the alignment to the | |
3216 | largest power of two less than or equal to the size of the symbol, up to a | |
3217 | maximum of 16. | |
3218 | @end ifset | |
47342e8f | 3219 | |
9dcf8057 JL |
3220 | @ifset HPPA |
3221 | The syntax for @code{.comm} differs slightly on the HPPA. The syntax is | |
509d5555 | 3222 | @samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional. |
9dcf8057 JL |
3223 | @end ifset |
3224 | ||
242d9c06 | 3225 | @node Data |
24b1493d | 3226 | @section @code{.data @var{subsection}} |
66b818fb RP |
3227 | |
3228 | @cindex @code{data} directive | |
f009d0ab | 3229 | @code{.data} tells @code{@value{AS}} to assemble the following statements onto the |
24b1493d RP |
3230 | end of the data subsection numbered @var{subsection} (which is an |
3231 | absolute expression). If @var{subsection} is omitted, it defaults | |
93b45514 RP |
3232 | to zero. |
3233 | ||
f009d0ab | 3234 | @ifset COFF |
242d9c06 | 3235 | @node Def |
d0281557 | 3236 | @section @code{.def @var{name}} |
66b818fb RP |
3237 | |
3238 | @cindex @code{def} directive | |
3239 | @cindex COFF symbols, debugging | |
3240 | @cindex debugging COFF symbols | |
d0281557 RP |
3241 | Begin defining debugging information for a symbol @var{name}; the |
3242 | definition extends until the @code{.endef} directive is encountered. | |
f009d0ab | 3243 | @ifset BOUT |
d0281557 | 3244 | |
f009d0ab | 3245 | This directive is only observed when @code{@value{AS}} is configured for COFF |
d0281557 RP |
3246 | format output; when producing @code{b.out}, @samp{.def} is recognized, |
3247 | but ignored. | |
f009d0ab RP |
3248 | @end ifset |
3249 | @end ifset | |
d0281557 | 3250 | |
f009d0ab | 3251 | @ifset aout-bout |
242d9c06 | 3252 | @node Desc |
f4335d56 | 3253 | @section @code{.desc @var{symbol}, @var{abs-expression}} |
66b818fb RP |
3254 | |
3255 | @cindex @code{desc} directive | |
3256 | @cindex COFF symbol descriptor | |
3257 | @cindex symbol descriptor, COFF | |
b50e59fe | 3258 | This directive sets the descriptor of the symbol (@pxref{Symbol Attributes}) |
f4335d56 | 3259 | to the low 16 bits of an absolute expression. |
93b45514 | 3260 | |
f009d0ab RP |
3261 | @ifset COFF |
3262 | The @samp{.desc} directive is not available when @code{@value{AS}} is | |
d0281557 | 3263 | configured for COFF output; it is only for @code{a.out} or @code{b.out} |
05a0e43b RP |
3264 | object format. For the sake of compatibility, @code{@value{AS}} accepts |
3265 | it, but produces no output, when configured for COFF. | |
f009d0ab RP |
3266 | @end ifset |
3267 | @end ifset | |
d0281557 | 3268 | |
f009d0ab | 3269 | @ifset COFF |
242d9c06 | 3270 | @node Dim |
d0281557 | 3271 | @section @code{.dim} |
66b818fb RP |
3272 | |
3273 | @cindex @code{dim} directive | |
3274 | @cindex COFF auxiliary symbol information | |
3275 | @cindex auxiliary symbol information, COFF | |
d0281557 RP |
3276 | This directive is generated by compilers to include auxiliary debugging |
3277 | information in the symbol table. It is only permitted inside | |
3278 | @code{.def}/@code{.endef} pairs. | |
f009d0ab | 3279 | @ifset BOUT |
d0281557 RP |
3280 | |
3281 | @samp{.dim} is only meaningful when generating COFF format output; when | |
f009d0ab | 3282 | @code{@value{AS}} is generating @code{b.out}, it accepts this directive but |
d0281557 | 3283 | ignores it. |
f009d0ab RP |
3284 | @end ifset |
3285 | @end ifset | |
d0281557 | 3286 | |
242d9c06 | 3287 | @node Double |
b50e59fe | 3288 | @section @code{.double @var{flonums}} |
66b818fb RP |
3289 | |
3290 | @cindex @code{double} directive | |
3291 | @cindex floating point numbers (double) | |
d0281557 RP |
3292 | @code{.double} expects zero or more flonums, separated by commas. It |
3293 | assembles floating point numbers. | |
f009d0ab | 3294 | @ifset GENERIC |
09352a5d | 3295 | The exact kind of floating point numbers emitted depends on how |
f009d0ab RP |
3296 | @code{@value{AS}} is configured. @xref{Machine Dependencies}. |
3297 | @end ifset | |
3298 | @ifclear GENERIC | |
3299 | @ifset IEEEFLOAT | |
3300 | On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers | |
66b818fb | 3301 | in @sc{ieee} format. |
f009d0ab RP |
3302 | @end ifset |
3303 | @end ifclear | |
b50e59fe | 3304 | |
242d9c06 | 3305 | @node Eject |
66b818fb RP |
3306 | @section @code{.eject} |
3307 | ||
3308 | @cindex @code{eject} directive | |
3309 | @cindex new page, in listings | |
3310 | @cindex page, in listings | |
3311 | @cindex listing control: new page | |
3312 | Force a page break at this point, when generating assembly listings. | |
3313 | ||
242d9c06 | 3314 | @node Else |
b50e59fe | 3315 | @section @code{.else} |
66b818fb RP |
3316 | |
3317 | @cindex @code{else} directive | |
f009d0ab | 3318 | @code{.else} is part of the @code{@value{AS}} support for conditional |
7a4c8e5c RP |
3319 | assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section |
3320 | of code to be assembled if the condition for the preceding @code{.if} | |
3321 | was false. | |
b50e59fe | 3322 | |
f009d0ab | 3323 | @ignore |
7a4c8e5c | 3324 | @node End, Endef, Else, Pseudo Ops |
b50e59fe | 3325 | @section @code{.end} |
66b818fb RP |
3326 | |
3327 | @cindex @code{end} directive | |
b50e59fe RP |
3328 | This doesn't do anything---but isn't an s_ignore, so I suspect it's |
3329 | meant to do something eventually (which is why it isn't documented here | |
3330 | as "for compatibility with blah"). | |
f009d0ab | 3331 | @end ignore |
d0281557 | 3332 | |
f009d0ab | 3333 | @ifset COFF |
242d9c06 | 3334 | @node Endef |
d0281557 | 3335 | @section @code{.endef} |
66b818fb RP |
3336 | |
3337 | @cindex @code{endef} directive | |
d0281557 | 3338 | This directive flags the end of a symbol definition begun with |
f009d0ab RP |
3339 | @code{.def}. |
3340 | @ifset BOUT | |
d0281557 RP |
3341 | |
3342 | @samp{.endef} is only meaningful when generating COFF format output; if | |
f009d0ab | 3343 | @code{@value{AS}} is configured to generate @code{b.out}, it accepts this |
d0281557 | 3344 | directive but ignores it. |
f009d0ab RP |
3345 | @end ifset |
3346 | @end ifset | |
7a4c8e5c | 3347 | |
242d9c06 | 3348 | @node Endif |
b50e59fe | 3349 | @section @code{.endif} |
66b818fb RP |
3350 | |
3351 | @cindex @code{endif} directive | |
f009d0ab | 3352 | @code{.endif} is part of the @code{@value{AS}} support for conditional assembly; |
b50e59fe | 3353 | it marks the end of a block of code that is only assembled |
7a4c8e5c | 3354 | conditionally. @xref{If,,@code{.if}}. |
b50e59fe | 3355 | |
242d9c06 | 3356 | @node Equ |
b50e59fe RP |
3357 | @section @code{.equ @var{symbol}, @var{expression}} |
3358 | ||
66b818fb RP |
3359 | @cindex @code{equ} directive |
3360 | @cindex assigning values to symbols | |
3361 | @cindex symbols, assigning values to | |
d0281557 | 3362 | This directive sets the value of @var{symbol} to @var{expression}. |
7a4c8e5c RP |
3363 | It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}. |
3364 | ||
9dcf8057 JL |
3365 | @ifset HPPA |
3366 | The syntax for @code{equ} on the HPPA is | |
509d5555 | 3367 | @samp{@var{symbol} .equ @var{expression}}. |
9dcf8057 JL |
3368 | @end ifset |
3369 | ||
35cfacf0 ILT |
3370 | @node Equiv |
3371 | @section @code{.equiv @var{symbol}, @var{expression}} | |
3372 | @cindex @code{equiv} directive | |
3373 | The @code{.equiv} directive is like @code{.equ} and @code{.set}, except that | |
3374 | the assembler will signal an error if @var{symbol} is already defined. | |
3375 | ||
3376 | Except for the contents of the error message, this is roughly equivalent to | |
3377 | @smallexample | |
3378 | .ifdef SYM | |
3379 | .err | |
3380 | .endif | |
3381 | .equ SYM,VAL | |
3382 | @end smallexample | |
3383 | ||
3384 | @node Err | |
3385 | @section @code{.err} | |
3386 | @cindex @code{err} directive | |
3387 | If @code{@value{AS}} assembles a @code{.err} directive, it will print an error | |
3388 | message and, unless the @code{-Z} option was used, it will not generate an | |
3389 | object file. This can be used to signal error an conditionally compiled code. | |
3390 | ||
242d9c06 | 3391 | @node Extern |
b50e59fe | 3392 | @section @code{.extern} |
66b818fb RP |
3393 | |
3394 | @cindex @code{extern} directive | |
b50e59fe | 3395 | @code{.extern} is accepted in the source program---for compatibility |
f009d0ab | 3396 | with other assemblers---but it is ignored. @code{@value{AS}} treats |
b50e59fe RP |
3397 | all undefined symbols as external. |
3398 | ||
f009d0ab | 3399 | @ifclear no-file-dir |
242d9c06 | 3400 | @node File |
66b818fb RP |
3401 | @section @code{.file @var{string}} |
3402 | ||
3403 | @cindex @code{file} directive | |
3404 | @cindex logical file name | |
3405 | @cindex file name, logical | |
2d8e0f62 | 3406 | @code{.file} (which may also be spelled @samp{.app-file}) tells |
f009d0ab | 3407 | @code{@value{AS}} that we are about to start a new logical file. |
d0281557 RP |
3408 | @var{string} is the new file name. In general, the filename is |
3409 | recognized whether or not it is surrounded by quotes @samp{"}; but if | |
3410 | you wish to specify an empty file name, you must give the | |
3411 | quotes--@code{""}. This statement may go away in future: it is only | |
f009d0ab RP |
3412 | recognized to be compatible with old @code{@value{AS}} programs. |
3413 | @ifset A29K | |
3414 | In some configurations of @code{@value{AS}}, @code{.file} has already been | |
3415 | removed to avoid conflicts with other assemblers. @xref{Machine Dependencies}. | |
3416 | @end ifset | |
3417 | @end ifclear | |
7a4c8e5c | 3418 | |
242d9c06 | 3419 | @node Fill |
b50e59fe | 3420 | @section @code{.fill @var{repeat} , @var{size} , @var{value}} |
66b818fb RP |
3421 | |
3422 | @cindex @code{fill} directive | |
3423 | @cindex writing patterns in memory | |
3424 | @cindex patterns, writing in memory | |
93b45514 RP |
3425 | @var{result}, @var{size} and @var{value} are absolute expressions. |
3426 | This emits @var{repeat} copies of @var{size} bytes. @var{Repeat} | |
3427 | may be zero or more. @var{Size} may be zero or more, but if it is | |
3428 | more than 8, then it is deemed to have the value 8, compatible with | |
3429 | other people's assemblers. The contents of each @var{repeat} bytes | |
3430 | is taken from an 8-byte number. The highest order 4 bytes are | |
3431 | zero. The lowest order 4 bytes are @var{value} rendered in the | |
f009d0ab | 3432 | byte-order of an integer on the computer @code{@value{AS}} is assembling for. |
93b45514 RP |
3433 | Each @var{size} bytes in a repetition is taken from the lowest order |
3434 | @var{size} bytes of this number. Again, this bizarre behavior is | |
3435 | compatible with other people's assemblers. | |
3436 | ||
d0281557 | 3437 | @var{size} and @var{value} are optional. |
93b45514 RP |
3438 | If the second comma and @var{value} are absent, @var{value} is |
3439 | assumed zero. If the first comma and following tokens are absent, | |
3440 | @var{size} is assumed to be 1. | |
3441 | ||
242d9c06 | 3442 | @node Float |
b50e59fe | 3443 | @section @code{.float @var{flonums}} |
66b818fb RP |
3444 | |
3445 | @cindex floating point numbers (single) | |
3446 | @cindex @code{float} directive | |
b50e59fe | 3447 | This directive assembles zero or more flonums, separated by commas. It |
d0281557 | 3448 | has the same effect as @code{.single}. |
f009d0ab | 3449 | @ifset GENERIC |
09352a5d | 3450 | The exact kind of floating point numbers emitted depends on how |
f009d0ab RP |
3451 | @code{@value{AS}} is configured. |
3452 | @xref{Machine Dependencies}. | |
3453 | @end ifset | |
3454 | @ifclear GENERIC | |
3455 | @ifset IEEEFLOAT | |
3456 | On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers | |
66b818fb | 3457 | in @sc{ieee} format. |
f009d0ab RP |
3458 | @end ifset |
3459 | @end ifclear | |
93b45514 | 3460 | |
242d9c06 | 3461 | @node Global |
b50e59fe | 3462 | @section @code{.global @var{symbol}}, @code{.globl @var{symbol}} |
66b818fb RP |
3463 | |
3464 | @cindex @code{global} directive | |
3465 | @cindex symbol, making visible to linker | |
f009d0ab | 3466 | @code{.global} makes the symbol visible to @code{@value{LD}}. If you define |
93b45514 RP |
3467 | @var{symbol} in your partial program, its value is made available to |
3468 | other partial programs that are linked with it. Otherwise, | |
05a0e43b RP |
3469 | @var{symbol} takes its attributes from a symbol of the same name |
3470 | from another file linked into the same program. | |
93b45514 | 3471 | |
b50e59fe RP |
3472 | Both spellings (@samp{.globl} and @samp{.global}) are accepted, for |
3473 | compatibility with other assemblers. | |
3474 | ||
9dcf8057 | 3475 | @ifset HPPA |
e680d737 RP |
3476 | On the HPPA, @code{.global} is not always enough to make it accessible to other |
3477 | partial programs. You may need the HPPA-only @code{.EXPORT} directive as well. | |
3478 | @xref{HPPA Directives,, HPPA Assembler Directives}. | |
9dcf8057 JL |
3479 | @end ifset |
3480 | ||
242d9c06 | 3481 | @node hword |
d0281557 | 3482 | @section @code{.hword @var{expressions}} |
66b818fb RP |
3483 | |
3484 | @cindex @code{hword} directive | |
3485 | @cindex integers, 16-bit | |
3486 | @cindex numbers, 16-bit | |
3487 | @cindex sixteen bit integers | |
d0281557 RP |
3488 | This expects zero or more @var{expressions}, and emits |
3489 | a 16 bit number for each. | |
3490 | ||
f009d0ab | 3491 | @ifset GENERIC |
d0281557 RP |
3492 | This directive is a synonym for @samp{.short}; depending on the target |
3493 | architecture, it may also be a synonym for @samp{.word}. | |
f009d0ab RP |
3494 | @end ifset |
3495 | @ifclear GENERIC | |
3496 | @ifset W32 | |
d0281557 | 3497 | This directive is a synonym for @samp{.short}. |
f009d0ab RP |
3498 | @end ifset |
3499 | @ifset W16 | |
24b1493d | 3500 | This directive is a synonym for both @samp{.short} and @samp{.word}. |
f009d0ab RP |
3501 | @end ifset |
3502 | @end ifclear | |
d0281557 | 3503 | |
242d9c06 | 3504 | @node Ident |
b50e59fe | 3505 | @section @code{.ident} |
66b818fb RP |
3506 | |
3507 | @cindex @code{ident} directive | |
b50e59fe | 3508 | This directive is used by some assemblers to place tags in object files. |
f009d0ab | 3509 | @code{@value{AS}} simply accepts the directive for source-file |
b50e59fe RP |
3510 | compatibility with such assemblers, but does not actually emit anything |
3511 | for it. | |
3512 | ||
242d9c06 | 3513 | @node If |
b50e59fe | 3514 | @section @code{.if @var{absolute expression}} |
66b818fb RP |
3515 | |
3516 | @cindex conditional assembly | |
3517 | @cindex @code{if} directive | |
b50e59fe RP |
3518 | @code{.if} marks the beginning of a section of code which is only |
3519 | considered part of the source program being assembled if the argument | |
3520 | (which must be an @var{absolute expression}) is non-zero. The end of | |
3521 | the conditional section of code must be marked by @code{.endif} | |
7a4c8e5c | 3522 | (@pxref{Endif,,@code{.endif}}); optionally, you may include code for the |
910d7df2 | 3523 | alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}). |
b50e59fe RP |
3524 | |
3525 | The following variants of @code{.if} are also supported: | |
3526 | @table @code | |
66b818fb | 3527 | @cindex @code{ifdef} directive |
71dd3c40 | 3528 | @item .ifdef @var{symbol} |
b50e59fe RP |
3529 | Assembles the following section of code if the specified @var{symbol} |
3530 | has been defined. | |
3531 | ||
f009d0ab | 3532 | @ignore |
66b818fb | 3533 | @cindex @code{ifeqs} directive |
71dd3c40 | 3534 | @item .ifeqs |
d0281557 | 3535 | Not yet implemented. |
f009d0ab | 3536 | @end ignore |
b50e59fe | 3537 | |
66b818fb RP |
3538 | @cindex @code{ifndef} directive |
3539 | @cindex @code{ifnotdef} directive | |
71dd3c40 | 3540 | @item .ifndef @var{symbol} |
910d7df2 | 3541 | @itemx .ifnotdef @var{symbol} |
b50e59fe RP |
3542 | Assembles the following section of code if the specified @var{symbol} |
3543 | has not been defined. Both spelling variants are equivalent. | |
93b45514 | 3544 | |
f009d0ab | 3545 | @ignore |
b50e59fe | 3546 | @item ifnes |
d0281557 | 3547 | Not yet implemented. |
f009d0ab | 3548 | @end ignore |
b50e59fe RP |
3549 | @end table |
3550 | ||
242d9c06 | 3551 | @node Include |
b50e59fe | 3552 | @section @code{.include "@var{file}"} |
66b818fb RP |
3553 | |
3554 | @cindex @code{include} directive | |
3555 | @cindex supporting files, including | |
3556 | @cindex files, including | |
b50e59fe RP |
3557 | This directive provides a way to include supporting files at specified |
3558 | points in your source program. The code from @var{file} is assembled as | |
3559 | if it followed the point of the @code{.include}; when the end of the | |
3560 | included file is reached, assembly of the original file continues. You | |
3561 | can control the search paths used with the @samp{-I} command-line option | |
7a4c8e5c RP |
3562 | (@pxref{Invoking,,Command-Line Options}). Quotation marks are required |
3563 | around @var{file}. | |
b50e59fe | 3564 | |
242d9c06 | 3565 | @node Int |
b50e59fe | 3566 | @section @code{.int @var{expressions}} |
66b818fb RP |
3567 | |
3568 | @cindex @code{int} directive | |
f009d0ab | 3569 | @cindex integers, 32-bit |
05a0e43b RP |
3570 | Expect zero or more @var{expressions}, of any section, separated by commas. |
3571 | For each expression, emit a number that, at run time, is the value of that | |
3572 | expression. The byte order and bit size of the number depends on what kind | |
3573 | of target the assembly is for. | |
f009d0ab RP |
3574 | |
3575 | @ifclear GENERIC | |
3576 | @ifset H8 | |
8d8ddccb RP |
3577 | On the H8/500 and most forms of the H8/300, @code{.int} emits 16-bit |
3578 | integers. On the H8/300H and the Hitachi SH, however, @code{.int} emits | |
3579 | 32-bit integers. | |
f009d0ab RP |
3580 | @end ifset |
3581 | @end ifclear | |
93b45514 | 3582 | |
95074dc3 ILT |
3583 | @node Irp |
3584 | @section @code{.irp @var{symbol},@var{values}}@dots{} | |
3585 | ||
3586 | @cindex @code{irp} directive | |
3587 | Evaluate a sequence of statements assigning different values to @var{symbol}. | |
3588 | The sequence of statements starts at the @code{.irp} directive, and is | |
3589 | terminated by an @code{.endr} directive. For each @var{value}, @var{symbol} is | |
3590 | set to @var{value}, and the sequence of statements is assembled. If no | |
3591 | @var{value} is listed, the sequence of statements is assembled once, with | |
3592 | @var{symbol} set to the null string. To refer to @var{symbol} within the | |
3593 | sequence of statements, use @var{\symbol}. | |
3594 | ||
3595 | For example, assembling | |
3596 | ||
3597 | @example | |
3598 | .irp param,1,2,3 | |
3599 | move d\param,sp@@- | |
3600 | .endr | |
3601 | @end example | |
3602 | ||
3603 | is equivalent to assembling | |
3604 | ||
3605 | @example | |
3606 | move d1,sp@@- | |
3607 | move d2,sp@@- | |
3608 | move d3,sp@@- | |
3609 | @end example | |
3610 | ||
3611 | @node Irpc | |
3612 | @section @code{.irpc @var{symbol},@var{values}}@dots{} | |
3613 | ||
3614 | @cindex @code{irpc} directive | |
3615 | Evaluate a sequence of statements assigning different values to @var{symbol}. | |
3616 | The sequence of statements starts at the @code{.irpc} directive, and is | |
3617 | terminated by an @code{.endr} directive. For each character in @var{value}, | |
3618 | @var{symbol} is set to the character, and the sequence of statements is | |
3619 | assembled. If no @var{value} is listed, the sequence of statements is | |
3620 | assembled once, with @var{symbol} set to the null string. To refer to | |
3621 | @var{symbol} within the sequence of statements, use @var{\symbol}. | |
3622 | ||
3623 | For example, assembling | |
3624 | ||
3625 | @example | |
3626 | .irpc param,123 | |
3627 | move d\param,sp@@- | |
3628 | .endr | |
3629 | @end example | |
3630 | ||
3631 | is equivalent to assembling | |
3632 | ||
3633 | @example | |
3634 | move d1,sp@@- | |
3635 | move d2,sp@@- | |
3636 | move d3,sp@@- | |
3637 | @end example | |
3638 | ||
242d9c06 | 3639 | @node Lcomm |
b50e59fe | 3640 | @section @code{.lcomm @var{symbol} , @var{length}} |
66b818fb RP |
3641 | |
3642 | @cindex @code{lcomm} directive | |
3643 | @cindex local common symbols | |
3644 | @cindex symbols, local common | |
7a4c8e5c | 3645 | Reserve @var{length} (an absolute expression) bytes for a local common |
24b1493d | 3646 | denoted by @var{symbol}. The section and value of @var{symbol} are |
7a4c8e5c | 3647 | those of the new local common. The addresses are allocated in the bss |
05a0e43b | 3648 | section, so that at run-time the bytes start off zeroed. @var{Symbol} |
7a4c8e5c | 3649 | is not declared global (@pxref{Global,,@code{.global}}), so is normally |
f009d0ab | 3650 | not visible to @code{@value{LD}}. |
93b45514 | 3651 | |
35cfacf0 ILT |
3652 | @ifset GENERIC |
3653 | Some targets permit a third argument to be used with @code{.lcomm}. This | |
3654 | argument specifies the desired alignment of the symbol in the bss section. | |
3655 | @end ifset | |
3656 | ||
9dcf8057 JL |
3657 | @ifset HPPA |
3658 | The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is | |
509d5555 | 3659 | @samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional. |
9dcf8057 JL |
3660 | @end ifset |
3661 | ||
242d9c06 | 3662 | @node Lflags |
66b818fb RP |
3663 | @section @code{.lflags} |
3664 | ||
3665 | @cindex @code{lflags} directive (ignored) | |
f009d0ab | 3666 | @code{@value{AS}} accepts this directive, for compatibility with other |
66b818fb RP |
3667 | assemblers, but ignores it. |
3668 | ||
f009d0ab | 3669 | @ifclear no-line-dir |
242d9c06 | 3670 | @node Line |
d0281557 | 3671 | @section @code{.line @var{line-number}} |
66b818fb RP |
3672 | |
3673 | @cindex @code{line} directive | |
f009d0ab RP |
3674 | @end ifclear |
3675 | @ifset no-line-dir | |
242d9c06 | 3676 | @node Ln |
b50e59fe | 3677 | @section @code{.ln @var{line-number}} |
66b818fb RP |
3678 | |
3679 | @cindex @code{ln} directive | |
f009d0ab | 3680 | @end ifset |
66b818fb | 3681 | @cindex logical line number |
f009d0ab | 3682 | @ifset aout-bout |
05a0e43b RP |
3683 | Change the logical line number. @var{line-number} must be an absolute |
3684 | expression. The next line has that logical line number. Therefore any other | |
3685 | statements on the current line (after a statement separator character) are | |
3686 | reported as on logical line number @var{line-number} @minus{} 1. One day | |
3687 | @code{@value{AS}} will no longer support this directive: it is recognized only | |
f009d0ab | 3688 | for compatibility with existing assembler programs. |
7a4c8e5c | 3689 | |
f009d0ab RP |
3690 | @ifset GENERIC |
3691 | @ifset A29K | |
3692 | @emph{Warning:} In the AMD29K configuration of @value{AS}, this command is | |
65fbb2d7 | 3693 | not available; use the synonym @code{.ln} in that context. |
f009d0ab RP |
3694 | @end ifset |
3695 | @end ifset | |
3696 | @end ifset | |
d0281557 | 3697 | |
f009d0ab | 3698 | @ifclear no-line-dir |
d0281557 | 3699 | Even though this is a directive associated with the @code{a.out} or |
05a0e43b RP |
3700 | @code{b.out} object-code formats, @code{@value{AS}} still recognizes it |
3701 | when producing COFF output, and treats @samp{.line} as though it | |
d0281557 | 3702 | were the COFF @samp{.ln} @emph{if} it is found outside a |
f009d0ab | 3703 | @code{.def}/@code{.endef} pair. |
d0281557 RP |
3704 | |
3705 | Inside a @code{.def}, @samp{.line} is, instead, one of the directives | |
3706 | used by compilers to generate auxiliary symbol information for | |
3707 | debugging. | |
f009d0ab | 3708 | @end ifclear |
d0281557 | 3709 | |
910d7df2 C |
3710 | @node Linkonce |
3711 | @section @code{.linkonce [@var{type}]} | |
3712 | @cindex COMDAT | |
3713 | @cindex @code{linkonce} directive | |
3714 | @cindex common sections | |
3715 | Mark the current section so that the linker only includes a single copy of it. | |
3716 | This may be used to include the same section in several different object files, | |
3717 | but ensure that the linker will only include it once in the final output file. | |
3718 | The @code{.linkonce} pseudo-op must be used for each instance of the section. | |
3719 | Duplicate sections are detected based on the section name, so it should be | |
3720 | unique. | |
3721 | ||
3722 | This directive is only supported by a few object file formats; as of this | |
3723 | writing, the only object file format which supports it is the Portable | |
3724 | Executable format used on Windows NT. | |
3725 | ||
3726 | The @var{type} argument is optional. If specified, it must be one of the | |
3727 | following strings. For example: | |
3728 | @smallexample | |
3729 | .linkonce same_size | |
3730 | @end smallexample | |
3731 | Not all types may be supported on all object file formats. | |
3732 | ||
3733 | @table @code | |
3734 | @item discard | |
3735 | Silently discard duplicate sections. This is the default. | |
3736 | ||
3737 | @item one_only | |
3738 | Warn if there are duplicate sections, but still keep only one copy. | |
3739 | ||
3740 | @item same_size | |
3741 | Warn if any of the duplicates have different sizes. | |
3742 | ||
3743 | @item same_contents | |
3744 | Warn if any of the duplicates do not have exactly the same contents. | |
3745 | @end table | |
3746 | ||
242d9c06 | 3747 | @node Ln |
d0281557 | 3748 | @section @code{.ln @var{line-number}} |
66b818fb RP |
3749 | |
3750 | @cindex @code{ln} directive | |
f009d0ab | 3751 | @ifclear no-line-dir |
d0281557 | 3752 | @samp{.ln} is a synonym for @samp{.line}. |
f009d0ab RP |
3753 | @end ifclear |
3754 | @ifset no-line-dir | |
3755 | Tell @code{@value{AS}} to change the logical line number. @var{line-number} | |
05a0e43b | 3756 | must be an absolute expression. The next line has that logical |
7a4c8e5c | 3757 | line number, so any other statements on the current line (after a |
05a0e43b | 3758 | statement separator character @code{;}) are reported as on logical |
d0281557 | 3759 | line number @var{line-number} @minus{} 1. |
f009d0ab | 3760 | @ifset BOUT |
d0281557 | 3761 | |
f009d0ab RP |
3762 | This directive is accepted, but ignored, when @code{@value{AS}} is |
3763 | configured for @code{b.out}; its effect is only associated with COFF | |
3764 | output format. | |
3765 | @end ifset | |
3766 | @end ifset | |
d0281557 | 3767 | |
910d7df2 C |
3768 | @node MRI |
3769 | @section @code{.mri @var{val}} | |
3770 | ||
3771 | @cindex @code{mri} directive | |
3772 | @cindex MRI mode, temporarily | |
3773 | If @var{val} is non-zero, this tells @code{@value{AS}} to enter MRI mode. If | |
3774 | @var{val} is zero, this tells @code{@value{AS}} to exit MRI mode. This change | |
3775 | affects code assembled until the next @code{.mri} directive, or until the end | |
3776 | of the file. @xref{M, MRI mode, MRI mode}. | |
3777 | ||
242d9c06 | 3778 | @node List |
66b818fb RP |
3779 | @section @code{.list} |
3780 | ||
3781 | @cindex @code{list} directive | |
3782 | @cindex listing control, turning on | |
3783 | Control (in conjunction with the @code{.nolist} directive) whether or | |
3784 | not assembly listings are generated. These two directives maintain an | |
3785 | internal counter (which is zero initially). @code{.list} increments the | |
3786 | counter, and @code{.nolist} decrements it. Assembly listings are | |
3787 | generated whenever the counter is greater than zero. | |
3788 | ||
3789 | By default, listings are disabled. When you enable them (with the | |
3790 | @samp{-a} command line option; @pxref{Invoking,,Command-Line Options}), | |
3791 | the initial value of the listing counter is one. | |
b50e59fe | 3792 | |
242d9c06 | 3793 | @node Long |
b50e59fe | 3794 | @section @code{.long @var{expressions}} |
66b818fb RP |
3795 | |
3796 | @cindex @code{long} directive | |
7a4c8e5c | 3797 | @code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}. |
93b45514 | 3798 | |
242d9c06 SC |
3799 | @ignore |
3800 | @c no one seems to know what this is for or whether this description is | |
3801 | @c what it really ought to do | |
3802 | @node Lsym | |
b50e59fe | 3803 | @section @code{.lsym @var{symbol}, @var{expression}} |
66b818fb RP |
3804 | |
3805 | @cindex @code{lsym} directive | |
3806 | @cindex symbol, not referenced in assembly | |
47342e8f | 3807 | @code{.lsym} creates a new symbol named @var{symbol}, but does not put it in |
93b45514 RP |
3808 | the hash table, ensuring it cannot be referenced by name during the |
3809 | rest of the assembly. This sets the attributes of the symbol to be | |
47342e8f | 3810 | the same as the expression value: |
d0281557 | 3811 | @smallexample |
b50e59fe | 3812 | @var{other} = @var{descriptor} = 0 |
24b1493d | 3813 | @var{type} = @r{(section of @var{expression})} |
b50e59fe | 3814 | @var{value} = @var{expression} |
d0281557 RP |
3815 | @end smallexample |
3816 | @noindent | |
3817 | The new symbol is not flagged as external. | |
242d9c06 | 3818 | @end ignore |
93b45514 | 3819 | |
95074dc3 ILT |
3820 | @node Macro |
3821 | @section @code{.macro} | |
3822 | ||
3823 | @cindex macros | |
3824 | The commands @code{.macro} and @code{.endm} allow you to define macros that | |
3825 | generate assembly output. For example, this definition specifies a macro | |
3826 | @code{sum} that puts a sequence of numbers into memory: | |
3827 | ||
3828 | @example | |
3829 | .macro sum from=0, to=5 | |
3830 | .long \from | |
3831 | .if \to-\from | |
3832 | sum "(\from+1)",\to | |
3833 | .endif | |
3834 | .endm | |
3835 | @end example | |
3836 | ||
3837 | @noindent | |
3838 | With that definition, @samp{SUM 0,5} is equivalent to this assembly input: | |
3839 | ||
3840 | @example | |
3841 | .long 0 | |
3842 | .long 1 | |
3843 | .long 2 | |
3844 | .long 3 | |
3845 | .long 4 | |
3846 | .long 5 | |
3847 | @end example | |
3848 | ||
3849 | @ftable @code | |
3850 | @item .macro @var{macname} | |
3851 | @itemx .macro @var{macname} @var{macargs} @dots{} | |
3852 | @cindex @code{macro} directive | |
3853 | Begin the definition of a macro called @var{macname}. If your macro | |
3854 | definition requires arguments, specify their names after the macro name, | |
3855 | separated by commas or spaces. You can supply a default value for any | |
3856 | macro argument by following the name with @samp{=@var{deflt}}. For | |
3857 | example, these are all valid @code{.macro} statements: | |
3858 | ||
3859 | @table @code | |
3860 | @item .macro comm | |
3861 | Begin the definition of a macro called @code{comm}, which takes no | |
3862 | arguments. | |
3863 | ||
3864 | @item .macro plus1 p, p1 | |
3865 | @itemx .macro plus1 p p1 | |
3866 | Either statement begins the definition of a macro called @code{plus1}, | |
3867 | which takes two arguments; within the macro definition, write | |
3868 | @samp{\p} or @samp{\p1} to evaluate the arguments. | |
3869 | ||
3870 | @item .macro reserve_str p1=0 p2 | |
3871 | Begin the definition of a macro called @code{reserve_str}, with two | |
3872 | arguments. The first argument has a default value, but not the second. | |
3873 | After the definition is complete, you can call the macro either as | |
3874 | @samp{reserve_str @var{a},@var{b}} (with @samp{\p1} evaluating to | |
3875 | @var{a} and @samp{\p2} evaluating to @var{b}), or as @samp{reserve_str | |
3876 | ,@var{b}} (with @samp{\p1} evaluating as the default, in this case | |
3877 | @samp{0}, and @samp{\p2} evaluating to @var{b}). | |
3878 | @end table | |
3879 | ||
3880 | When you call a macro, you can specify the argument values either by | |
3881 | position, or by keyword. For example, @samp{sum 9,17} is equivalent to | |
3882 | @samp{sum to=17, from=9}. | |
3883 | ||
3884 | @item .endm | |
3885 | @cindex @code{endm} directive | |
3886 | Mark the end of a macro definition. | |
3887 | ||
3888 | @item .exitm | |
3889 | @cindex @code{exitm} directive | |
3890 | Exit early from the current macro definition. | |
3891 | ||
3892 | @cindex number of macros executed | |
3893 | @cindex macros, count executed | |
3894 | @item \@@ | |
3895 | @code{@value{AS}} maintains a counter of how many macros it has | |
3896 | executed in this pseudo-variable; you can copy that number to your | |
3897 | output with @samp{\@@}, but @emph{only within a macro definition}. | |
3898 | ||
3899 | @ignore | |
3900 | @item LOCAL @var{name} [ , @dots{} ] | |
3901 | @emph{Warning: @code{LOCAL} is only available if you select ``alternate | |
3902 | macro syntax'' with @samp{-a} or @samp{--alternate}.} @xref{Alternate,, | |
3903 | Alternate macro syntax}. | |
3904 | ||
3905 | Generate a string replacement for each of the @var{name} arguments, and | |
3906 | replace any instances of @var{name} in each macro expansion. The | |
3907 | replacement string is unique in the assembly, and different for each | |
3908 | separate macro expansion. @code{LOCAL} allows you to write macros that | |
3909 | define symbols, without fear of conflict between separate macro expansions. | |
3910 | @end ignore | |
3911 | @end ftable | |
3912 | ||
242d9c06 | 3913 | @node Nolist |
66b818fb RP |
3914 | @section @code{.nolist} |
3915 | ||
3916 | @cindex @code{nolist} directive | |
3917 | @cindex listing control, turning off | |
3918 | Control (in conjunction with the @code{.list} directive) whether or | |
3919 | not assembly listings are generated. These two directives maintain an | |
3920 | internal counter (which is zero initially). @code{.list} increments the | |
3921 | counter, and @code{.nolist} decrements it. Assembly listings are | |
3922 | generated whenever the counter is greater than zero. | |
3923 | ||
242d9c06 | 3924 | @node Octa |
b50e59fe | 3925 | @section @code{.octa @var{bignums}} |
66b818fb RP |
3926 | |
3927 | @c FIXME: double size emitted for "octa" on i960, others? Or warn? | |
3928 | @cindex @code{octa} directive | |
3929 | @cindex integer, 16-byte | |
3930 | @cindex sixteen byte integer | |
47342e8f | 3931 | This directive expects zero or more bignums, separated by commas. For each |
b50e59fe RP |
3932 | bignum, it emits a 16-byte integer. |
3933 | ||
d0281557 RP |
3934 | The term ``octa'' comes from contexts in which a ``word'' is two bytes; |
3935 | hence @emph{octa}-word for 16 bytes. | |
93b45514 | 3936 | |
242d9c06 | 3937 | @node Org |
b50e59fe | 3938 | @section @code{.org @var{new-lc} , @var{fill}} |
47342e8f | 3939 | |
66b818fb RP |
3940 | @cindex @code{org} directive |
3941 | @cindex location counter, advancing | |
3942 | @cindex advancing location counter | |
3943 | @cindex current address, advancing | |
05a0e43b | 3944 | Advance the location counter of the current section to |
93b45514 | 3945 | @var{new-lc}. @var{new-lc} is either an absolute expression or an |
24b1493d RP |
3946 | expression with the same section as the current subsection. That is, |
3947 | you can't use @code{.org} to cross sections: if @var{new-lc} has the | |
3948 | wrong section, the @code{.org} directive is ignored. To be compatible | |
3949 | with former assemblers, if the section of @var{new-lc} is absolute, | |
05a0e43b | 3950 | @code{@value{AS}} issues a warning, then pretends the section of @var{new-lc} |
24b1493d | 3951 | is the same as the current subsection. |
47342e8f RP |
3952 | |
3953 | @code{.org} may only increase the location counter, or leave it | |
3954 | unchanged; you cannot use @code{.org} to move the location counter | |
d0281557 | 3955 | backwards. |
47342e8f | 3956 | |
b50e59fe RP |
3957 | @c double negative used below "not undefined" because this is a specific |
3958 | @c reference to "undefined" (as SEG_UNKNOWN is called in this manual) | |
71dd3c40 | 3959 | @c section. doc@cygnus.com 18feb91 |
dd565f85 | 3960 | Because @code{@value{AS}} tries to assemble programs in one pass, @var{new-lc} |
b50e59fe | 3961 | may not be undefined. If you really detest this restriction we eagerly await |
d0281557 | 3962 | a chance to share your improved assembler. |
93b45514 | 3963 | |
24b1493d RP |
3964 | Beware that the origin is relative to the start of the section, not |
3965 | to the start of the subsection. This is compatible with other | |
93b45514 RP |
3966 | people's assemblers. |
3967 | ||
24b1493d | 3968 | When the location counter (of the current subsection) is advanced, the |
93b45514 RP |
3969 | intervening bytes are filled with @var{fill} which should be an |
3970 | absolute expression. If the comma and @var{fill} are omitted, | |
3971 | @var{fill} defaults to zero. | |
3972 | ||
931a8fab | 3973 | @node P2align |
c6c7035c | 3974 | @section @code{.p2align[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}} |
931a8fab KR |
3975 | |
3976 | @cindex padding the location counter given a power of two | |
3977 | @cindex @code{p2align} directive | |
3978 | Pad the location counter (in the current subsection) to a particular | |
3979 | storage boundary. The first expression (which must be absolute) is the | |
3980 | number of low-order zero bits the location counter must have after | |
3981 | advancement. For example @samp{.p2align 3} advances the location | |
3982 | counter until it a multiple of 8. If the location counter is already a | |
3983 | multiple of 8, no change is needed. | |
3984 | ||
c6c7035c MM |
3985 | The second expression (also absolute) gives the fill value to be stored in the |
3986 | padding bytes. It (and the comma) may be omitted. If it is omitted, the | |
3987 | padding bytes are normally zero. However, on some systems, if the section is | |
3988 | marked as containing code and the fill value is omitted, the space is filled | |
3989 | with no-op instructions. | |
3990 | ||
3991 | The third expression is also absolute, and is also optional. If it is present, | |
3992 | it is the maximum number of bytes that should be skipped by this alignment | |
3993 | directive. If doing the alignment would require skipping more bytes than the | |
3994 | specified maximum, then the alignment is not done at all. You can omit the | |
3995 | fill value (the second argument) entirely by simply using two commas after the | |
3996 | required alignment; this can be useful if you want the alignment to be filled | |
3997 | with no-op instructions when appropriate. | |
931a8fab | 3998 | |
71dd3c40 ILT |
3999 | @cindex @code{p2alignw} directive |
4000 | @cindex @code{p2alignl} directive | |
4001 | The @code{.p2alignw} and @code{.p2alignl} directives are variants of the | |
4002 | @code{.p2align} directive. The @code{.p2alignw} directive treats the fill | |
4003 | pattern as a two byte word value. The @code{.p2alignl} directives treats the | |
4004 | fill pattern as a four byte longword value. For example, @code{.p2alignw | |
4005 | 2,0x368d} will align to a multiple of 4. If it skips two bytes, they will be | |
4006 | filled in with the value 0x368d (the exact placement of the bytes depends upon | |
4007 | the endianness of the processor). If it skips 1 or 3 bytes, the fill value is | |
4008 | undefined. | |
4009 | ||
242d9c06 | 4010 | @node Psize |
66b818fb RP |
4011 | @section @code{.psize @var{lines} , @var{columns}} |
4012 | ||
4013 | @cindex @code{psize} directive | |
4014 | @cindex listing control: paper size | |
4015 | @cindex paper size, for listings | |
4016 | Use this directive to declare the number of lines---and, optionally, the | |
f009d0ab | 4017 | number of columns---to use for each page, when generating listings. |
66b818fb | 4018 | |
05a0e43b | 4019 | If you do not use @code{.psize}, listings use a default line-count |
66b818fb RP |
4020 | of 60. You may omit the comma and @var{columns} specification; the |
4021 | default width is 200 columns. | |
4022 | ||
05a0e43b | 4023 | @code{@value{AS}} generates formfeeds whenever the specified number of |
66b818fb | 4024 | lines is exceeded (or whenever you explicitly request one, using |
f009d0ab | 4025 | @code{.eject}). |
66b818fb RP |
4026 | |
4027 | If you specify @var{lines} as @code{0}, no formfeeds are generated save | |
4028 | those explicitly specified with @code{.eject}. | |
4029 | ||
242d9c06 | 4030 | @node Quad |
b50e59fe | 4031 | @section @code{.quad @var{bignums}} |
66b818fb RP |
4032 | |
4033 | @cindex @code{quad} directive | |
b50e59fe | 4034 | @code{.quad} expects zero or more bignums, separated by commas. For |
d0281557 | 4035 | each bignum, it emits |
f009d0ab RP |
4036 | @ifclear bignum-16 |
4037 | an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a | |
4038 | warning message; and just takes the lowest order 8 bytes of the bignum. | |
66b818fb RP |
4039 | @cindex eight-byte integer |
4040 | @cindex integer, 8-byte | |
b50e59fe | 4041 | |
d0281557 | 4042 | The term ``quad'' comes from contexts in which a ``word'' is two bytes; |
b50e59fe | 4043 | hence @emph{quad}-word for 8 bytes. |
f009d0ab RP |
4044 | @end ifclear |
4045 | @ifset bignum-16 | |
d0281557 | 4046 | a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a |
f009d0ab | 4047 | warning message; and just takes the lowest order 16 bytes of the bignum. |
66b818fb RP |
4048 | @cindex sixteen-byte integer |
4049 | @cindex integer, 16-byte | |
f009d0ab | 4050 | @end ifset |
d0281557 | 4051 | |
95074dc3 ILT |
4052 | @node Rept |
4053 | @section @code{.rept @var{count}} | |
4054 | ||
4055 | @cindex @code{rept} directive | |
4056 | Repeat the sequence of lines between the @code{.rept} directive and the next | |
4057 | @code{.endr} directive @var{count} times. | |
4058 | ||
4059 | For example, assembling | |
4060 | ||
4061 | @example | |
4062 | .rept 3 | |
4063 | .long 0 | |
4064 | .endr | |
4065 | @end example | |
4066 | ||
4067 | is equivalent to assembling | |
4068 | ||
4069 | @example | |
4070 | .long 0 | |
4071 | .long 0 | |
4072 | .long 0 | |
4073 | @end example | |
4074 | ||
242d9c06 | 4075 | @node Sbttl |
66b818fb RP |
4076 | @section @code{.sbttl "@var{subheading}"} |
4077 | ||
4078 | @cindex @code{sbttl} directive | |
4079 | @cindex subtitles for listings | |
4080 | @cindex listing control: subtitle | |
4081 | Use @var{subheading} as the title (third line, immediately after the | |
f009d0ab | 4082 | title line) when generating assembly listings. |
66b818fb RP |
4083 | |
4084 | This directive affects subsequent pages, as well as the current page if | |
4085 | it appears within ten lines of the top of a page. | |
4086 | ||
f009d0ab | 4087 | @ifset COFF |
242d9c06 | 4088 | @node Scl |
d0281557 | 4089 | @section @code{.scl @var{class}} |
66b818fb RP |
4090 | |
4091 | @cindex @code{scl} directive | |
4092 | @cindex symbol storage class (COFF) | |
4093 | @cindex COFF symbol storage class | |
d0281557 RP |
4094 | Set the storage-class value for a symbol. This directive may only be |
4095 | used inside a @code{.def}/@code{.endef} pair. Storage class may flag | |
4096 | whether a symbol is static or external, or it may record further | |
4097 | symbolic debugging information. | |
f009d0ab | 4098 | @ifset BOUT |
d0281557 RP |
4099 | |
4100 | The @samp{.scl} directive is primarily associated with COFF output; when | |
05a0e43b RP |
4101 | configured to generate @code{b.out} output format, @code{@value{AS}} |
4102 | accepts this directive but ignores it. | |
f009d0ab RP |
4103 | @end ifset |
4104 | @end ifset | |
d0281557 | 4105 | |
242d9c06 | 4106 | @node Section |
868c3513 | 4107 | @section @code{.section @var{name}} |
66b818fb RP |
4108 | |
4109 | @cindex @code{section} directive | |
868c3513 ILT |
4110 | @cindex named section |
4111 | Use the @code{.section} directive to assemble the following code into a section | |
4112 | named @var{name}. | |
4113 | ||
4b9f4409 KR |
4114 | This directive is only supported for targets that actually support arbitrarily |
4115 | named sections; on @code{a.out} targets, for example, it is not accepted, even | |
868c3513 ILT |
4116 | with a standard @code{a.out} section name. |
4117 | ||
4118 | @ifset COFF | |
4119 | For COFF targets, the @code{.section} directive is used in one of the following | |
4120 | ways: | |
4121 | @smallexample | |
4122 | .section @var{name}[, "@var{flags}"] | |
4123 | .section @var{name}[, @var{subsegment}] | |
4124 | @end smallexample | |
4125 | ||
4126 | If the optional argument is quoted, it is taken as flags to use for the | |
4127 | section. Each flag is a single character. The following flags are recognized: | |
4128 | @table @code | |
4129 | @item b | |
4130 | bss section (uninitialized data) | |
4131 | @item n | |
4132 | section is not loaded | |
4133 | @item w | |
4134 | writable section | |
4135 | @item d | |
4136 | data section | |
35cfacf0 ILT |
4137 | @item r |
4138 | read-only section | |
868c3513 ILT |
4139 | @item x |
4140 | executable section | |
4141 | @end table | |
4142 | ||
4143 | If no flags are specified, the default flags depend upon the section name. If | |
4144 | the section name is not recognized, the default will be for the section to be | |
4145 | loaded and writable. | |
4146 | ||
4147 | If the optional argument to the @code{.section} directive is not quoted, it is | |
4148 | taken as a subsegment number (@pxref{Sub-Sections}). | |
4b9f4409 | 4149 | @end ifset |
868c3513 ILT |
4150 | |
4151 | @ifset ELF | |
4152 | For ELF targets, the @code{.section} directive is used like this: | |
4153 | @smallexample | |
4154 | .section @var{name}[, "@var{flags}"[, @@@var{type}]] | |
4155 | @end smallexample | |
4156 | The optional @var{flags} argument is a quoted string which may contain any | |
4157 | combintion of the following characters: | |
4158 | @table @code | |
4159 | @item a | |
4160 | section is allocatable | |
4161 | @item w | |
4162 | section is writable | |
4163 | @item x | |
4164 | section is executable | |
4165 | @end table | |
4166 | ||
4167 | The optional @var{type} argument may contain one of the following constants: | |
4168 | @table @code | |
4169 | @item @@progbits | |
4170 | section contains data | |
4171 | @item @@nobits | |
4172 | section does not contain data (i.e., section only occupies space) | |
4173 | @end table | |
4174 | ||
4175 | If no flags are specified, the default flags depend upon the section name. If | |
4176 | the section name is not recognized, the default will be for the section to have | |
4177 | none of the above flags: it will not be allocated in memory, nor writable, nor | |
4178 | executable. The section will contain data. | |
4179 | ||
4180 | For ELF targets, the assembler supports another type of @code{.section} | |
4181 | directive for compatibility with the Solaris assembler: | |
4182 | @smallexample | |
4183 | .section "@var{name}"[, @var{flags}...] | |
4184 | @end smallexample | |
4185 | Note that the section name is quoted. There may be a sequence of comma | |
4186 | separated flags: | |
4187 | @table @code | |
4188 | @item #alloc | |
4189 | section is allocatable | |
4190 | @item #write | |
4191 | section is writable | |
4192 | @item #execinstr | |
4193 | section is executable | |
4194 | @end table | |
f009d0ab | 4195 | @end ifset |
242d9c06 SC |
4196 | |
4197 | @node Set | |
b50e59fe | 4198 | @section @code{.set @var{symbol}, @var{expression}} |
93b45514 | 4199 | |
66b818fb RP |
4200 | @cindex @code{set} directive |
4201 | @cindex symbol value, setting | |
05a0e43b RP |
4202 | Set the value of @var{symbol} to @var{expression}. This |
4203 | changes @var{symbol}'s value and type to conform to | |
d0281557 | 4204 | @var{expression}. If @var{symbol} was flagged as external, it remains |
c6c7035c | 4205 | flagged (@pxref{Symbol Attributes}). |
93b45514 | 4206 | |
47342e8f | 4207 | You may @code{.set} a symbol many times in the same assembly. |
93b45514 RP |
4208 | |
4209 | If you @code{.set} a global symbol, the value stored in the object | |
4210 | file is the last value stored into it. | |
4211 | ||
9dcf8057 JL |
4212 | @ifset HPPA |
4213 | The syntax for @code{set} on the HPPA is | |
509d5555 | 4214 | @samp{@var{symbol} .set @var{expression}}. |
9dcf8057 JL |
4215 | @end ifset |
4216 | ||
242d9c06 | 4217 | @node Short |
b50e59fe | 4218 | @section @code{.short @var{expressions}} |
66b818fb RP |
4219 | |
4220 | @cindex @code{short} directive | |
f009d0ab RP |
4221 | @ifset GENERIC |
4222 | @code{.short} is normally the same as @samp{.word}. | |
4223 | @xref{Word,,@code{.word}}. | |
4224 | ||
7a4c8e5c | 4225 | In some configurations, however, @code{.short} and @code{.word} generate |
f009d0ab RP |
4226 | numbers of different lengths; @pxref{Machine Dependencies}. |
4227 | @end ifset | |
4228 | @ifclear GENERIC | |
4229 | @ifset W16 | |
4230 | @code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}. | |
4231 | @end ifset | |
4232 | @ifset W32 | |
b50e59fe RP |
4233 | This expects zero or more @var{expressions}, and emits |
4234 | a 16 bit number for each. | |
f009d0ab RP |
4235 | @end ifset |
4236 | @end ifclear | |
242d9c06 SC |
4237 | |
4238 | @node Single | |
b50e59fe | 4239 | @section @code{.single @var{flonums}} |
66b818fb RP |
4240 | |
4241 | @cindex @code{single} directive | |
4242 | @cindex floating point numbers (single) | |
b50e59fe | 4243 | This directive assembles zero or more flonums, separated by commas. It |
d0281557 | 4244 | has the same effect as @code{.float}. |
f009d0ab | 4245 | @ifset GENERIC |
09352a5d | 4246 | The exact kind of floating point numbers emitted depends on how |
f009d0ab RP |
4247 | @code{@value{AS}} is configured. @xref{Machine Dependencies}. |
4248 | @end ifset | |
4249 | @ifclear GENERIC | |
4250 | @ifset IEEEFLOAT | |
4251 | On the @value{TARGET} family, @code{.single} emits 32-bit floating point | |
66b818fb | 4252 | numbers in @sc{ieee} format. |
f009d0ab RP |
4253 | @end ifset |
4254 | @end ifclear | |
d0281557 | 4255 | |
f009d0ab | 4256 | @ifset COFF |
242d9c06 | 4257 | @node Size |
d0281557 | 4258 | @section @code{.size} |
66b818fb RP |
4259 | |
4260 | @cindex @code{size} directive | |
d0281557 RP |
4261 | This directive is generated by compilers to include auxiliary debugging |
4262 | information in the symbol table. It is only permitted inside | |
4263 | @code{.def}/@code{.endef} pairs. | |
f009d0ab | 4264 | @ifset BOUT |
d0281557 RP |
4265 | |
4266 | @samp{.size} is only meaningful when generating COFF format output; when | |
f009d0ab | 4267 | @code{@value{AS}} is generating @code{b.out}, it accepts this directive but |
d0281557 | 4268 | ignores it. |
f009d0ab RP |
4269 | @end ifset |
4270 | @end ifset | |
7a4c8e5c | 4271 | |
3ffb03b1 DE |
4272 | @node Sleb128 |
4273 | @section @code{.sleb128 @var{expressions}} | |
4274 | ||
4275 | @cindex @code{sleb128} directive | |
4276 | @var{sleb128} stands for ``signed little endian base 128.'' This is a | |
4277 | compact, variable length representation of numbers used by the DWARF | |
4278 | symbolic debugging format. @xref{Uleb128,@code{.uleb128}}. | |
4279 | ||
f009d0ab | 4280 | @ifclear no-space-dir |
910d7df2 C |
4281 | @node Skip |
4282 | @section @code{.skip @var{size} , @var{fill}} | |
4283 | ||
4284 | @cindex @code{skip} directive | |
4285 | @cindex filling memory | |
4286 | This directive emits @var{size} bytes, each of value @var{fill}. Both | |
4287 | @var{size} and @var{fill} are absolute expressions. If the comma and | |
4288 | @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same as | |
4289 | @samp{.space}. | |
4290 | ||
242d9c06 | 4291 | @node Space |
b50e59fe | 4292 | @section @code{.space @var{size} , @var{fill}} |
66b818fb RP |
4293 | |
4294 | @cindex @code{space} directive | |
4295 | @cindex filling memory | |
47342e8f | 4296 | This directive emits @var{size} bytes, each of value @var{fill}. Both |
93b45514 | 4297 | @var{size} and @var{fill} are absolute expressions. If the comma |
910d7df2 C |
4298 | and @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same |
4299 | as @samp{.skip}. | |
05a0e43b RP |
4300 | |
4301 | @ifset HPPA | |
4302 | @quotation | |
4303 | @emph{Warning:} @code{.space} has a completely different meaning for HPPA | |
e680d737 RP |
4304 | targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800 |
4305 | Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the | |
4306 | @code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives}, | |
4307 | for a summary. | |
05a0e43b RP |
4308 | @end quotation |
4309 | @end ifset | |
f009d0ab | 4310 | @end ifclear |
b50e59fe | 4311 | |
f009d0ab RP |
4312 | @ifset A29K |
4313 | @ifclear GENERIC | |
4314 | @node Space | |
24b1493d | 4315 | @section @code{.space} |
66b818fb | 4316 | @cindex @code{space} directive |
f009d0ab | 4317 | @end ifclear |
7a4c8e5c RP |
4318 | On the AMD 29K, this directive is ignored; it is accepted for |
4319 | compatibility with other AMD 29K assemblers. | |
b50e59fe RP |
4320 | |
4321 | @quotation | |
8babef85 | 4322 | @emph{Warning:} In most versions of the @sc{gnu} assembler, the directive |
f009d0ab | 4323 | @code{.space} has the effect of @code{.block} @xref{Machine Dependencies}. |
b50e59fe | 4324 | @end quotation |
f009d0ab | 4325 | @end ifset |
93b45514 | 4326 | |
f009d0ab | 4327 | @ifset have-stabs |
242d9c06 | 4328 | @node Stab |
b50e59fe | 4329 | @section @code{.stabd, .stabn, .stabs} |
66b818fb RP |
4330 | |
4331 | @cindex symbolic debuggers, information for | |
4332 | @cindex @code{stab@var{x}} directives | |
47342e8f | 4333 | There are three directives that begin @samp{.stab}. |
b50e59fe | 4334 | All emit symbols (@pxref{Symbols}), for use by symbolic debuggers. |
f009d0ab | 4335 | The symbols are not entered in the @code{@value{AS}} hash table: they |
d0281557 | 4336 | cannot be referenced elsewhere in the source file. |
93b45514 | 4337 | Up to five fields are required: |
f009d0ab | 4338 | |
93b45514 RP |
4339 | @table @var |
4340 | @item string | |
f009d0ab RP |
4341 | This is the symbol's name. It may contain any character except |
4342 | @samp{\000}, so is more general than ordinary symbol names. Some | |
4343 | debuggers used to code arbitrarily complex structures into symbol names | |
4344 | using this field. | |
4345 | ||
93b45514 | 4346 | @item type |
f009d0ab RP |
4347 | An absolute expression. The symbol's type is set to the low 8 bits of |
4348 | this expression. Any bit pattern is permitted, but @code{@value{LD}} | |
05a0e43b | 4349 | and debuggers choke on silly bit patterns. |
f009d0ab | 4350 | |
93b45514 | 4351 | @item other |
f009d0ab RP |
4352 | An absolute expression. The symbol's ``other'' attribute is set to the |
4353 | low 8 bits of this expression. | |
4354 | ||
93b45514 | 4355 | @item desc |
f009d0ab RP |
4356 | An absolute expression. The symbol's descriptor is set to the low 16 |
4357 | bits of this expression. | |
4358 | ||
93b45514 | 4359 | @item value |
b50e59fe | 4360 | An absolute expression which becomes the symbol's value. |
93b45514 RP |
4361 | @end table |
4362 | ||
b50e59fe | 4363 | If a warning is detected while reading a @code{.stabd}, @code{.stabn}, |
05a0e43b RP |
4364 | or @code{.stabs} statement, the symbol has probably already been created; |
4365 | you get a half-formed symbol in your object file. This is | |
b50e59fe | 4366 | compatible with earlier assemblers! |
93b45514 | 4367 | |
47342e8f | 4368 | @table @code |
66b818fb | 4369 | @cindex @code{stabd} directive |
47342e8f | 4370 | @item .stabd @var{type} , @var{other} , @var{desc} |
93b45514 RP |
4371 | |
4372 | The ``name'' of the symbol generated is not even an empty string. | |
4373 | It is a null pointer, for compatibility. Older assemblers used a | |
4374 | null pointer so they didn't waste space in object files with empty | |
4375 | strings. | |
4376 | ||
b50e59fe | 4377 | The symbol's value is set to the location counter, |
93b45514 | 4378 | relocatably. When your program is linked, the value of this symbol |
05a0e43b | 4379 | is the address of the location counter when the @code{.stabd} was |
93b45514 RP |
4380 | assembled. |
4381 | ||
66b818fb | 4382 | @cindex @code{stabn} directive |
71dd3c40 | 4383 | @item .stabn @var{type} , @var{other} , @var{desc} , @var{value} |
93b45514 RP |
4384 | The name of the symbol is set to the empty string @code{""}. |
4385 | ||
66b818fb | 4386 | @cindex @code{stabs} directive |
71dd3c40 | 4387 | @item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value} |
47342e8f RP |
4388 | All five fields are specified. |
4389 | @end table | |
f009d0ab RP |
4390 | @end ifset |
4391 | @c end have-stabs | |
d0281557 | 4392 | |
e680d737 RP |
4393 | @node String |
4394 | @section @code{.string} "@var{str}" | |
4395 | ||
4396 | @cindex string, copying to object file | |
4397 | @cindex @code{string} directive | |
4398 | ||
4399 | Copy the characters in @var{str} to the object file. You may specify more than | |
4400 | one string to copy, separated by commas. Unless otherwise specified for a | |
4401 | particular machine, the assembler marks the end of each string with a 0 byte. | |
81fcb3ff | 4402 | You can use any of the escape sequences described in @ref{Strings,,Strings}. |
e680d737 | 4403 | |
35cfacf0 ILT |
4404 | @ifset ELF |
4405 | @node Symver | |
4406 | @section @code{.symver} | |
4407 | @cindex @code{symver} directive | |
4408 | @cindex symbol versioning | |
4409 | @cindex versions of symbols | |
4410 | Use the @code{.symver} directive to bind symbols to specific version nodes | |
4411 | within a source file. This is only supported on ELF platforms, and is | |
4412 | typically used when assembling files to be linked into a shared library. | |
4413 | There are cases where it may make sense to use this in objects to be bound | |
4414 | into an application itself so as to override a versioned symbol from a | |
4415 | shared library. | |
4416 | ||
4417 | For ELF targets, the @code{.symver} directive is used like this: | |
4418 | @smallexample | |
4419 | .symver @var{name}, @var{name2@@nodename} | |
4420 | @end smallexample | |
4421 | In this case, the symbol @var{name} must exist and be defined within the file | |
4422 | being assembled. The @code{.versym} directive effectively creates a symbol | |
4423 | alias with the name @var{name2@@nodename}, and in fact the main reason that we | |
4424 | just don't try and create a regular alias is that the @var{@@} character isn't | |
4425 | permitted in symbol names. The @var{name2} part of the name is the actual name | |
4426 | of the symbol by which it will be externally referenced. The name @var{name} | |
4427 | itself is merely a name of convenience that is used so that it is possible to | |
4428 | have definitions for multiple versions of a function within a single source | |
4429 | file, and so that the compiler can unambiguously know which version of a | |
4430 | function is being mentioned. The @var{nodename} portion of the alias should be | |
4431 | the name of a node specified in the version script supplied to the linker when | |
4432 | building a shared library. If you are attempting to override a versioned | |
4433 | symbol from a shared library, then @var{nodename} should correspond to the | |
4434 | nodename of the symbol you are trying to override. | |
4435 | @end ifset | |
4436 | ||
f009d0ab | 4437 | @ifset COFF |
242d9c06 | 4438 | @node Tag |
d0281557 | 4439 | @section @code{.tag @var{structname}} |
66b818fb RP |
4440 | |
4441 | @cindex COFF structure debugging | |
4442 | @cindex structure debugging, COFF | |
4443 | @cindex @code{tag} directive | |
d0281557 RP |
4444 | This directive is generated by compilers to include auxiliary debugging |
4445 | information in the symbol table. It is only permitted inside | |
4446 | @code{.def}/@code{.endef} pairs. Tags are used to link structure | |
4447 | definitions in the symbol table with instances of those structures. | |
f009d0ab | 4448 | @ifset BOUT |
d0281557 RP |
4449 | |
4450 | @samp{.tag} is only used when generating COFF format output; when | |
f009d0ab | 4451 | @code{@value{AS}} is generating @code{b.out}, it accepts this directive but |
d0281557 | 4452 | ignores it. |
f009d0ab RP |
4453 | @end ifset |
4454 | @end ifset | |
7a4c8e5c | 4455 | |
242d9c06 | 4456 | @node Text |
24b1493d | 4457 | @section @code{.text @var{subsection}} |
66b818fb RP |
4458 | |
4459 | @cindex @code{text} directive | |
f009d0ab | 4460 | Tells @code{@value{AS}} to assemble the following statements onto the end of |
24b1493d RP |
4461 | the text subsection numbered @var{subsection}, which is an absolute |
4462 | expression. If @var{subsection} is omitted, subsection number zero | |
93b45514 RP |
4463 | is used. |
4464 | ||
242d9c06 | 4465 | @node Title |
66b818fb RP |
4466 | @section @code{.title "@var{heading}"} |
4467 | ||
4468 | @cindex @code{title} directive | |
4469 | @cindex listing control: title line | |
4470 | Use @var{heading} as the title (second line, immediately after the | |
f009d0ab | 4471 | source file name and pagenumber) when generating assembly listings. |
66b818fb RP |
4472 | |
4473 | This directive affects subsequent pages, as well as the current page if | |
4474 | it appears within ten lines of the top of a page. | |
4475 | ||
f009d0ab | 4476 | @ifset COFF |
242d9c06 | 4477 | @node Type |
d0281557 | 4478 | @section @code{.type @var{int}} |
66b818fb RP |
4479 | |
4480 | @cindex COFF symbol type | |
4481 | @cindex symbol type, COFF | |
4482 | @cindex @code{type} directive | |
d0281557 RP |
4483 | This directive, permitted only within @code{.def}/@code{.endef} pairs, |
4484 | records the integer @var{int} as the type attribute of a symbol table entry. | |
f009d0ab | 4485 | @ifset BOUT |
d0281557 RP |
4486 | |
4487 | @samp{.type} is associated only with COFF format output; when | |
f009d0ab | 4488 | @code{@value{AS}} is configured for @code{b.out} output, it accepts this |
d0281557 | 4489 | directive but ignores it. |
f009d0ab RP |
4490 | @end ifset |
4491 | @end ifset | |
d0281557 | 4492 | |
f009d0ab | 4493 | @ifset COFF |
242d9c06 | 4494 | @node Val |
d0281557 | 4495 | @section @code{.val @var{addr}} |
66b818fb RP |
4496 | |
4497 | @cindex @code{val} directive | |
4498 | @cindex COFF value attribute | |
4499 | @cindex value attribute, COFF | |
d0281557 RP |
4500 | This directive, permitted only within @code{.def}/@code{.endef} pairs, |
4501 | records the address @var{addr} as the value attribute of a symbol table | |
4502 | entry. | |
f009d0ab | 4503 | @ifset BOUT |
d0281557 | 4504 | |
f009d0ab | 4505 | @samp{.val} is used only for COFF output; when @code{@value{AS}} is |
d0281557 | 4506 | configured for @code{b.out}, it accepts this directive but ignores it. |
f009d0ab RP |
4507 | @end ifset |
4508 | @end ifset | |
7a4c8e5c | 4509 | |
3ffb03b1 DE |
4510 | @node Uleb128 |
4511 | @section @code{.uleb128 @var{expressions}} | |
4512 | ||
4513 | @cindex @code{uleb128} directive | |
4514 | @var{uleb128} stands for ``unsigned little endian base 128.'' This is a | |
4515 | compact, variable length representation of numbers used by the DWARF | |
4516 | symbolic debugging format. @xref{Sleb128,@code{.sleb128}}. | |
4517 | ||
242d9c06 | 4518 | @node Word |
b50e59fe | 4519 | @section @code{.word @var{expressions}} |
66b818fb RP |
4520 | |
4521 | @cindex @code{word} directive | |
24b1493d | 4522 | This directive expects zero or more @var{expressions}, of any section, |
b50e59fe | 4523 | separated by commas. |
f009d0ab RP |
4524 | @ifclear GENERIC |
4525 | @ifset W32 | |
4526 | For each expression, @code{@value{AS}} emits a 32-bit number. | |
4527 | @end ifset | |
4528 | @ifset W16 | |
4529 | For each expression, @code{@value{AS}} emits a 16-bit number. | |
4530 | @end ifset | |
4531 | @end ifclear | |
4532 | @ifset GENERIC | |
4533 | ||
0b5b143a | 4534 | The size of the number emitted, and its byte order, |
05a0e43b | 4535 | depend on what target computer the assembly is for. |
f009d0ab | 4536 | @end ifset |
09352a5d | 4537 | |
7a4c8e5c | 4538 | @c on amd29k, i960, sparc the "special treatment to support compilers" doesn't |
09352a5d | 4539 | @c happen---32-bit addressability, period; no long/short jumps. |
f009d0ab | 4540 | @ifset DIFF-TBL-KLUGE |
66b818fb RP |
4541 | @cindex difference tables altered |
4542 | @cindex altered difference tables | |
0b5b143a RP |
4543 | @quotation |
4544 | @emph{Warning: Special Treatment to support Compilers} | |
4545 | @end quotation | |
47342e8f | 4546 | |
f009d0ab | 4547 | @ifset GENERIC |
24b1493d RP |
4548 | Machines with a 32-bit address space, but that do less than 32-bit |
4549 | addressing, require the following special treatment. If the machine of | |
4550 | interest to you does 32-bit addressing (or doesn't require it; | |
f009d0ab | 4551 | @pxref{Machine Dependencies}), you can ignore this issue. |
7a4c8e5c | 4552 | |
f009d0ab | 4553 | @end ifset |
05a0e43b RP |
4554 | In order to assemble compiler output into something that works, |
4555 | @code{@value{AS}} occasionlly does strange things to @samp{.word} directives. | |
47342e8f | 4556 | Directives of the form @samp{.word sym1-sym2} are often emitted by |
f009d0ab | 4557 | compilers as part of jump tables. Therefore, when @code{@value{AS}} assembles a |
47342e8f | 4558 | directive of the form @samp{.word sym1-sym2}, and the difference between |
05a0e43b RP |
4559 | @code{sym1} and @code{sym2} does not fit in 16 bits, @code{@value{AS}} |
4560 | creates a @dfn{secondary jump table}, immediately before the next label. | |
4561 | This secondary jump table is preceded by a short-jump to the | |
47342e8f RP |
4562 | first byte after the secondary table. This short-jump prevents the flow |
4563 | of control from accidentally falling into the new table. Inside the | |
05a0e43b RP |
4564 | table is a long-jump to @code{sym2}. The original @samp{.word} |
4565 | contains @code{sym1} minus the address of the long-jump to | |
d0281557 | 4566 | @code{sym2}. |
47342e8f RP |
4567 | |
4568 | If there were several occurrences of @samp{.word sym1-sym2} before the | |
05a0e43b | 4569 | secondary jump table, all of them are adjusted. If there was a |
47342e8f | 4570 | @samp{.word sym3-sym4}, that also did not fit in sixteen bits, a |
05a0e43b RP |
4571 | long-jump to @code{sym4} is included in the secondary jump table, |
4572 | and the @code{.word} directives are adjusted to contain @code{sym3} | |
47342e8f | 4573 | minus the address of the long-jump to @code{sym4}; and so on, for as many |
d0281557 | 4574 | entries in the original jump table as necessary. |
09352a5d | 4575 | |
f009d0ab RP |
4576 | @ifset INTERNALS |
4577 | @emph{This feature may be disabled by compiling @code{@value{AS}} with the | |
47342e8f RP |
4578 | @samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse |
4579 | assembly language programmers. | |
f009d0ab RP |
4580 | @end ifset |
4581 | @end ifset | |
4582 | @c end DIFF-TBL-KLUGE | |
93b45514 | 4583 | |
242d9c06 | 4584 | @node Deprecated |
93b45514 | 4585 | @section Deprecated Directives |
66b818fb RP |
4586 | |
4587 | @cindex deprecated directives | |
4588 | @cindex obsolescent directives | |
93b45514 RP |
4589 | One day these directives won't work. |
4590 | They are included for compatibility with older assemblers. | |
4591 | @table @t | |
4592 | @item .abort | |
2d8e0f62 | 4593 | @item .app-file |
93b45514 RP |
4594 | @item .line |
4595 | @end table | |
4596 | ||
f009d0ab RP |
4597 | @ifset GENERIC |
4598 | @node Machine Dependencies | |
09352a5d | 4599 | @chapter Machine Dependent Features |
66b818fb RP |
4600 | |
4601 | @cindex machine dependencies | |
4602 | The machine instruction sets are (almost by definition) different on | |
f009d0ab RP |
4603 | each machine where @code{@value{AS}} runs. Floating point representations |
4604 | vary as well, and @code{@value{AS}} often supports a few additional | |
66b818fb RP |
4605 | directives or command-line options for compatibility with other |
4606 | assemblers on a particular platform. Finally, some versions of | |
f009d0ab | 4607 | @code{@value{AS}} support special pseudo-instructions for branch |
66b818fb RP |
4608 | optimization. |
4609 | ||
4610 | This chapter discusses most of these differences, though it does not | |
4611 | include details on any machine's instruction set. For details on that | |
4612 | subject, see the hardware manufacturer's manual. | |
4613 | ||
7a4c8e5c | 4614 | @menu |
910d7df2 C |
4615 | @ifset A29K |
4616 | * AMD29K-Dependent:: AMD 29K Dependent Features | |
4617 | @end ifset | |
99c4053d KR |
4618 | @ifset ARC |
4619 | * ARC-Dependent:: ARC Dependent Features | |
4620 | @end ifset | |
3ffb03b1 DE |
4621 | @ifset ARM |
4622 | * ARM-Dependent:: ARM Dependent Features | |
4623 | @end ifset | |
9a5acea8 ILT |
4624 | @ifset D10V |
4625 | * D10V-Dependent:: D10V Dependent Features | |
4626 | @end ifset | |
f009d0ab | 4627 | @ifset H8/300 |
ba487f3a | 4628 | * H8/300-Dependent:: Hitachi H8/300 Dependent Features |
f009d0ab RP |
4629 | @end ifset |
4630 | @ifset H8/500 | |
4631 | * H8/500-Dependent:: Hitachi H8/500 Dependent Features | |
4632 | @end ifset | |
9dcf8057 | 4633 | @ifset HPPA |
fb5bec49 | 4634 | * HPPA-Dependent:: HPPA Dependent Features |
9dcf8057 | 4635 | @end ifset |
910d7df2 C |
4636 | @ifset I80386 |
4637 | * i386-Dependent:: Intel 80386 Dependent Features | |
f009d0ab | 4638 | @end ifset |
f009d0ab | 4639 | @ifset I960 |
ba487f3a | 4640 | * i960-Dependent:: Intel 80960 Dependent Features |
f009d0ab RP |
4641 | @end ifset |
4642 | @ifset M680X0 | |
ba487f3a | 4643 | * M68K-Dependent:: M680x0 Dependent Features |
f009d0ab | 4644 | @end ifset |
910d7df2 C |
4645 | @ifset MIPS |
4646 | * MIPS-Dependent:: MIPS Dependent Features | |
4647 | @end ifset | |
4648 | @ifset SH | |
4649 | * SH-Dependent:: Hitachi SH Dependent Features | |
4650 | @end ifset | |
f009d0ab | 4651 | @ifset SPARC |
ba487f3a | 4652 | * Sparc-Dependent:: SPARC Dependent Features |
f009d0ab RP |
4653 | @end ifset |
4654 | @ifset Z8000 | |
ba487f3a | 4655 | * Z8000-Dependent:: Z8000 Dependent Features |
f009d0ab | 4656 | @end ifset |
910d7df2 C |
4657 | @ifset VAX |
4658 | * Vax-Dependent:: VAX Dependent Features | |
f009d0ab | 4659 | @end ifset |
7a4c8e5c RP |
4660 | @end menu |
4661 | ||
9dcf8057 | 4662 | @lowersections |
f009d0ab RP |
4663 | @end ifset |
4664 | ||
4665 | @c The following major nodes are *sections* in the GENERIC version, *chapters* | |
9dcf8057 | 4666 | @c in single-cpu versions. This is mainly achieved by @lowersections. There is a |
f009d0ab RP |
4667 | @c peculiarity: to preserve cross-references, there must be a node called |
4668 | @c "Machine Dependencies". Hence the conditional nodenames in each | |
4669 | @c major node below. Node defaulting in makeinfo requires adjacency of | |
4670 | @c node and sectioning commands; hence the repetition of @chapter BLAH | |
4671 | @c in both conditional blocks. | |
99c4053d | 4672 | |
99c4053d KR |
4673 | @ifset ARC |
4674 | @ifset GENERIC | |
4675 | @page | |
4676 | @node ARC-Dependent | |
4677 | @chapter ARC Dependent Features | |
4678 | @end ifset | |
4679 | @ifclear GENERIC | |
4680 | @node Machine Dependencies | |
4681 | @chapter ARC Dependent Features | |
4682 | @end ifclear | |
4683 | ||
4684 | @cindex ARC support | |
4685 | @menu | |
4686 | * ARC-Opts:: Options | |
4687 | * ARC-Float:: Floating Point | |
4688 | * ARC-Directives:: Sparc Machine Directives | |
4689 | @end menu | |
4690 | ||
4691 | @node ARC-Opts | |
4692 | @section Options | |
4693 | ||
4694 | @cindex options for ARC | |
4695 | @cindex ARC options | |
4696 | @cindex architectures, ARC | |
4697 | @cindex ARC architectures | |
4698 | The ARC chip family includes several successive levels (or other | |
4699 | variants) of chip, using the same core instruction set, but including | |
4700 | a few additional instructions at each level. | |
4701 | ||
4702 | By default, @code{@value{AS}} assumes the core instruction set (ARC | |
3ffb03b1 DE |
4703 | base). The @code{.cpu} pseudo-op is intended to be used to select |
4704 | the variant. | |
99c4053d KR |
4705 | |
4706 | @table @code | |
4707 | @cindex @code{-mbig-endian} option (ARC) | |
4708 | @cindex @code{-mlittle-endian} option (ARC) | |
4709 | @cindex ARC big-endian output | |
4710 | @cindex ARC little-endian output | |
4711 | @cindex big-endian output, ARC | |
4712 | @cindex little-endian output, ARC | |
4713 | @item -mbig-endian | |
4714 | @itemx -mlittle-endian | |
4715 | Any @sc{arc} configuration of @code{@value{AS}} can select big-endian or | |
4716 | little-endian output at run time (unlike most other @sc{gnu} development | |
4717 | tools, which must be configured for one or the other). Use | |
4718 | @samp{-mbig-endian} to select big-endian output, and @samp{-mlittle-endian} | |
4719 | for little-endian. | |
4720 | @end table | |
4721 | ||
4722 | @node ARC-Float | |
4723 | @section Floating Point | |
4724 | ||
4725 | @cindex floating point, ARC (@sc{ieee}) | |
4726 | @cindex ARC floating point (@sc{ieee}) | |
4727 | The ARC cpu family currently does not have hardware floating point | |
4728 | support. Software floating point support is provided by @code{GCC} | |
4729 | and uses @sc{ieee} floating-point numbers. | |
4730 | ||
4731 | @node ARC-Directives | |
4732 | @section ARC Machine Directives | |
4733 | ||
4734 | @cindex ARC machine directives | |
4735 | @cindex machine directives, ARC | |
4736 | The ARC version of @code{@value{AS}} supports the following additional | |
4737 | machine directives: | |
4738 | ||
4739 | @table @code | |
4740 | @item .cpu | |
4741 | @cindex @code{cpu} directive, SPARC | |
3ffb03b1 DE |
4742 | This must be followed by the desired cpu. |
4743 | The ARC is intended to be customizable, @code{.cpu} is used to | |
4744 | select the desired variant [though currently there are none]. | |
99c4053d KR |
4745 | |
4746 | @end table | |
4747 | ||
4748 | @end ifset | |
99c4053d | 4749 | |
f009d0ab | 4750 | @ifset A29K |
79e15b8a | 4751 | @include c-a29k.texi |
f009d0ab | 4752 | @end ifset |
b50e59fe | 4753 | |
3ffb03b1 DE |
4754 | @ifset ARM |
4755 | @include c-arm.texi | |
4756 | @end ifset | |
4757 | ||
f009d0ab RP |
4758 | @ifset Hitachi-all |
4759 | @ifclear GENERIC | |
4760 | @node Machine Dependencies | |
4761 | @chapter Machine Dependent Features | |
4762 | ||
4763 | The machine instruction sets are different on each Hitachi chip family, | |
4764 | and there are also some syntax differences among the families. This | |
4765 | chapter describes the specific @code{@value{AS}} features for each | |
4766 | family. | |
4767 | ||
4768 | @menu | |
4769 | * H8/300-Dependent:: Hitachi H8/300 Dependent Features | |
4770 | * H8/500-Dependent:: Hitachi H8/500 Dependent Features | |
f009d0ab | 4771 | * SH-Dependent:: Hitachi SH Dependent Features |
f009d0ab | 4772 | @end menu |
9dcf8057 | 4773 | @lowersections |
f009d0ab RP |
4774 | @end ifclear |
4775 | @end ifset | |
4776 | ||
9a5acea8 ILT |
4777 | @ifset D10V |
4778 | @include c-d10v.texi | |
4779 | @end ifset | |
9a5acea8 | 4780 | |
f009d0ab | 4781 | @ifset H8/300 |
79e15b8a | 4782 | @include c-h8300.texi |
f009d0ab | 4783 | @end ifset |
24b1493d | 4784 | |
79e15b8a ILT |
4785 | @ifset H8/500 |
4786 | @include c-h8500.texi | |
fb5bec49 | 4787 | @end ifset |
66b818fb | 4788 | |
79e15b8a ILT |
4789 | @ifset HPPA |
4790 | @include c-hppa.texi | |
4791 | @end ifset | |
66b818fb | 4792 | |
910d7df2 C |
4793 | @ifset I80386 |
4794 | @include c-i386.texi | |
79e15b8a | 4795 | @end ifset |
66b818fb | 4796 | |
79e15b8a ILT |
4797 | @ifset I960 |
4798 | @include c-i960.texi | |
f009d0ab RP |
4799 | @end ifset |
4800 | ||
79e15b8a ILT |
4801 | @ifset M680X0 |
4802 | @include c-m68k.texi | |
4803 | @end ifset | |
f009d0ab | 4804 | |
910d7df2 C |
4805 | @ifset MIPS |
4806 | @include c-mips.texi | |
4807 | @end ifset | |
4808 | ||
71dd3c40 ILT |
4809 | @ifset NS32K |
4810 | @include c-ns32k.texi | |
4811 | @end ifset | |
f009d0ab | 4812 | |
910d7df2 C |
4813 | @ifset SH |
4814 | @include c-sh.texi | |
79e15b8a | 4815 | @end ifset |
f009d0ab | 4816 | |
910d7df2 C |
4817 | @ifset SPARC |
4818 | @include c-sparc.texi | |
79e15b8a | 4819 | @end ifset |
fb5bec49 | 4820 | |
79e15b8a ILT |
4821 | @ifset Z8000 |
4822 | @include c-z8k.texi | |
4823 | @end ifset | |
34214344 | 4824 | |
910d7df2 C |
4825 | @ifset VAX |
4826 | @include c-vax.texi | |
34214344 KR |
4827 | @end ifset |
4828 | ||
f009d0ab RP |
4829 | @ifset GENERIC |
4830 | @c reverse effect of @down at top of generic Machine-Dep chapter | |
9dcf8057 | 4831 | @raisesections |
f009d0ab RP |
4832 | @end ifset |
4833 | ||
9a5acea8 ILT |
4834 | @node Reporting Bugs |
4835 | @chapter Reporting Bugs | |
3ffb03b1 DE |
4836 | @cindex bugs in assembler |
4837 | @cindex reporting bugs in assembler | |
9a5acea8 ILT |
4838 | |
4839 | Your bug reports play an essential role in making @code{@value{AS}} reliable. | |
4840 | ||
4841 | Reporting a bug may help you by bringing a solution to your problem, or it may | |
4842 | not. But in any case the principal function of a bug report is to help the | |
4843 | entire community by making the next version of @code{@value{AS}} work better. | |
4844 | Bug reports are your contribution to the maintenance of @code{@value{AS}}. | |
4845 | ||
4846 | In order for a bug report to serve its purpose, you must include the | |
4847 | information that enables us to fix the bug. | |
4848 | ||
4849 | @menu | |
4850 | * Bug Criteria:: Have you found a bug? | |
4851 | * Bug Reporting:: How to report bugs | |
4852 | @end menu | |
4853 | ||
4854 | @node Bug Criteria | |
4855 | @section Have you found a bug? | |
4856 | @cindex bug criteria | |
4857 | ||
4858 | If you are not sure whether you have found a bug, here are some guidelines: | |
4859 | ||
4860 | @itemize @bullet | |
4861 | @cindex fatal signal | |
4862 | @cindex assembler crash | |
4863 | @cindex crash of assembler | |
4864 | @item | |
4865 | If the assembler gets a fatal signal, for any input whatever, that is a | |
4866 | @code{@value{AS}} bug. Reliable assemblers never crash. | |
4867 | ||
4868 | @cindex error on valid input | |
4869 | @item | |
4870 | If @code{@value{AS}} produces an error message for valid input, that is a bug. | |
4871 | ||
4872 | @cindex invalid input | |
4873 | @item | |
4874 | If @code{@value{AS}} does not produce an error message for invalid input, that | |
4875 | is a bug. However, you should note that your idea of ``invalid input'' might | |
4876 | be our idea of ``an extension'' or ``support for traditional practice''. | |
4877 | ||
4878 | @item | |
4879 | If you are an experienced user of assemblers, your suggestions for improvement | |
4880 | of @code{@value{AS}} are welcome in any case. | |
4881 | @end itemize | |
4882 | ||
4883 | @node Bug Reporting | |
4884 | @section How to report bugs | |
4885 | @cindex bug reports | |
3ffb03b1 | 4886 | @cindex assembler bugs, reporting |
9a5acea8 ILT |
4887 | |
4888 | A number of companies and individuals offer support for @sc{gnu} products. If | |
4889 | you obtained @code{@value{AS}} from a support organization, we recommend you | |
4890 | contact that organization first. | |
4891 | ||
4892 | You can find contact information for many support companies and | |
4893 | individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs | |
4894 | distribution. | |
4895 | ||
4896 | In any event, we also recommend that you send bug reports for @code{@value{AS}} | |
4897 | to @samp{bug-gnu-utils@@prep.ai.mit.edu}. | |
4898 | ||
4899 | The fundamental principle of reporting bugs usefully is this: | |
4900 | @strong{report all the facts}. If you are not sure whether to state a | |
4901 | fact or leave it out, state it! | |
4902 | ||
4903 | Often people omit facts because they think they know what causes the problem | |
4904 | and assume that some details do not matter. Thus, you might assume that the | |
4905 | name of a symbol you use in an example does not matter. Well, probably it does | |
4906 | not, but one cannot be sure. Perhaps the bug is a stray memory reference which | |
4907 | happens to fetch from the location where that name is stored in memory; | |
4908 | perhaps, if the name were different, the contents of that location would fool | |
4909 | the assembler into doing the right thing despite the bug. Play it safe and | |
4910 | give a specific, complete example. That is the easiest thing for you to do, | |
4911 | and the most helpful. | |
4912 | ||
4913 | Keep in mind that the purpose of a bug report is to enable us to fix the bug if | |
4914 | it is new to us. Therefore, always write your bug reports on the assumption | |
4915 | that the bug has not been reported previously. | |
4916 | ||
4917 | Sometimes people give a few sketchy facts and ask, ``Does this ring a | |
4918 | bell?'' Those bug reports are useless, and we urge everyone to | |
4919 | @emph{refuse to respond to them} except to chide the sender to report | |
4920 | bugs properly. | |
4921 | ||
4922 | To enable us to fix the bug, you should include all these things: | |
4923 | ||
4924 | @itemize @bullet | |
4925 | @item | |
4926 | The version of @code{@value{AS}}. @code{@value{AS}} announces it if you start | |
868c3513 | 4927 | it with the @samp{--version} argument. |
9a5acea8 ILT |
4928 | |
4929 | Without this, we will not know whether there is any point in looking for | |
4930 | the bug in the current version of @code{@value{AS}}. | |
4931 | ||
4932 | @item | |
4933 | Any patches you may have applied to the @code{@value{AS}} source. | |
4934 | ||
4935 | @item | |
4936 | The type of machine you are using, and the operating system name and | |
4937 | version number. | |
4938 | ||
4939 | @item | |
4940 | What compiler (and its version) was used to compile @code{@value{AS}}---e.g. | |
4941 | ``@code{gcc-2.7}''. | |
4942 | ||
4943 | @item | |
4944 | The command arguments you gave the assembler to assemble your example and | |
4945 | observe the bug. To guarantee you will not omit something important, list them | |
4946 | all. A copy of the Makefile (or the output from make) is sufficient. | |
4947 | ||
4948 | If we were to try to guess the arguments, we would probably guess wrong | |
4949 | and then we might not encounter the bug. | |
4950 | ||
4951 | @item | |
4952 | A complete input file that will reproduce the bug. If the bug is observed when | |
4953 | the assembler is invoked via a compiler, send the assembler source, not the | |
4954 | high level language source. Most compilers will produce the assembler source | |
4955 | when run with the @samp{-S} option. If you are using @code{@value{GCC}}, use | |
4956 | the options @samp{-v --save-temps}; this will save the assembler source in a | |
4957 | file with an extension of @file{.s}, and also show you exactly how | |
4958 | @code{@value{AS}} is being run. | |
4959 | ||
4960 | @item | |
4961 | A description of what behavior you observe that you believe is | |
4962 | incorrect. For example, ``It gets a fatal signal.'' | |
4963 | ||
4964 | Of course, if the bug is that @code{@value{AS}} gets a fatal signal, then we | |
4965 | will certainly notice it. But if the bug is incorrect output, we might not | |
4966 | notice unless it is glaringly wrong. You might as well not give us a chance to | |
4967 | make a mistake. | |
4968 | ||
4969 | Even if the problem you experience is a fatal signal, you should still say so | |
4970 | explicitly. Suppose something strange is going on, such as, your copy of | |
4971 | @code{@value{AS}} is out of synch, or you have encountered a bug in the C | |
4972 | library on your system. (This has happened!) Your copy might crash and ours | |
4973 | would not. If you told us to expect a crash, then when ours fails to crash, we | |
4974 | would know that the bug was not happening for us. If you had not told us to | |
4975 | expect a crash, then we would not be able to draw any conclusion from our | |
4976 | observations. | |
4977 | ||
4978 | @item | |
4979 | If you wish to suggest changes to the @code{@value{AS}} source, send us context | |
4980 | diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p} | |
4981 | option. Always send diffs from the old file to the new file. If you even | |
4982 | discuss something in the @code{@value{AS}} source, refer to it by context, not | |
4983 | by line number. | |
4984 | ||
4985 | The line numbers in our development sources will not match those in your | |
4986 | sources. Your line numbers would convey no useful information to us. | |
4987 | @end itemize | |
4988 | ||
4989 | Here are some things that are not necessary: | |
4990 | ||
4991 | @itemize @bullet | |
4992 | @item | |
4993 | A description of the envelope of the bug. | |
4994 | ||
4995 | Often people who encounter a bug spend a lot of time investigating | |
4996 | which changes to the input file will make the bug go away and which | |
4997 | changes will not affect it. | |
4998 | ||
4999 | This is often time consuming and not very useful, because the way we | |
5000 | will find the bug is by running a single example under the debugger | |
5001 | with breakpoints, not by pure deduction from a series of examples. | |
5002 | We recommend that you save your time for something else. | |
5003 | ||
5004 | Of course, if you can find a simpler example to report @emph{instead} | |
5005 | of the original one, that is a convenience for us. Errors in the | |
5006 | output will be easier to spot, running under the debugger will take | |
5007 | less time, and so on. | |
5008 | ||
5009 | However, simplification is not vital; if you do not want to do this, | |
5010 | report the bug anyway and send us the entire test case you used. | |
5011 | ||
5012 | @item | |
5013 | A patch for the bug. | |
5014 | ||
5015 | A patch for the bug does help us if it is a good one. But do not omit | |
5016 | the necessary information, such as the test case, on the assumption that | |
5017 | a patch is all we need. We might see problems with your patch and decide | |
5018 | to fix the problem another way, or we might not understand it at all. | |
5019 | ||
5020 | Sometimes with a program as complicated as @code{@value{AS}} it is very hard to | |
5021 | construct an example that will make the program follow a certain path through | |
5022 | the code. If you do not send us the example, we will not be able to construct | |
5023 | one, so we will not be able to verify that the bug is fixed. | |
5024 | ||
5025 | And if we cannot understand what bug you are trying to fix, or why your | |
5026 | patch should be an improvement, we will not install it. A test case will | |
5027 | help us to understand. | |
5028 | ||
5029 | @item | |
5030 | A guess about what the bug is or what it depends on. | |
5031 | ||
5032 | Such guesses are usually wrong. Even we cannot guess right about such | |
5033 | things without first using the debugger to find the facts. | |
5034 | @end itemize | |
5035 | ||
9dcf8057 JL |
5036 | @node Acknowledgements |
5037 | @chapter Acknowledgements | |
5038 | ||
05a0e43b RP |
5039 | If you have contributed to @code{@value{AS}} and your name isn't listed here, |
5040 | it is not meant as a slight. We just don't know about it. Send mail to the | |
71dd3c40 ILT |
5041 | maintainer, and we'll correct the situation. Currently |
5042 | @c (January 1994), | |
5043 | the maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}). | |
9dcf8057 | 5044 | |
79e15b8a ILT |
5045 | Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any |
5046 | more details?} | |
9dcf8057 | 5047 | |
05a0e43b | 5048 | Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug |
9dcf8057 | 5049 | information and the 68k series machines, most of the preprocessing pass, and |
05a0e43b | 5050 | extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}. |
9dcf8057 JL |
5051 | |
5052 | K. Richard Pixley maintained GAS for a while, adding various enhancements and | |
5053 | many bug fixes, including merging support for several processors, breaking GAS | |
05a0e43b RP |
5054 | up to handle multiple object file format back ends (including heavy rewrite, |
5055 | testing, an integration of the coff and b.out back ends), adding configuration | |
9dcf8057 | 5056 | including heavy testing and verification of cross assemblers and file splits |
05a0e43b RP |
5057 | and renaming, converted GAS to strictly ANSI C including full prototypes, added |
5058 | support for m680[34]0 and cpu32, did considerable work on i960 including a COFF | |
5059 | port (including considerable amounts of reverse engineering), a SPARC opcode | |
5060 | file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know'' | |
9dcf8057 JL |
5061 | assertions and made them work, much other reorganization, cleanup, and lint. |
5062 | ||
5063 | Ken Raeburn wrote the high-level BFD interface code to replace most of the code | |
5064 | in format-specific I/O modules. | |
5065 | ||
5066 | The original VMS support was contributed by David L. Kashtan. Eric Youngdale | |
5067 | has done much work with it since. | |
5068 | ||
5069 | The Intel 80386 machine description was written by Eliot Dresselhaus. | |
5070 | ||
5071 | Minh Tran-Le at IntelliCorp contributed some AIX 386 support. | |
5072 | ||
5073 | The Motorola 88k machine description was contributed by Devon Bowen of Buffalo | |
5074 | University and Torbjorn Granlund of the Swedish Institute of Computer Science. | |
5075 | ||
5076 | Keith Knowles at the Open Software Foundation wrote the original MIPS back end | |
05a0e43b RP |
5077 | (@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support |
5078 | (which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to | |
5079 | support a.out format. | |
9dcf8057 JL |
5080 | |
5081 | Support for the Zilog Z8k and Hitachi H8/300 and H8/500 processors (tc-z8k, | |
5082 | tc-h8300, tc-h8500), and IEEE 695 object file format (obj-ieee), was written by | |
5083 | Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to | |
5084 | use BFD for some low-level operations, for use with the H8/300 and AMD 29k | |
5085 | targets. | |
5086 | ||
05a0e43b RP |
5087 | John Gilmore built the AMD 29000 support, added @code{.include} support, and |
5088 | simplified the configuration of which versions accept which directives. He | |
9dcf8057 | 5089 | updated the 68k machine description so that Motorola's opcodes always produced |
05a0e43b RP |
5090 | fixed-size instructions (e.g. @code{jsr}), while synthetic instructions |
5091 | remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested | |
9dcf8057 | 5092 | cross-compilation support, and one bug in relaxation that took a week and |
47c7ceb5 | 5093 | required the proverbial one-bit fix. |
9dcf8057 | 5094 | |
05a0e43b | 5095 | Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the |
9dcf8057 | 5096 | 68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix), |
910d7df2 C |
5097 | added support for MIPS ECOFF and ELF targets, wrote the initial RS/6000 and |
5098 | PowerPC assembler, and made a few other minor patches. | |
9dcf8057 JL |
5099 | |
5100 | Steve Chamberlain made @code{@value{AS}} able to generate listings. | |
5101 | ||
05a0e43b | 5102 | Hewlett-Packard contributed support for the HP9000/300. |
9dcf8057 | 5103 | |
05a0e43b RP |
5104 | Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM) |
5105 | along with a fairly extensive HPPA testsuite (for both SOM and ELF object | |
5106 | formats). This work was supported by both the Center for Software Science at | |
5107 | the University of Utah and Cygnus Support. | |
9dcf8057 JL |
5108 | |
5109 | Support for ELF format files has been worked on by Mark Eichin of Cygnus | |
5110 | Support (original, incomplete implementation for SPARC), Pete Hoogenboom and | |
5111 | Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open | |
5112 | Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc, | |
5113 | and some initial 64-bit support). | |
5114 | ||
8a51eeaf TT |
5115 | Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote GAS and BFD |
5116 | support for openVMS/Alpha. | |
910d7df2 | 5117 | |
9dcf8057 JL |
5118 | Several engineers at Cygnus Support have also provided many small bug fixes and |
5119 | configuration enhancements. | |
5120 | ||
5121 | Many others have contributed large or small bugfixes and enhancements. If | |
05a0e43b RP |
5122 | you have contributed significant work and are not mentioned on this list, and |
5123 | want to be, let us know. Some of the history has been lost; we are not | |
9dcf8057 JL |
5124 | intentionally leaving anyone out. |
5125 | ||
242d9c06 | 5126 | @node Index |
66b818fb RP |
5127 | @unnumbered Index |
5128 | ||
5129 | @printindex cp | |
5130 | ||
93b45514 RP |
5131 | @contents |
5132 | @bye | |
9dcf8057 JL |
5133 | @c Local Variables: |
5134 | @c fill-column: 79 | |
5135 | @c End: |