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1 | @c Copyright (C) 1991, 92, 93, 94, 95, 96, 1997 Free Software Foundation, Inc. |
2 | @c This is part of the GAS manual. | |
3 | @c For copying conditions, see the file as.texinfo. | |
4 | @ifset GENERIC | |
5 | @page | |
6 | @node M68K-Dependent | |
7 | @chapter M680x0 Dependent Features | |
8 | @end ifset | |
9 | @ifclear GENERIC | |
10 | @node Machine Dependencies | |
11 | @chapter M680x0 Dependent Features | |
12 | @end ifclear | |
13 | ||
14 | @cindex M680x0 support | |
15 | @menu | |
16 | * M68K-Opts:: M680x0 Options | |
17 | * M68K-Syntax:: Syntax | |
18 | * M68K-Moto-Syntax:: Motorola Syntax | |
19 | * M68K-Float:: Floating Point | |
20 | * M68K-Directives:: 680x0 Machine Directives | |
21 | * M68K-opcodes:: Opcodes | |
22 | @end menu | |
23 | ||
24 | @node M68K-Opts | |
25 | @section M680x0 Options | |
26 | ||
27 | @cindex options, M680x0 | |
28 | @cindex M680x0 options | |
29 | The Motorola 680x0 version of @code{@value{AS}} has a few machine | |
30 | dependent options. | |
31 | ||
32 | @cindex @samp{-l} option, M680x0 | |
33 | You can use the @samp{-l} option to shorten the size of references to undefined | |
34 | symbols. If you do not use the @samp{-l} option, references to undefined | |
35 | symbols are wide enough for a full @code{long} (32 bits). (Since | |
36 | @code{@value{AS}} cannot know where these symbols end up, @code{@value{AS}} can | |
37 | only allocate space for the linker to fill in later. Since @code{@value{AS}} | |
38 | does not know how far away these symbols are, it allocates as much space as it | |
39 | can.) If you use this option, the references are only one word wide (16 bits). | |
40 | This may be useful if you want the object file to be as small as possible, and | |
41 | you know that the relevant symbols are always less than 17 bits away. | |
42 | ||
43 | @cindex @samp{--register-prefix-optional} option, M680x0 | |
44 | For some configurations, especially those where the compiler normally | |
45 | does not prepend an underscore to the names of user variables, the | |
46 | assembler requires a @samp{%} before any use of a register name. This | |
47 | is intended to let the assembler distinguish between C variables and | |
48 | functions named @samp{a0} through @samp{a7}, and so on. The @samp{%} is | |
49 | always accepted, but is not required for certain configurations, notably | |
50 | @samp{sun3}. The @samp{--register-prefix-optional} option may be used | |
51 | to permit omitting the @samp{%} even for configurations for which it is | |
52 | normally required. If this is done, it will generally be impossible to | |
53 | refer to C variables and functions with the same names as register | |
54 | names. | |
55 | ||
56 | @cindex @samp{--bitwise-or} option, M680x0 | |
57 | Normally the character @samp{|} is treated as a comment character, which | |
58 | means that it can not be used in expressions. The @samp{--bitwise-or} | |
59 | option turns @samp{|} into a normal character. In this mode, you must | |
60 | either use C style comments, or start comments with a @samp{#} character | |
61 | at the beginning of a line. | |
62 | ||
63 | @cindex @samp{--base-size-default-16} | |
64 | @cindex @samp{--base-size-default-32} | |
65 | If you use an addressing mode with a base register without specifying | |
66 | the size, @code{@value{AS}} will normally use the full 32 bit value. | |
67 | For example, the addressing mode @samp{%a0@@(%d0)} is equivalent to | |
68 | @samp{%a0@@(%d0:l)}. You may use the @samp{--base-size-default-16} | |
69 | option to tell @code{@value{AS}} to default to using the 16 bit value. | |
70 | In this case, @samp{%a0@@(%d0)} is equivalent to @samp{%a0@@(%d0:w)}. | |
71 | You may use the @samp{--base-size-default-32} option to restore the | |
72 | default behaviour. | |
73 | ||
74 | @cindex @samp{--disp-size-default-16} | |
75 | @cindex @samp{--disp-size-default-32} | |
76 | If you use an addressing mode with a displacement, and the value of the | |
77 | displacement is not known, @code{@value{AS}} will normally assume that | |
78 | the value is 32 bits. For example, if the symbol @samp{disp} has not | |
79 | been defined, @code{@value{AS}} will assemble the addressing mode | |
80 | @samp{%a0@@(disp,%d0)} as though @samp{disp} is a 32 bit value. You may | |
81 | use the @samp{--disp-size-default-16} option to tell @code{@value{AS}} | |
82 | to instead assume that the displacement is 16 bits. In this case, | |
83 | @code{@value{AS}} will assemble @samp{%a0@@(disp,%d0)} as though | |
84 | @samp{disp} is a 16 bit value. You may use the | |
85 | @samp{--disp-size-default-32} option to restore the default behaviour. | |
86 | ||
87 | @cindex @samp{-m68000} and related options | |
88 | @cindex architecture options, M680x0 | |
89 | @cindex M680x0 architecture options | |
90 | @code{@value{AS}} can assemble code for several different members of the | |
91 | Motorola 680x0 family. The default depends upon how @code{@value{AS}} | |
92 | was configured when it was built; normally, the default is to assemble | |
93 | code for the 68020 microprocessor. The following options may be used to | |
94 | change the default. These options control which instructions and | |
95 | addressing modes are permitted. The members of the 680x0 family are | |
96 | very similar. For detailed information about the differences, see the | |
97 | Motorola manuals. | |
98 | ||
99 | @table @samp | |
100 | @item -m68000 | |
101 | @itemx -m68ec000 | |
102 | @itemx -m68hc000 | |
103 | @itemx -m68hc001 | |
104 | @itemx -m68008 | |
105 | @itemx -m68302 | |
106 | @itemx -m68306 | |
107 | @itemx -m68307 | |
108 | @itemx -m68322 | |
109 | @itemx -m68356 | |
110 | Assemble for the 68000. @samp{-m68008}, @samp{-m68302}, and so on are synonyms | |
111 | for @samp{-m68000}, since the chips are the same from the point of view | |
112 | of the assembler. | |
113 | ||
114 | @item -m68010 | |
115 | Assemble for the 68010. | |
116 | ||
117 | @item -m68020 | |
118 | @itemx -m68ec020 | |
119 | Assemble for the 68020. This is normally the default. | |
120 | ||
121 | @item -m68030 | |
122 | @itemx -m68ec030 | |
123 | Assemble for the 68030. | |
124 | ||
125 | @item -m68040 | |
126 | @itemx -m68ec040 | |
127 | Assemble for the 68040. | |
128 | ||
129 | @item -m68060 | |
130 | @itemx -m68ec060 | |
131 | Assemble for the 68060. | |
132 | ||
133 | @item -mcpu32 | |
134 | @itemx -m68330 | |
135 | @itemx -m68331 | |
136 | @itemx -m68332 | |
137 | @itemx -m68333 | |
138 | @itemx -m68334 | |
139 | @itemx -m68336 | |
140 | @itemx -m68340 | |
141 | @itemx -m68341 | |
142 | @itemx -m68349 | |
143 | @itemx -m68360 | |
144 | Assemble for the CPU32 family of chips. | |
145 | ||
146 | @item -m5200 | |
147 | Assemble for the ColdFire family of chips. | |
148 | ||
149 | @item -m68881 | |
150 | @itemx -m68882 | |
151 | Assemble 68881 floating point instructions. This is the default for the | |
152 | 68020, 68030, and the CPU32. The 68040 and 68060 always support | |
153 | floating point instructions. | |
154 | ||
155 | @item -mno-68881 | |
156 | Do not assemble 68881 floating point instructions. This is the default | |
157 | for 68000 and the 68010. The 68040 and 68060 always support floating | |
158 | point instructions, even if this option is used. | |
159 | ||
160 | @item -m68851 | |
161 | Assemble 68851 MMU instructions. This is the default for the 68020, | |
162 | 68030, and 68060. The 68040 accepts a somewhat different set of MMU | |
163 | instructions; @samp{-m68851} and @samp{-m68040} should not be used | |
164 | together. | |
165 | ||
166 | @item -mno-68851 | |
167 | Do not assemble 68851 MMU instructions. This is the default for the | |
168 | 68000, 68010, and the CPU32. The 68040 accepts a somewhat different set | |
169 | of MMU instructions. | |
170 | @end table | |
171 | ||
172 | @node M68K-Syntax | |
173 | @section Syntax | |
174 | ||
175 | @cindex @sc{mit} | |
176 | This syntax for the Motorola 680x0 was developed at @sc{mit}. | |
177 | ||
178 | @cindex M680x0 syntax | |
179 | @cindex syntax, M680x0 | |
180 | @cindex M680x0 size modifiers | |
181 | @cindex size modifiers, M680x0 | |
182 | The 680x0 version of @code{@value{AS}} uses instructions names and | |
183 | syntax compatible with the Sun assembler. Intervening periods are | |
184 | ignored; for example, @samp{movl} is equivalent to @samp{mov.l}. | |
185 | ||
186 | In the following table @var{apc} stands for any of the address registers | |
187 | (@samp{%a0} through @samp{%a7}), the program counter (@samp{%pc}), the | |
188 | zero-address relative to the program counter (@samp{%zpc}), a suppressed | |
189 | address register (@samp{%za0} through @samp{%za7}), or it may be omitted | |
190 | entirely. The use of @var{size} means one of @samp{w} or @samp{l}, and | |
191 | it may be omitted, along with the leading colon, unless a scale is also | |
192 | specified. The use of @var{scale} means one of @samp{1}, @samp{2}, | |
193 | @samp{4}, or @samp{8}, and it may always be omitted along with the | |
194 | leading colon. | |
195 | ||
196 | @cindex M680x0 addressing modes | |
197 | @cindex addressing modes, M680x0 | |
198 | The following addressing modes are understood: | |
199 | @table @dfn | |
200 | @item Immediate | |
201 | @samp{#@var{number}} | |
202 | ||
203 | @item Data Register | |
204 | @samp{%d0} through @samp{%d7} | |
205 | ||
206 | @item Address Register | |
207 | @samp{%a0} through @samp{%a7}@* | |
208 | @samp{%a7} is also known as @samp{%sp}, i.e. the Stack Pointer. @code{%a6} | |
209 | is also known as @samp{%fp}, the Frame Pointer. | |
210 | ||
211 | @item Address Register Indirect | |
212 | @samp{%a0@@} through @samp{%a7@@} | |
213 | ||
214 | @item Address Register Postincrement | |
215 | @samp{%a0@@+} through @samp{%a7@@+} | |
216 | ||
217 | @item Address Register Predecrement | |
218 | @samp{%a0@@-} through @samp{%a7@@-} | |
219 | ||
220 | @item Indirect Plus Offset | |
221 | @samp{@var{apc}@@(@var{number})} | |
222 | ||
223 | @item Index | |
224 | @samp{@var{apc}@@(@var{number},@var{register}:@var{size}:@var{scale})} | |
225 | ||
226 | The @var{number} may be omitted. | |
227 | ||
228 | @item Postindex | |
229 | @samp{@var{apc}@@(@var{number})@@(@var{onumber},@var{register}:@var{size}:@var{scale})} | |
230 | ||
231 | The @var{onumber} or the @var{register}, but not both, may be omitted. | |
232 | ||
233 | @item Preindex | |
234 | @samp{@var{apc}@@(@var{number},@var{register}:@var{size}:@var{scale})@@(@var{onumber})} | |
235 | ||
236 | The @var{number} may be omitted. Omitting the @var{register} produces | |
237 | the Postindex addressing mode. | |
238 | ||
239 | @item Absolute | |
240 | @samp{@var{symbol}}, or @samp{@var{digits}}, optionally followed by | |
241 | @samp{:b}, @samp{:w}, or @samp{:l}. | |
242 | @end table | |
243 | ||
244 | @node M68K-Moto-Syntax | |
245 | @section Motorola Syntax | |
246 | ||
247 | @cindex Motorola syntax for the 680x0 | |
248 | @cindex alternate syntax for the 680x0 | |
249 | ||
250 | The standard Motorola syntax for this chip differs from the syntax | |
251 | already discussed (@pxref{M68K-Syntax,,Syntax}). @code{@value{AS}} can | |
252 | accept Motorola syntax for operands, even if @sc{mit} syntax is used for | |
253 | other operands in the same instruction. The two kinds of syntax are | |
254 | fully compatible. | |
255 | ||
256 | In the following table @var{apc} stands for any of the address registers | |
257 | (@samp{%a0} through @samp{%a7}), the program counter (@samp{%pc}), the | |
258 | zero-address relative to the program counter (@samp{%zpc}), or a | |
259 | suppressed address register (@samp{%za0} through @samp{%za7}). The use | |
260 | of @var{size} means one of @samp{w} or @samp{l}, and it may always be | |
261 | omitted along with the leading dot. The use of @var{scale} means one of | |
262 | @samp{1}, @samp{2}, @samp{4}, or @samp{8}, and it may always be omitted | |
263 | along with the leading asterisk. | |
264 | ||
265 | The following additional addressing modes are understood: | |
266 | ||
267 | @table @dfn | |
268 | @item Address Register Indirect | |
269 | @samp{(%a0)} through @samp{(%a7)}@* | |
270 | @samp{%a7} is also known as @samp{%sp}, i.e. the Stack Pointer. @code{%a6} | |
271 | is also known as @samp{%fp}, the Frame Pointer. | |
272 | ||
273 | @item Address Register Postincrement | |
274 | @samp{(%a0)+} through @samp{(%a7)+} | |
275 | ||
276 | @item Address Register Predecrement | |
277 | @samp{-(%a0)} through @samp{-(%a7)} | |
278 | ||
279 | @item Indirect Plus Offset | |
280 | @samp{@var{number}(@var{%a0})} through @samp{@var{number}(@var{%a7})}, | |
281 | or @samp{@var{number}(@var{%pc})}. | |
282 | ||
283 | The @var{number} may also appear within the parentheses, as in | |
284 | @samp{(@var{number},@var{%a0})}. When used with the @var{pc}, the | |
285 | @var{number} may be omitted (with an address register, omitting the | |
286 | @var{number} produces Address Register Indirect mode). | |
287 | ||
288 | @item Index | |
289 | @samp{@var{number}(@var{apc},@var{register}.@var{size}*@var{scale})} | |
290 | ||
291 | The @var{number} may be omitted, or it may appear within the | |
292 | parentheses. The @var{apc} may be omitted. The @var{register} and the | |
293 | @var{apc} may appear in either order. If both @var{apc} and | |
294 | @var{register} are address registers, and the @var{size} and @var{scale} | |
295 | are omitted, then the first register is taken as the base register, and | |
296 | the second as the index register. | |
297 | ||
298 | @item Postindex | |
299 | @samp{([@var{number},@var{apc}],@var{register}.@var{size}*@var{scale},@var{onumber})} | |
300 | ||
301 | The @var{onumber}, or the @var{register}, or both, may be omitted. | |
302 | Either the @var{number} or the @var{apc} may be omitted, but not both. | |
303 | ||
304 | @item Preindex | |
305 | @samp{([@var{number},@var{apc},@var{register}.@var{size}*@var{scale}],@var{onumber})} | |
306 | ||
307 | The @var{number}, or the @var{apc}, or the @var{register}, or any two of | |
308 | them, may be omitted. The @var{onumber} may be omitted. The | |
309 | @var{register} and the @var{apc} may appear in either order. If both | |
310 | @var{apc} and @var{register} are address registers, and the @var{size} | |
311 | and @var{scale} are omitted, then the first register is taken as the | |
312 | base register, and the second as the index register. | |
313 | @end table | |
314 | ||
315 | @node M68K-Float | |
316 | @section Floating Point | |
317 | ||
318 | @cindex floating point, M680x0 | |
319 | @cindex M680x0 floating point | |
320 | Packed decimal (P) format floating literals are not supported. | |
321 | Feel free to add the code! | |
322 | ||
323 | The floating point formats generated by directives are these. | |
324 | ||
325 | @table @code | |
326 | @cindex @code{float} directive, M680x0 | |
327 | @item .float | |
328 | @code{Single} precision floating point constants. | |
329 | ||
330 | @cindex @code{double} directive, M680x0 | |
331 | @item .double | |
332 | @code{Double} precision floating point constants. | |
333 | ||
334 | @cindex @code{extend} directive M680x0 | |
335 | @cindex @code{ldouble} directive M680x0 | |
336 | @item .extend | |
337 | @itemx .ldouble | |
338 | @code{Extended} precision (@code{long double}) floating point constants. | |
339 | @end table | |
340 | ||
341 | @node M68K-Directives | |
342 | @section 680x0 Machine Directives | |
343 | ||
344 | @cindex M680x0 directives | |
345 | @cindex directives, M680x0 | |
346 | In order to be compatible with the Sun assembler the 680x0 assembler | |
347 | understands the following directives. | |
348 | ||
349 | @table @code | |
350 | @cindex @code{data1} directive, M680x0 | |
351 | @item .data1 | |
352 | This directive is identical to a @code{.data 1} directive. | |
353 | ||
354 | @cindex @code{data2} directive, M680x0 | |
355 | @item .data2 | |
356 | This directive is identical to a @code{.data 2} directive. | |
357 | ||
358 | @cindex @code{even} directive, M680x0 | |
359 | @item .even | |
360 | This directive is a special case of the @code{.align} directive; it | |
361 | aligns the output to an even byte boundary. | |
362 | ||
363 | @cindex @code{skip} directive, M680x0 | |
364 | @item .skip | |
365 | This directive is identical to a @code{.space} directive. | |
366 | @end table | |
367 | ||
368 | @need 2000 | |
369 | @node M68K-opcodes | |
370 | @section Opcodes | |
371 | ||
372 | @cindex M680x0 opcodes | |
373 | @cindex opcodes, M680x0 | |
374 | @cindex instruction set, M680x0 | |
375 | @c doc@cygnus.com: I don't see any point in the following | |
376 | @c paragraph. Bugs are bugs; how does saying this | |
377 | @c help anyone? | |
378 | @ignore | |
379 | Danger: Several bugs have been found in the opcode table (and | |
380 | fixed). More bugs may exist. Be careful when using obscure | |
381 | instructions. | |
382 | @end ignore | |
383 | ||
384 | @menu | |
385 | * M68K-Branch:: Branch Improvement | |
386 | * M68K-Chars:: Special Characters | |
387 | @end menu | |
388 | ||
389 | @node M68K-Branch | |
390 | @subsection Branch Improvement | |
391 | ||
392 | @cindex pseudo-opcodes, M680x0 | |
393 | @cindex M680x0 pseudo-opcodes | |
394 | @cindex branch improvement, M680x0 | |
395 | @cindex M680x0 branch improvement | |
396 | Certain pseudo opcodes are permitted for branch instructions. | |
397 | They expand to the shortest branch instruction that reach the | |
398 | target. Generally these mnemonics are made by substituting @samp{j} for | |
399 | @samp{b} at the start of a Motorola mnemonic. | |
400 | ||
401 | The following table summarizes the pseudo-operations. A @code{*} flags | |
402 | cases that are more fully described after the table: | |
403 | ||
404 | @smallexample | |
405 | Displacement | |
406 | +------------------------------------------------- | |
407 | | 68020 68000/10 | |
408 | Pseudo-Op |BYTE WORD LONG LONG non-PC relative | |
409 | +------------------------------------------------- | |
410 | jbsr |bsrs bsr bsrl jsr jsr | |
411 | jra |bras bra bral jmp jmp | |
412 | * jXX |bXXs bXX bXXl bNXs;jmpl bNXs;jmp | |
413 | * dbXX |dbXX dbXX dbXX; bra; jmpl | |
414 | * fjXX |fbXXw fbXXw fbXXl fbNXw;jmp | |
415 | ||
416 | XX: condition | |
417 | NX: negative of condition XX | |
418 | ||
419 | @end smallexample | |
420 | @center @code{*}---see full description below | |
421 | ||
422 | @table @code | |
423 | @item jbsr | |
424 | @itemx jra | |
425 | These are the simplest jump pseudo-operations; they always map to one | |
426 | particular machine instruction, depending on the displacement to the | |
427 | branch target. | |
428 | ||
429 | @item j@var{XX} | |
430 | Here, @samp{j@var{XX}} stands for an entire family of pseudo-operations, | |
431 | where @var{XX} is a conditional branch or condition-code test. The full | |
432 | list of pseudo-ops in this family is: | |
433 | @smallexample | |
434 | jhi jls jcc jcs jne jeq jvc | |
435 | jvs jpl jmi jge jlt jgt jle | |
436 | @end smallexample | |
437 | ||
438 | For the cases of non-PC relative displacements and long displacements on | |
439 | the 68000 or 68010, @code{@value{AS}} issues a longer code fragment in terms of | |
440 | @var{NX}, the opposite condition to @var{XX}. For example, for the | |
441 | non-PC relative case: | |
442 | @smallexample | |
443 | j@var{XX} foo | |
444 | @end smallexample | |
445 | gives | |
446 | @smallexample | |
447 | b@var{NX}s oof | |
448 | jmp foo | |
449 | oof: | |
450 | @end smallexample | |
451 | ||
452 | @item db@var{XX} | |
453 | The full family of pseudo-operations covered here is | |
454 | @smallexample | |
455 | dbhi dbls dbcc dbcs dbne dbeq dbvc | |
456 | dbvs dbpl dbmi dbge dblt dbgt dble | |
457 | dbf dbra dbt | |
458 | @end smallexample | |
459 | ||
460 | Other than for word and byte displacements, when the source reads | |
461 | @samp{db@var{XX} foo}, @code{@value{AS}} emits | |
462 | @smallexample | |
463 | db@var{XX} oo1 | |
464 | bra oo2 | |
465 | oo1:jmpl foo | |
466 | oo2: | |
467 | @end smallexample | |
468 | ||
469 | @item fj@var{XX} | |
470 | This family includes | |
471 | @smallexample | |
472 | fjne fjeq fjge fjlt fjgt fjle fjf | |
473 | fjt fjgl fjgle fjnge fjngl fjngle fjngt | |
474 | fjnle fjnlt fjoge fjogl fjogt fjole fjolt | |
475 | fjor fjseq fjsf fjsne fjst fjueq fjuge | |
476 | fjugt fjule fjult fjun | |
477 | @end smallexample | |
478 | ||
479 | For branch targets that are not PC relative, @code{@value{AS}} emits | |
480 | @smallexample | |
481 | fb@var{NX} oof | |
482 | jmp foo | |
483 | oof: | |
484 | @end smallexample | |
485 | when it encounters @samp{fj@var{XX} foo}. | |
486 | ||
487 | @end table | |
488 | ||
489 | @node M68K-Chars | |
490 | @subsection Special Characters | |
491 | ||
492 | @cindex special characters, M680x0 | |
493 | @cindex M680x0 immediate character | |
494 | @cindex immediate character, M680x0 | |
495 | @cindex M680x0 line comment character | |
496 | @cindex line comment character, M680x0 | |
497 | @cindex comments, M680x0 | |
498 | The immediate character is @samp{#} for Sun compatibility. The | |
499 | line-comment character is @samp{|} (unless the @samp{--bitwise-or} | |
500 | option is used). If a @samp{#} appears at the beginning of a line, it | |
501 | is treated as a comment unless it looks like @samp{# line file}, in | |
502 | which case it is treated normally. | |
503 |