1 \input texinfo @c -*-Texinfo-*-
2 @c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4 @c Free Software Foundation, Inc.
5 @c UPDATE!! On future updates--
6 @c (1) check for new machine-dep cmdline options in
7 @c md_parse_option definitions in config/tc-*.c
8 @c (2) for platform-specific directives, examine md_pseudo_op
10 @c (3) for object-format specific directives, examine obj_pseudo_op
12 @c (4) portable directives in potable[] in read.c
16 @macro gcctabopt{body}
19 @c defaults, config file may override:
22 @include asconfig.texi
27 @c Configure for the generation of man pages
64 @c common OR combinations of conditions
84 @set abnormal-separator
88 @settitle Using @value{AS}
91 @settitle Using @value{AS} (@value{TARGET})
93 @setchapternewpage odd
98 @c WARE! Some of the machine-dependent sections contain tables of machine
99 @c instructions. Except in multi-column format, these tables look silly.
100 @c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so
101 @c the multi-col format is faked within @example sections.
103 @c Again unfortunately, the natural size that fits on a page, for these tables,
104 @c is different depending on whether or not smallbook is turned on.
105 @c This matters, because of order: text flow switches columns at each page
108 @c The format faked in this source works reasonably well for smallbook,
109 @c not well for the default large-page format. This manual expects that if you
110 @c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the
111 @c tables in question. You can turn on one without the other at your
112 @c discretion, of course.
115 @c the insn tables look just as silly in info files regardless of smallbook,
116 @c might as well show 'em anyways.
122 * As: (as). The GNU assembler.
123 * Gas: (as). The GNU assembler.
132 This file documents the GNU Assembler "@value{AS}".
134 @c man begin COPYRIGHT
135 Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002 Free Software Foundation, Inc.
137 Permission is granted to copy, distribute and/or modify this document
138 under the terms of the GNU Free Documentation License, Version 1.1
139 or any later version published by the Free Software Foundation;
140 with no Invariant Sections, with no Front-Cover Texts, and with no
141 Back-Cover Texts. A copy of the license is included in the
142 section entitled "GNU Free Documentation License".
147 Permission is granted to process this file through Tex and print the
148 results, provided the printed document carries copying permission
149 notice identical to this one except for the removal of this paragraph
150 (this paragraph not being relevant to the printed manual).
156 @title Using @value{AS}
157 @subtitle The @sc{gnu} Assembler
159 @subtitle for the @value{TARGET} family
162 @subtitle Version @value{VERSION}
165 The Free Software Foundation Inc. thanks The Nice Computer
166 Company of Australia for loaning Dean Elsner to write the
167 first (Vax) version of @command{as} for Project @sc{gnu}.
168 The proprietors, management and staff of TNCCA thank FSF for
169 distracting the boss while they got some work
172 @author Dean Elsner, Jay Fenlason & friends
176 \hfill {\it Using {\tt @value{AS}}}\par
177 \hfill Edited by Cygnus Support\par
179 %"boxit" macro for figures:
180 %Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3)
181 \gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt
182 \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil
183 #2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline
184 \gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box
187 @vskip 0pt plus 1filll
188 Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002 Free Software Foundation, Inc.
190 Permission is granted to copy, distribute and/or modify this document
191 under the terms of the GNU Free Documentation License, Version 1.1
192 or any later version published by the Free Software Foundation;
193 with no Invariant Sections, with no Front-Cover Texts, and with no
194 Back-Cover Texts. A copy of the license is included in the
195 section entitled "GNU Free Documentation License".
201 @top Using @value{AS}
203 This file is a user guide to the @sc{gnu} assembler @command{@value{AS}} version
206 This version of the file describes @command{@value{AS}} configured to generate
207 code for @value{TARGET} architectures.
210 This document is distributed under the terms of the GNU Free
211 Documentation License. A copy of the license is included in the
212 section entitled "GNU Free Documentation License".
215 * Overview:: Overview
216 * Invoking:: Command-Line Options
218 * Sections:: Sections and Relocation
220 * Expressions:: Expressions
221 * Pseudo Ops:: Assembler Directives
222 * Machine Dependencies:: Machine Dependent Features
223 * Reporting Bugs:: Reporting Bugs
224 * Acknowledgements:: Who Did What
225 * GNU Free Documentation License:: GNU Free Documentation License
233 This manual is a user guide to the @sc{gnu} assembler @command{@value{AS}}.
235 This version of the manual describes @command{@value{AS}} configured to generate
236 code for @value{TARGET} architectures.
240 @cindex invocation summary
241 @cindex option summary
242 @cindex summary of options
243 Here is a brief summary of how to invoke @command{@value{AS}}. For details,
244 @pxref{Invoking,,Command-Line Options}.
246 @c man title AS the portable GNU assembler.
250 gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}.
254 @c We don't use deffn and friends for the following because they seem
255 @c to be limited to one line for the header.
257 @c man begin SYNOPSIS
258 @value{AS} [@b{-a}[@b{cdhlns}][=@var{file}]] [@b{-D}] [@b{--defsym} @var{sym}=@var{val}]
259 [@b{-f}] [@b{--gstabs}] [@b{--gdwarf2}] [@b{--help}] [@b{-I} @var{dir}]
260 [@b{-J}] [@b{-K}] [@b{-L}]
261 [@b{--listing-lhs-width}=@var{NUM}] [@b{--listing-lhs-width2}=@var{NUM}]
262 [@b{--listing-rhs-width}=@var{NUM}] [@b{--listing-cont-lines}=@var{NUM}]
263 [@b{--keep-locals}] [@b{-o} @var{objfile}] [@b{-R}] [@b{--statistics}] [@b{-v}]
264 [@b{-version}] [@b{--version}] [@b{-W}] [@b{--warn}] [@b{--fatal-warnings}]
265 [@b{-w}] [@b{-x}] [@b{-Z}] [@b{--target-help}] [@var{target-options}]
266 [@b{--}|@var{files} @dots{}]
268 @c Target dependent options are listed below. Keep the list sorted.
269 @c Add an empty line for separation.
271 @c am29k has no machine-dependent assembler options
275 @emph{Target Alpha options:}
277 [@b{-mdebug} | @b{-no-mdebug}]
278 [@b{-relax}] [@b{-g}] [@b{-G@var{size}}]
279 [@b{-F}] [@b{-32addr}]
283 @emph{Target ARC options:}
289 @emph{Target ARM options:}
290 @c Don't document the deprecated options
291 [@b{-mcpu}=@var{processor}[+@var{extension}@dots{}]]
292 [@b{-march}=@var{architecture}[+@var{extension}@dots{}]]
293 [@b{-mfpu}=@var{floating-point-fromat}]
296 [@b{-mapcs-32}|@b{-mapcs-26}|@b{-mapcs-float}|
297 @b{-mapcs-reentrant}]
298 [@b{-mthumb-interwork}] [@b{-moabi}] [@b{-k}]
302 @emph{Target CRIS options:}
303 [@b{--underscore} | @b{--no-underscore}]
305 [@b{--emulation=criself} | @b{--emulation=crisaout}]
306 @c Deprecated -- deliberately not documented.
311 @emph{Target D10V options:}
316 @emph{Target D30V options:}
317 [@b{-O}|@b{-n}|@b{-N}]
320 @c Hitachi family chips have no machine-dependent assembler options
323 @c HPPA has no machine-dependent assembler options (yet).
327 @emph{Target i386 options:}
332 @emph{Target i960 options:}
333 @c see md_parse_option in tc-i960.c
334 [@b{-ACA}|@b{-ACA_A}|@b{-ACB}|@b{-ACC}|@b{-AKA}|@b{-AKB}|
336 [@b{-b}] [@b{-no-relax}]
340 @emph{Target IA-64 options:}
341 [@b{-mconstant-gp}|@b{-mauto-pic}]
342 [@b{-milp32}|@b{-milp64}|@b{-mlp64}|@b{-mp64}]
344 [@b{-x}|@b{-xexplicit}] [@b{-xauto}] [@b{-xdebug}]
348 @emph{Target IP2K options:}
349 [@b{-mip2022}|@b{-mip2022ext}]
353 @emph{Target M32R options:}
354 [@b{--m32rx}|@b{--[no-]warn-explicit-parallel-conflicts}|
359 @emph{Target M680X0 options:}
360 [@b{-l}] [@b{-m68000}|@b{-m68010}|@b{-m68020}|@dots{}]
364 @emph{Target M68HC11 options:}
365 [@b{-m68hc11}|@b{-m68hc12}]
366 [@b{-mshort}|@b{-mlong}]
367 [@b{-mshort-double}|@b{-mlong-double}]
368 [@b{--force-long-branchs}] [@b{--short-branchs}]
369 [@b{--strict-direct-mode}] [@b{--print-insn-syntax}]
370 [@b{--print-opcodes}] [@b{--generate-example}]
374 @emph{Target MCORE options:}
375 [@b{-jsri2bsr}] [@b{-sifilter}] [@b{-relax}]
376 [@b{-mcpu=[210|340]}]
380 @emph{Target MIPS options:}
381 [@b{-nocpp}] [@b{-EL}] [@b{-EB}] [@b{-n}] [@b{-O}[@var{optimization level}]]
382 [@b{-g}[@var{debug level}]] [@b{-G} @var{num}] [@b{-KPIC}] [@b{-call_shared}]
383 [@b{-non_shared}] [@b{-xgot}] [@b{--membedded-pic}]
384 [@b{-mabi}=@var{ABI}] [@b{-32}] [@b{-n32}] [@b{-64}] [@b{-mfp32}] [@b{-mgp32}]
385 [@b{-march}=@var{CPU}] [@b{-mtune}=@var{CPU}] [@b{-mips1}] [@b{-mips2}]
386 [@b{-mips3}] [@b{-mips4}] [@b{-mips5}] [@b{-mips32}] [@b{-mips64}]
387 [@b{-construct-floats}] [@b{-no-construct-floats}]
388 [@b{-trap}] [@b{-no-break}] [@b{-break}] [@b{-no-trap}]
389 [@b{-mfix7000}] [@b{-mno-fix7000}]
390 [@b{-mips16}] [@b{-no-mips16}]
391 [@b{-mips3d}] [@b{-no-mips3d}]
392 [@b{-mdmx}] [@b{-no-mdmx}]
393 [@b{-mdebug}] [@b{-no-mdebug}]
397 @emph{Target MMIX options:}
398 [@b{--fixed-special-register-names}] [@b{--globalize-symbols}]
399 [@b{--gnu-syntax}] [@b{--relax}] [@b{--no-predefined-symbols}]
400 [@b{--no-expand}] [@b{--no-merge-gregs}] [@b{-x}]
401 [@b{--linker-allocated-gregs}]
405 @emph{Target PDP11 options:}
406 [@b{-mpic}|@b{-mno-pic}] [@b{-mall}] [@b{-mno-extensions}]
407 [@b{-m}@var{extension}|@b{-mno-}@var{extension}]
408 [@b{-m}@var{cpu}] [@b{-m}@var{machine}]
412 @emph{Target picoJava options:}
417 @emph{Target PowerPC options:}
418 [@b{-mpwrx}|@b{-mpwr2}|@b{-mpwr}|@b{-m601}|@b{-mppc}|@b{-mppc32}|@b{-m603}|@b{-m604}|
419 @b{-m403}|@b{-m405}|@b{-mppc64}|@b{-m620}|@b{-mppc64bridge}|@b{-mbooke}|
420 @b{-mbooke32}|@b{-mbooke64}]
421 [@b{-mcom}|@b{-many}|@b{-maltivec}] [@b{-memb}]
422 [@b{-mregnames}|@b{-mno-regnames}]
423 [@b{-mrelocatable}|@b{-mrelocatable-lib}]
424 [@b{-mlittle}|@b{-mlittle-endian}|@b{-mbig}|@b{-mbig-endian}]
425 [@b{-msolaris}|@b{-mno-solaris}]
429 @emph{Target SPARC options:}
430 @c The order here is important. See c-sparc.texi.
431 [@b{-Av6}|@b{-Av7}|@b{-Av8}|@b{-Asparclet}|@b{-Asparclite}
432 @b{-Av8plus}|@b{-Av8plusa}|@b{-Av9}|@b{-Av9a}]
433 [@b{-xarch=v8plus}|@b{-xarch=v8plusa}] [@b{-bump}]
438 @emph{Target TIC54X options:}
439 [@b{-mcpu=54[123589]}|@b{-mcpu=54[56]lp}] [@b{-mfar-mode}|@b{-mf}]
440 [@b{-merrors-to-file} @var{<filename>}|@b{-me} @var{<filename>}]
443 @c Z8000 has no machine-dependent assembler options
452 Turn on listings, in any of a variety of ways:
456 omit false conditionals
459 omit debugging directives
462 include high-level source
468 include macro expansions
471 omit forms processing
477 set the name of the listing file
480 You may combine these options; for example, use @samp{-aln} for assembly
481 listing without forms processing. The @samp{=file} option, if used, must be
482 the last one. By itself, @samp{-a} defaults to @samp{-ahls}.
485 Ignored. This option is accepted for script compatibility with calls to
488 @item --defsym @var{sym}=@var{value}
489 Define the symbol @var{sym} to be @var{value} before assembling the input file.
490 @var{value} must be an integer constant. As in C, a leading @samp{0x}
491 indicates a hexadecimal value, and a leading @samp{0} indicates an octal value.
494 ``fast''---skip whitespace and comment preprocessing (assume source is
498 Generate stabs debugging information for each assembler line. This
499 may help debugging assembler code, if the debugger can handle it.
502 Generate DWARF2 debugging information for each assembler line. This
503 may help debugging assembler code, if the debugger can handle it. Note - this
504 option is only supported by some targets, not all of them.
507 Print a summary of the command line options and exit.
510 Print a summary of all target specific options and exit.
513 Add directory @var{dir} to the search list for @code{.include} directives.
516 Don't warn about signed overflow.
519 @ifclear DIFF-TBL-KLUGE
520 This option is accepted but has no effect on the @value{TARGET} family.
522 @ifset DIFF-TBL-KLUGE
523 Issue warnings when difference tables altered for long displacements.
528 Keep (in the symbol table) local symbols. On traditional a.out systems
529 these start with @samp{L}, but different systems have different local
532 @item --listing-lhs-width=@var{number}
533 Set the maximum width, in words, of the output data column for an assembler
534 listing to @var{number}.
536 @item --listing-lhs-width2=@var{number}
537 Set the maximum width, in words, of the output data column for continuation
538 lines in an assembler listing to @var{number}.
540 @item --listing-rhs-width=@var{number}
541 Set the maximum width of an input source line, as displayed in a listing, to
544 @item --listing-cont-lines=@var{number}
545 Set the maximum number of lines printed in a listing for a single line of input
548 @item -o @var{objfile}
549 Name the object-file output from @command{@value{AS}} @var{objfile}.
552 Fold the data section into the text section.
555 Print the maximum space (in bytes) and total time (in seconds) used by
558 @item --strip-local-absolute
559 Remove local absolute symbols from the outgoing symbol table.
563 Print the @command{as} version.
566 Print the @command{as} version and exit.
570 Suppress warning messages.
572 @item --fatal-warnings
573 Treat warnings as errors.
576 Don't suppress warning messages or treat them as errors.
585 Generate an object file even after errors.
587 @item -- | @var{files} @dots{}
588 Standard input, or source files to assemble.
593 The following options are available when @value{AS} is configured for
598 This option selects the core processor variant.
600 Select either big-endian (-EB) or little-endian (-EL) output.
605 The following options are available when @value{AS} is configured for the ARM
609 @item -mcpu=@var{processor}[+@var{extension}@dots{}]
610 Specify which ARM processor variant is the target.
611 @item -march=@var{architecture}[+@var{extension}@dots{}]
612 Specify which ARM architecture variant is used by the target.
613 @item -mfpu=@var{floating-point-format}
614 Select which Floating Point architecture is the target.
616 Enable Thumb only instruction decoding.
617 @item -mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant | -moabi
618 Select which procedure calling convention is in use.
620 Select either big-endian (-EB) or little-endian (-EL) output.
621 @item -mthumb-interwork
622 Specify that the code has been generated with interworking between Thumb and
625 Specify that PIC code has been generated.
630 See the info pages for documentation of the CRIS-specific options.
634 The following options are available when @value{AS} is configured for
637 @cindex D10V optimization
638 @cindex optimization, D10V
640 Optimize output by parallelizing instructions.
645 The following options are available when @value{AS} is configured for a D30V
648 @cindex D30V optimization
649 @cindex optimization, D30V
651 Optimize output by parallelizing instructions.
655 Warn when nops are generated.
657 @cindex D30V nops after 32-bit multiply
659 Warn when a nop after a 32-bit multiply instruction is generated.
664 The following options are available when @value{AS} is configured for the
665 Intel 80960 processor.
668 @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
669 Specify which variant of the 960 architecture is the target.
672 Add code to collect statistics about branches taken.
675 Do not alter compare-and-branch instructions for long displacements;
682 The following options are available when @value{AS} is configured for the
688 Specifies that the extended IP2022 instructions are allowed.
691 Restores the default behaviour, which restricts the permitted instructions to
692 just the basic IP2022 ones.
698 The following options are available when @value{AS} is configured for the
699 Mitsubishi M32R series.
704 Specify which processor in the M32R family is the target. The default
705 is normally the M32R, but this option changes it to the M32RX.
707 @item --warn-explicit-parallel-conflicts or --Wp
708 Produce warning messages when questionable parallel constructs are
711 @item --no-warn-explicit-parallel-conflicts or --Wnp
712 Do not produce warning messages when questionable parallel constructs are
719 The following options are available when @value{AS} is configured for the
720 Motorola 68000 series.
725 Shorten references to undefined symbols, to one word instead of two.
727 @item -m68000 | -m68008 | -m68010 | -m68020 | -m68030
728 @itemx | -m68040 | -m68060 | -m68302 | -m68331 | -m68332
729 @itemx | -m68333 | -m68340 | -mcpu32 | -m5200
730 Specify what processor in the 68000 family is the target. The default
731 is normally the 68020, but this can be changed at configuration time.
733 @item -m68881 | -m68882 | -mno-68881 | -mno-68882
734 The target machine does (or does not) have a floating-point coprocessor.
735 The default is to assume a coprocessor for 68020, 68030, and cpu32. Although
736 the basic 68000 is not compatible with the 68881, a combination of the
737 two can be specified, since it's possible to do emulation of the
738 coprocessor instructions with the main processor.
740 @item -m68851 | -mno-68851
741 The target machine does (or does not) have a memory-management
742 unit coprocessor. The default is to assume an MMU for 68020 and up.
749 For details about the PDP-11 machine dependent features options,
750 see @ref{PDP-11-Options}.
753 @item -mpic | -mno-pic
754 Generate position-independent (or position-dependent) code. The
755 default is @option{-mpic}.
758 @itemx -mall-extensions
759 Enable all instruction set extensions. This is the default.
761 @item -mno-extensions
762 Disable all instruction set extensions.
764 @item -m@var{extension} | -mno-@var{extension}
765 Enable (or disable) a particular instruction set extension.
768 Enable the instruction set extensions supported by a particular CPU, and
769 disable all other extensions.
771 @item -m@var{machine}
772 Enable the instruction set extensions supported by a particular machine
773 model, and disable all other extensions.
779 The following options are available when @value{AS} is configured for
780 a picoJava processor.
784 @cindex PJ endianness
785 @cindex endianness, PJ
786 @cindex big endian output, PJ
788 Generate ``big endian'' format output.
790 @cindex little endian output, PJ
792 Generate ``little endian'' format output.
798 The following options are available when @value{AS} is configured for the
799 Motorola 68HC11 or 68HC12 series.
803 @item -m68hc11 | -m68hc12
804 Specify what processor is the target. The default is
805 defined by the configuration option when building the assembler.
808 Specify to use the 16-bit integer ABI.
811 Specify to use the 32-bit integer ABI.
814 Specify to use the 32-bit double ABI.
817 Specify to use the 64-bit double ABI.
819 @item --force-long-branchs
820 Relative branches are turned into absolute ones. This concerns
821 conditional branches, unconditional branches and branches to a
824 @item -S | --short-branchs
825 Do not turn relative branchs into absolute ones
826 when the offset is out of range.
828 @item --strict-direct-mode
829 Do not turn the direct addressing mode into extended addressing mode
830 when the instruction does not support direct addressing mode.
832 @item --print-insn-syntax
833 Print the syntax of instruction in case of error.
835 @item --print-opcodes
836 print the list of instructions with syntax and then exit.
838 @item --generate-example
839 print an example of instruction for each possible instruction and then exit.
840 This option is only useful for testing @command{@value{AS}}.
846 The following options are available when @command{@value{AS}} is configured
847 for the SPARC architecture:
850 @item -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite
851 @itemx -Av8plus | -Av8plusa | -Av9 | -Av9a
852 Explicitly select a variant of the SPARC architecture.
854 @samp{-Av8plus} and @samp{-Av8plusa} select a 32 bit environment.
855 @samp{-Av9} and @samp{-Av9a} select a 64 bit environment.
857 @samp{-Av8plusa} and @samp{-Av9a} enable the SPARC V9 instruction set with
858 UltraSPARC extensions.
860 @item -xarch=v8plus | -xarch=v8plusa
861 For compatibility with the Solaris v9 assembler. These options are
862 equivalent to -Av8plus and -Av8plusa, respectively.
865 Warn when the assembler switches to another architecture.
870 The following options are available when @value{AS} is configured for the 'c54x
875 Enable extended addressing mode. All addresses and relocations will assume
876 extended addressing (usually 23 bits).
877 @item -mcpu=@var{CPU_VERSION}
878 Sets the CPU version being compiled for.
879 @item -merrors-to-file @var{FILENAME}
880 Redirect error output to a file, for broken systems which don't support such
881 behaviour in the shell.
886 The following options are available when @value{AS} is configured for
887 a @sc{mips} processor.
891 This option sets the largest size of an object that can be referenced
892 implicitly with the @code{gp} register. It is only accepted for targets that
893 use ECOFF format, such as a DECstation running Ultrix. The default value is 8.
895 @cindex MIPS endianness
896 @cindex endianness, MIPS
897 @cindex big endian output, MIPS
899 Generate ``big endian'' format output.
901 @cindex little endian output, MIPS
903 Generate ``little endian'' format output.
913 Generate code for a particular @sc{mips} Instruction Set Architecture level.
914 @samp{-mips1} is an alias for @samp{-march=r3000}, @samp{-mips2} is an
915 alias for @samp{-march=r6000}, @samp{-mips3} is an alias for
916 @samp{-march=r4000} and @samp{-mips4} is an alias for @samp{-march=r8000}.
917 @samp{-mips5}, @samp{-mips32}, and @samp{-mips64} correspond to generic
918 @samp{MIPS V}, @samp{MIPS32}, and @samp{MIPS64} ISA processors,
921 @item -march=@var{CPU}
922 Generate code for a particular @sc{mips} cpu.
924 @item -mtune=@var{cpu}
925 Schedule and tune for a particular @sc{mips} cpu.
929 Cause nops to be inserted if the read of the destination register
930 of an mfhi or mflo instruction occurs in the following two instructions.
934 Cause stabs-style debugging output to go into an ECOFF-style .mdebug
935 section instead of the standard ELF .stabs sections.
939 The register sizes are normally inferred from the ISA and ABI, but these
940 flags force a certain group of registers to be treated as 32 bits wide at
941 all times. @samp{-mgp32} controls the size of general-purpose registers
942 and @samp{-mfp32} controls the size of floating-point registers.
946 Generate code for the MIPS 16 processor. This is equivalent to putting
947 @code{.set mips16} at the start of the assembly file. @samp{-no-mips16}
948 turns off this option.
952 Generate code for the MIPS-3D Application Specific Extension.
953 This tells the assembler to accept MIPS-3D instructions.
954 @samp{-no-mips3d} turns off this option.
958 Generate code for the MDMX Application Specific Extension.
959 This tells the assembler to accept MDMX instructions.
960 @samp{-no-mdmx} turns off this option.
962 @item --construct-floats
963 @itemx --no-construct-floats
964 The @samp{--no-construct-floats} option disables the construction of
965 double width floating point constants by loading the two halves of the
966 value into the two single width floating point registers that make up
967 the double width register. By default @samp{--construct-floats} is
968 selected, allowing construction of these floating point constants.
971 @item --emulation=@var{name}
972 This option causes @command{@value{AS}} to emulate @command{@value{AS}} configured
973 for some other target, in all respects, including output format (choosing
974 between ELF and ECOFF only), handling of pseudo-opcodes which may generate
975 debugging information or store symbol table information, and default
976 endianness. The available configuration names are: @samp{mipsecoff},
977 @samp{mipself}, @samp{mipslecoff}, @samp{mipsbecoff}, @samp{mipslelf},
978 @samp{mipsbelf}. The first two do not alter the default endianness from that
979 of the primary target for which the assembler was configured; the others change
980 the default to little- or big-endian as indicated by the @samp{b} or @samp{l}
981 in the name. Using @samp{-EB} or @samp{-EL} will override the endianness
982 selection in any case.
984 This option is currently supported only when the primary target
985 @command{@value{AS}} is configured for is a @sc{mips} ELF or ECOFF target.
986 Furthermore, the primary target or others specified with
987 @samp{--enable-targets=@dots{}} at configuration time must include support for
988 the other format, if both are to be available. For example, the Irix 5
989 configuration includes support for both.
991 Eventually, this option will support more configurations, with more
992 fine-grained control over the assembler's behavior, and will be supported for
996 @command{@value{AS}} ignores this option. It is accepted for compatibility with
1003 Control how to deal with multiplication overflow and division by zero.
1004 @samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception
1005 (and only work for Instruction Set Architecture level 2 and higher);
1006 @samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a
1010 When this option is used, @command{@value{AS}} will issue a warning every
1011 time it generates a nop instruction from a macro.
1016 The following options are available when @value{AS} is configured for
1022 Enable or disable the JSRI to BSR transformation. By default this is enabled.
1023 The command line option @samp{-nojsri2bsr} can be used to disable it.
1027 Enable or disable the silicon filter behaviour. By default this is disabled.
1028 The default can be overridden by the @samp{-sifilter} command line option.
1031 Alter jump instructions for long displacements.
1033 @item -mcpu=[210|340]
1034 Select the cpu type on the target hardware. This controls which instructions
1038 Assemble for a big endian target.
1041 Assemble for a little endian target.
1047 See the info pages for documentation of the MMIX-specific options.
1053 * Manual:: Structure of this Manual
1054 * GNU Assembler:: The GNU Assembler
1055 * Object Formats:: Object File Formats
1056 * Command Line:: Command Line
1057 * Input Files:: Input Files
1058 * Object:: Output (Object) File
1059 * Errors:: Error and Warning Messages
1063 @section Structure of this Manual
1065 @cindex manual, structure and purpose
1066 This manual is intended to describe what you need to know to use
1067 @sc{gnu} @command{@value{AS}}. We cover the syntax expected in source files, including
1068 notation for symbols, constants, and expressions; the directives that
1069 @command{@value{AS}} understands; and of course how to invoke @command{@value{AS}}.
1072 We also cover special features in the @value{TARGET}
1073 configuration of @command{@value{AS}}, including assembler directives.
1076 This manual also describes some of the machine-dependent features of
1077 various flavors of the assembler.
1080 @cindex machine instructions (not covered)
1081 On the other hand, this manual is @emph{not} intended as an introduction
1082 to programming in assembly language---let alone programming in general!
1083 In a similar vein, we make no attempt to introduce the machine
1084 architecture; we do @emph{not} describe the instruction set, standard
1085 mnemonics, registers or addressing modes that are standard to a
1086 particular architecture.
1088 You may want to consult the manufacturer's
1089 machine architecture manual for this information.
1093 For information on the H8/300 machine instruction set, see @cite{H8/300
1094 Series Programming Manual} (Hitachi ADE--602--025). For the H8/300H,
1095 see @cite{H8/300H Series Programming Manual} (Hitachi).
1098 For information on the H8/500 machine instruction set, see @cite{H8/500
1099 Series Programming Manual} (Hitachi M21T001).
1102 For information on the Hitachi SH machine instruction set, see
1103 @cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.).
1106 For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual}
1110 @c I think this is premature---doc@cygnus.com, 17jan1991
1112 Throughout this manual, we assume that you are running @dfn{GNU},
1113 the portable operating system from the @dfn{Free Software
1114 Foundation, Inc.}. This restricts our attention to certain kinds of
1115 computer (in particular, the kinds of computers that @sc{gnu} can run on);
1116 once this assumption is granted examples and definitions need less
1119 @command{@value{AS}} is part of a team of programs that turn a high-level
1120 human-readable series of instructions into a low-level
1121 computer-readable series of instructions. Different versions of
1122 @command{@value{AS}} are used for different kinds of computer.
1125 @c There used to be a section "Terminology" here, which defined
1126 @c "contents", "byte", "word", and "long". Defining "word" to any
1127 @c particular size is confusing when the .word directive may generate 16
1128 @c bits on one machine and 32 bits on another; in general, for the user
1129 @c version of this manual, none of these terms seem essential to define.
1130 @c They were used very little even in the former draft of the manual;
1131 @c this draft makes an effort to avoid them (except in names of
1135 @section The GNU Assembler
1137 @c man begin DESCRIPTION
1139 @sc{gnu} @command{as} is really a family of assemblers.
1141 This manual describes @command{@value{AS}}, a member of that family which is
1142 configured for the @value{TARGET} architectures.
1144 If you use (or have used) the @sc{gnu} assembler on one architecture, you
1145 should find a fairly similar environment when you use it on another
1146 architecture. Each version has much in common with the others,
1147 including object file formats, most assembler directives (often called
1148 @dfn{pseudo-ops}) and assembler syntax.@refill
1150 @cindex purpose of @sc{gnu} assembler
1151 @command{@value{AS}} is primarily intended to assemble the output of the
1152 @sc{gnu} C compiler @code{@value{GCC}} for use by the linker
1153 @code{@value{LD}}. Nevertheless, we've tried to make @command{@value{AS}}
1154 assemble correctly everything that other assemblers for the same
1155 machine would assemble.
1157 Any exceptions are documented explicitly (@pxref{Machine Dependencies}).
1160 @c This remark should appear in generic version of manual; assumption
1161 @c here is that generic version sets M680x0.
1162 This doesn't mean @command{@value{AS}} always uses the same syntax as another
1163 assembler for the same architecture; for example, we know of several
1164 incompatible versions of 680x0 assembly language syntax.
1169 Unlike older assemblers, @command{@value{AS}} is designed to assemble a source
1170 program in one pass of the source file. This has a subtle impact on the
1171 @kbd{.org} directive (@pxref{Org,,@code{.org}}).
1173 @node Object Formats
1174 @section Object File Formats
1176 @cindex object file format
1177 The @sc{gnu} assembler can be configured to produce several alternative
1178 object file formats. For the most part, this does not affect how you
1179 write assembly language programs; but directives for debugging symbols
1180 are typically different in different file formats. @xref{Symbol
1181 Attributes,,Symbol Attributes}.
1184 On the @value{TARGET}, @command{@value{AS}} is configured to produce
1185 @value{OBJ-NAME} format object files.
1187 @c The following should exhaust all configs that set MULTI-OBJ, ideally
1189 On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
1190 @code{a.out} or COFF format object files.
1193 On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
1194 @code{b.out} or COFF format object files.
1197 On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
1198 SOM or ELF format object files.
1203 @section Command Line
1205 @cindex command line conventions
1207 After the program name @command{@value{AS}}, the command line may contain
1208 options and file names. Options may appear in any order, and may be
1209 before, after, or between file names. The order of file names is
1212 @cindex standard input, as input file
1214 @file{--} (two hyphens) by itself names the standard input file
1215 explicitly, as one of the files for @command{@value{AS}} to assemble.
1217 @cindex options, command line
1218 Except for @samp{--} any command line argument that begins with a
1219 hyphen (@samp{-}) is an option. Each option changes the behavior of
1220 @command{@value{AS}}. No option changes the way another option works. An
1221 option is a @samp{-} followed by one or more letters; the case of
1222 the letter is important. All options are optional.
1224 Some options expect exactly one file name to follow them. The file
1225 name may either immediately follow the option's letter (compatible
1226 with older assemblers) or it may be the next command argument (@sc{gnu}
1227 standard). These two command lines are equivalent:
1230 @value{AS} -o my-object-file.o mumble.s
1231 @value{AS} -omy-object-file.o mumble.s
1235 @section Input Files
1238 @cindex source program
1239 @cindex files, input
1240 We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
1241 describe the program input to one run of @command{@value{AS}}. The program may
1242 be in one or more files; how the source is partitioned into files
1243 doesn't change the meaning of the source.
1245 @c I added "con" prefix to "catenation" just to prove I can overcome my
1246 @c APL training... doc@cygnus.com
1247 The source program is a concatenation of the text in all the files, in the
1250 @c man begin DESCRIPTION
1251 Each time you run @command{@value{AS}} it assembles exactly one source
1252 program. The source program is made up of one or more files.
1253 (The standard input is also a file.)
1255 You give @command{@value{AS}} a command line that has zero or more input file
1256 names. The input files are read (from left file name to right). A
1257 command line argument (in any position) that has no special meaning
1258 is taken to be an input file name.
1260 If you give @command{@value{AS}} no file names it attempts to read one input file
1261 from the @command{@value{AS}} standard input, which is normally your terminal. You
1262 may have to type @key{ctl-D} to tell @command{@value{AS}} there is no more program
1265 Use @samp{--} if you need to explicitly name the standard input file
1266 in your command line.
1268 If the source is empty, @command{@value{AS}} produces a small, empty object
1273 @subheading Filenames and Line-numbers
1275 @cindex input file linenumbers
1276 @cindex line numbers, in input files
1277 There are two ways of locating a line in the input file (or files) and
1278 either may be used in reporting error messages. One way refers to a line
1279 number in a physical file; the other refers to a line number in a
1280 ``logical'' file. @xref{Errors, ,Error and Warning Messages}.
1282 @dfn{Physical files} are those files named in the command line given
1283 to @command{@value{AS}}.
1285 @dfn{Logical files} are simply names declared explicitly by assembler
1286 directives; they bear no relation to physical files. Logical file names help
1287 error messages reflect the original source file, when @command{@value{AS}} source
1288 is itself synthesized from other files. @command{@value{AS}} understands the
1289 @samp{#} directives emitted by the @code{@value{GCC}} preprocessor. See also
1290 @ref{File,,@code{.file}}.
1293 @section Output (Object) File
1299 Every time you run @command{@value{AS}} it produces an output file, which is
1300 your assembly language program translated into numbers. This file
1301 is the object file. Its default name is
1309 @code{b.out} when @command{@value{AS}} is configured for the Intel 80960.
1311 You can give it another name by using the @option{-o} option. Conventionally,
1312 object file names end with @file{.o}. The default name is used for historical
1313 reasons: older assemblers were capable of assembling self-contained programs
1314 directly into a runnable program. (For some formats, this isn't currently
1315 possible, but it can be done for the @code{a.out} format.)
1319 The object file is meant for input to the linker @code{@value{LD}}. It contains
1320 assembled program code, information to help @code{@value{LD}} integrate
1321 the assembled program into a runnable file, and (optionally) symbolic
1322 information for the debugger.
1324 @c link above to some info file(s) like the description of a.out.
1325 @c don't forget to describe @sc{gnu} info as well as Unix lossage.
1328 @section Error and Warning Messages
1330 @c man begin DESCRIPTION
1332 @cindex error messages
1333 @cindex warning messages
1334 @cindex messages from assembler
1335 @command{@value{AS}} may write warnings and error messages to the standard error
1336 file (usually your terminal). This should not happen when a compiler
1337 runs @command{@value{AS}} automatically. Warnings report an assumption made so
1338 that @command{@value{AS}} could keep assembling a flawed program; errors report a
1339 grave problem that stops the assembly.
1343 @cindex format of warning messages
1344 Warning messages have the format
1347 file_name:@b{NNN}:Warning Message Text
1351 @cindex line numbers, in warnings/errors
1352 (where @b{NNN} is a line number). If a logical file name has been given
1353 (@pxref{File,,@code{.file}}) it is used for the filename, otherwise the name of
1354 the current input file is used. If a logical line number was given
1356 (@pxref{Line,,@code{.line}})
1360 (@pxref{Line,,@code{.line}})
1363 (@pxref{Ln,,@code{.ln}})
1366 then it is used to calculate the number printed,
1367 otherwise the actual line in the current source file is printed. The
1368 message text is intended to be self explanatory (in the grand Unix
1371 @cindex format of error messages
1372 Error messages have the format
1374 file_name:@b{NNN}:FATAL:Error Message Text
1376 The file name and line number are derived as for warning
1377 messages. The actual message text may be rather less explanatory
1378 because many of them aren't supposed to happen.
1381 @chapter Command-Line Options
1383 @cindex options, all versions of assembler
1384 This chapter describes command-line options available in @emph{all}
1385 versions of the @sc{gnu} assembler; @pxref{Machine Dependencies}, for options specific
1387 to the @value{TARGET}.
1390 to particular machine architectures.
1393 @c man begin DESCRIPTION
1395 If you are invoking @command{@value{AS}} via the @sc{gnu} C compiler (version 2),
1396 you can use the @samp{-Wa} option to pass arguments through to the assembler.
1397 The assembler arguments must be separated from each other (and the @samp{-Wa})
1398 by commas. For example:
1401 gcc -c -g -O -Wa,-alh,-L file.c
1405 This passes two options to the assembler: @samp{-alh} (emit a listing to
1406 standard output with with high-level and assembly source) and @samp{-L} (retain
1407 local symbols in the symbol table).
1409 Usually you do not need to use this @samp{-Wa} mechanism, since many compiler
1410 command-line options are automatically passed to the assembler by the compiler.
1411 (You can call the @sc{gnu} compiler driver with the @samp{-v} option to see
1412 precisely what options it passes to each compilation pass, including the
1418 * a:: -a[cdhlns] enable listings
1419 * D:: -D for compatibility
1420 * f:: -f to work faster
1421 * I:: -I for .include search path
1422 @ifclear DIFF-TBL-KLUGE
1423 * K:: -K for compatibility
1425 @ifset DIFF-TBL-KLUGE
1426 * K:: -K for difference tables
1429 * L:: -L to retain local labels
1430 * listing:: --listing-XXX to configure listing output
1431 * M:: -M or --mri to assemble in MRI compatibility mode
1432 * MD:: --MD for dependency tracking
1433 * o:: -o to name the object file
1434 * R:: -R to join data and text sections
1435 * statistics:: --statistics to see statistics about assembly
1436 * traditional-format:: --traditional-format for compatible output
1437 * v:: -v to announce version
1438 * W:: -W, --no-warn, --warn, --fatal-warnings to control warnings
1439 * Z:: -Z to make object file even after errors
1443 @section Enable Listings: @option{-a[cdhlns]}
1452 @cindex listings, enabling
1453 @cindex assembly listings, enabling
1455 These options enable listing output from the assembler. By itself,
1456 @samp{-a} requests high-level, assembly, and symbols listing.
1457 You can use other letters to select specific options for the list:
1458 @samp{-ah} requests a high-level language listing,
1459 @samp{-al} requests an output-program assembly listing, and
1460 @samp{-as} requests a symbol table listing.
1461 High-level listings require that a compiler debugging option like
1462 @samp{-g} be used, and that assembly listings (@samp{-al}) be requested
1465 Use the @samp{-ac} option to omit false conditionals from a listing. Any lines
1466 which are not assembled because of a false @code{.if} (or @code{.ifdef}, or any
1467 other conditional), or a true @code{.if} followed by an @code{.else}, will be
1468 omitted from the listing.
1470 Use the @samp{-ad} option to omit debugging directives from the
1473 Once you have specified one of these options, you can further control
1474 listing output and its appearance using the directives @code{.list},
1475 @code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
1477 The @samp{-an} option turns off all forms processing.
1478 If you do not request listing output with one of the @samp{-a} options, the
1479 listing-control directives have no effect.
1481 The letters after @samp{-a} may be combined into one option,
1482 @emph{e.g.}, @samp{-aln}.
1484 Note if the assembler source is coming from the standard input (eg because it
1485 is being created by @code{@value{GCC}} and the @samp{-pipe} command line switch
1486 is being used) then the listing will not contain any comments or preprocessor
1487 directives. This is because the listing code buffers input source lines from
1488 stdin only after they have been preprocessed by the assembler. This reduces
1489 memory usage and makes the code more efficient.
1492 @section @option{-D}
1495 This option has no effect whatsoever, but it is accepted to make it more
1496 likely that scripts written for other assemblers also work with
1497 @command{@value{AS}}.
1500 @section Work Faster: @option{-f}
1503 @cindex trusted compiler
1504 @cindex faster processing (@option{-f})
1505 @samp{-f} should only be used when assembling programs written by a
1506 (trusted) compiler. @samp{-f} stops the assembler from doing whitespace
1507 and comment preprocessing on
1508 the input file(s) before assembling them. @xref{Preprocessing,
1512 @emph{Warning:} if you use @samp{-f} when the files actually need to be
1513 preprocessed (if they contain comments, for example), @command{@value{AS}} does
1518 @section @code{.include} search path: @option{-I} @var{path}
1520 @kindex -I @var{path}
1521 @cindex paths for @code{.include}
1522 @cindex search path for @code{.include}
1523 @cindex @code{include} directive search path
1524 Use this option to add a @var{path} to the list of directories
1525 @command{@value{AS}} searches for files specified in @code{.include}
1526 directives (@pxref{Include,,@code{.include}}). You may use @option{-I} as
1527 many times as necessary to include a variety of paths. The current
1528 working directory is always searched first; after that, @command{@value{AS}}
1529 searches any @samp{-I} directories in the same order as they were
1530 specified (left to right) on the command line.
1533 @section Difference Tables: @option{-K}
1536 @ifclear DIFF-TBL-KLUGE
1537 On the @value{TARGET} family, this option is allowed, but has no effect. It is
1538 permitted for compatibility with the @sc{gnu} assembler on other platforms,
1539 where it can be used to warn when the assembler alters the machine code
1540 generated for @samp{.word} directives in difference tables. The @value{TARGET}
1541 family does not have the addressing limitations that sometimes lead to this
1542 alteration on other platforms.
1545 @ifset DIFF-TBL-KLUGE
1546 @cindex difference tables, warning
1547 @cindex warning for altered difference tables
1548 @command{@value{AS}} sometimes alters the code emitted for directives of the form
1549 @samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}.
1550 You can use the @samp{-K} option if you want a warning issued when this
1555 @section Include Local Labels: @option{-L}
1558 @cindex local labels, retaining in output
1559 Labels beginning with @samp{L} (upper case only) are called @dfn{local
1560 labels}. @xref{Symbol Names}. Normally you do not see such labels when
1561 debugging, because they are intended for the use of programs (like
1562 compilers) that compose assembler programs, not for your notice.
1563 Normally both @command{@value{AS}} and @code{@value{LD}} discard such labels, so you do not
1564 normally debug with them.
1566 This option tells @command{@value{AS}} to retain those @samp{L@dots{}} symbols
1567 in the object file. Usually if you do this you also tell the linker
1568 @code{@value{LD}} to preserve symbols whose names begin with @samp{L}.
1570 By default, a local label is any label beginning with @samp{L}, but each
1571 target is allowed to redefine the local label prefix.
1573 On the HPPA local labels begin with @samp{L$}.
1577 @section Configuring listing output: @option{--listing}
1579 The listing feature of the assembler can be enabled via the command line switch
1580 @samp{-a} (@pxref{a}). This feature combines the input source file(s) with a
1581 hex dump of the corresponding locations in the output object file, and displays
1582 them as a listing file. The format of this listing can be controlled by pseudo
1583 ops inside the assembler source (@pxref{List} @pxref{Title} @pxref{Sbttl}
1584 @pxref{Psize} @pxref{Eject}) and also by the following switches:
1587 @item --listing-lhs-width=@samp{number}
1588 @kindex --listing-lhs-width
1589 @cindex Width of first line disassembly output
1590 Sets the maximum width, in words, of the first line of the hex byte dump. This
1591 dump appears on the left hand side of the listing output.
1593 @item --listing-lhs-width2=@samp{number}
1594 @kindex --listing-lhs-width2
1595 @cindex Width of continuation lines of disassembly output
1596 Sets the maximum width, in words, of any further lines of the hex byte dump for
1597 a given input source line. If this value is not specified, it defaults to being
1598 the same as the value specified for @samp{--listing-lhs-width}. If neither
1599 switch is used the default is to one.
1601 @item --listing-rhs-width=@samp{number}
1602 @kindex --listing-rhs-width
1603 @cindex Width of source line output
1604 Sets the maximum width, in characters, of the source line that is displayed
1605 alongside the hex dump. The default value for this parameter is 100. The
1606 source line is displayed on the right hand side of the listing output.
1608 @item --listing-cont-lines=@samp{number}
1609 @kindex --listing-cont-lines
1610 @cindex Maximum number of continuation lines
1611 Sets the maximum number of continuation lines of hex dump that will be
1612 displayed for a given single line of source input. The default value is 4.
1616 @section Assemble in MRI Compatibility Mode: @option{-M}
1619 @cindex MRI compatibility mode
1620 The @option{-M} or @option{--mri} option selects MRI compatibility mode. This
1621 changes the syntax and pseudo-op handling of @command{@value{AS}} to make it
1622 compatible with the @code{ASM68K} or the @code{ASM960} (depending upon the
1623 configured target) assembler from Microtec Research. The exact nature of the
1624 MRI syntax will not be documented here; see the MRI manuals for more
1625 information. Note in particular that the handling of macros and macro
1626 arguments is somewhat different. The purpose of this option is to permit
1627 assembling existing MRI assembler code using @command{@value{AS}}.
1629 The MRI compatibility is not complete. Certain operations of the MRI assembler
1630 depend upon its object file format, and can not be supported using other object
1631 file formats. Supporting these would require enhancing each object file format
1632 individually. These are:
1635 @item global symbols in common section
1637 The m68k MRI assembler supports common sections which are merged by the linker.
1638 Other object file formats do not support this. @command{@value{AS}} handles
1639 common sections by treating them as a single common symbol. It permits local
1640 symbols to be defined within a common section, but it can not support global
1641 symbols, since it has no way to describe them.
1643 @item complex relocations
1645 The MRI assemblers support relocations against a negated section address, and
1646 relocations which combine the start addresses of two or more sections. These
1647 are not support by other object file formats.
1649 @item @code{END} pseudo-op specifying start address
1651 The MRI @code{END} pseudo-op permits the specification of a start address.
1652 This is not supported by other object file formats. The start address may
1653 instead be specified using the @option{-e} option to the linker, or in a linker
1656 @item @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops
1658 The MRI @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops assign a module
1659 name to the output file. This is not supported by other object file formats.
1661 @item @code{ORG} pseudo-op
1663 The m68k MRI @code{ORG} pseudo-op begins an absolute section at a given
1664 address. This differs from the usual @command{@value{AS}} @code{.org} pseudo-op,
1665 which changes the location within the current section. Absolute sections are
1666 not supported by other object file formats. The address of a section may be
1667 assigned within a linker script.
1670 There are some other features of the MRI assembler which are not supported by
1671 @command{@value{AS}}, typically either because they are difficult or because they
1672 seem of little consequence. Some of these may be supported in future releases.
1676 @item EBCDIC strings
1678 EBCDIC strings are not supported.
1680 @item packed binary coded decimal
1682 Packed binary coded decimal is not supported. This means that the @code{DC.P}
1683 and @code{DCB.P} pseudo-ops are not supported.
1685 @item @code{FEQU} pseudo-op
1687 The m68k @code{FEQU} pseudo-op is not supported.
1689 @item @code{NOOBJ} pseudo-op
1691 The m68k @code{NOOBJ} pseudo-op is not supported.
1693 @item @code{OPT} branch control options
1695 The m68k @code{OPT} branch control options---@code{B}, @code{BRS}, @code{BRB},
1696 @code{BRL}, and @code{BRW}---are ignored. @command{@value{AS}} automatically
1697 relaxes all branches, whether forward or backward, to an appropriate size, so
1698 these options serve no purpose.
1700 @item @code{OPT} list control options
1702 The following m68k @code{OPT} list control options are ignored: @code{C},
1703 @code{CEX}, @code{CL}, @code{CRE}, @code{E}, @code{G}, @code{I}, @code{M},
1704 @code{MEX}, @code{MC}, @code{MD}, @code{X}.
1706 @item other @code{OPT} options
1708 The following m68k @code{OPT} options are ignored: @code{NEST}, @code{O},
1709 @code{OLD}, @code{OP}, @code{P}, @code{PCO}, @code{PCR}, @code{PCS}, @code{R}.
1711 @item @code{OPT} @code{D} option is default
1713 The m68k @code{OPT} @code{D} option is the default, unlike the MRI assembler.
1714 @code{OPT NOD} may be used to turn it off.
1716 @item @code{XREF} pseudo-op.
1718 The m68k @code{XREF} pseudo-op is ignored.
1720 @item @code{.debug} pseudo-op
1722 The i960 @code{.debug} pseudo-op is not supported.
1724 @item @code{.extended} pseudo-op
1726 The i960 @code{.extended} pseudo-op is not supported.
1728 @item @code{.list} pseudo-op.
1730 The various options of the i960 @code{.list} pseudo-op are not supported.
1732 @item @code{.optimize} pseudo-op
1734 The i960 @code{.optimize} pseudo-op is not supported.
1736 @item @code{.output} pseudo-op
1738 The i960 @code{.output} pseudo-op is not supported.
1740 @item @code{.setreal} pseudo-op
1742 The i960 @code{.setreal} pseudo-op is not supported.
1747 @section Dependency tracking: @option{--MD}
1750 @cindex dependency tracking
1753 @command{@value{AS}} can generate a dependency file for the file it creates. This
1754 file consists of a single rule suitable for @code{make} describing the
1755 dependencies of the main source file.
1757 The rule is written to the file named in its argument.
1759 This feature is used in the automatic updating of makefiles.
1762 @section Name the Object File: @option{-o}
1765 @cindex naming object file
1766 @cindex object file name
1767 There is always one object file output when you run @command{@value{AS}}. By
1768 default it has the name
1771 @file{a.out} (or @file{b.out}, for Intel 960 targets only).
1785 You use this option (which takes exactly one filename) to give the
1786 object file a different name.
1788 Whatever the object file is called, @command{@value{AS}} overwrites any
1789 existing file of the same name.
1792 @section Join Data and Text Sections: @option{-R}
1795 @cindex data and text sections, joining
1796 @cindex text and data sections, joining
1797 @cindex joining text and data sections
1798 @cindex merging text and data sections
1799 @option{-R} tells @command{@value{AS}} to write the object file as if all
1800 data-section data lives in the text section. This is only done at
1801 the very last moment: your binary data are the same, but data
1802 section parts are relocated differently. The data section part of
1803 your object file is zero bytes long because all its bytes are
1804 appended to the text section. (@xref{Sections,,Sections and Relocation}.)
1806 When you specify @option{-R} it would be possible to generate shorter
1807 address displacements (because we do not have to cross between text and
1808 data section). We refrain from doing this simply for compatibility with
1809 older versions of @command{@value{AS}}. In future, @option{-R} may work this way.
1812 When @command{@value{AS}} is configured for COFF output,
1813 this option is only useful if you use sections named @samp{.text} and
1818 @option{-R} is not supported for any of the HPPA targets. Using
1819 @option{-R} generates a warning from @command{@value{AS}}.
1823 @section Display Assembly Statistics: @option{--statistics}
1825 @kindex --statistics
1826 @cindex statistics, about assembly
1827 @cindex time, total for assembly
1828 @cindex space used, maximum for assembly
1829 Use @samp{--statistics} to display two statistics about the resources used by
1830 @command{@value{AS}}: the maximum amount of space allocated during the assembly
1831 (in bytes), and the total execution time taken for the assembly (in @sc{cpu}
1834 @node traditional-format
1835 @section Compatible output: @option{--traditional-format}
1837 @kindex --traditional-format
1838 For some targets, the output of @command{@value{AS}} is different in some ways
1839 from the output of some existing assembler. This switch requests
1840 @command{@value{AS}} to use the traditional format instead.
1842 For example, it disables the exception frame optimizations which
1843 @command{@value{AS}} normally does by default on @code{@value{GCC}} output.
1846 @section Announce Version: @option{-v}
1850 @cindex assembler version
1851 @cindex version of assembler
1852 You can find out what version of as is running by including the
1853 option @samp{-v} (which you can also spell as @samp{-version}) on the
1857 @section Control Warnings: @option{-W}, @option{--warn}, @option{--no-warn}, @option{--fatal-warnings}
1859 @command{@value{AS}} should never give a warning or error message when
1860 assembling compiler output. But programs written by people often
1861 cause @command{@value{AS}} to give a warning that a particular assumption was
1862 made. All such warnings are directed to the standard error file.
1865 @kindex @samp{--no-warn}
1866 @cindex suppressing warnings
1867 @cindex warnings, suppressing
1868 If you use the @option{-W} and @option{--no-warn} options, no warnings are issued.
1869 This only affects the warning messages: it does not change any particular of
1870 how @command{@value{AS}} assembles your file. Errors, which stop the assembly,
1873 @kindex @samp{--fatal-warnings}
1874 @cindex errors, caused by warnings
1875 @cindex warnings, causing error
1876 If you use the @option{--fatal-warnings} option, @command{@value{AS}} considers
1877 files that generate warnings to be in error.
1879 @kindex @samp{--warn}
1880 @cindex warnings, switching on
1881 You can switch these options off again by specifying @option{--warn}, which
1882 causes warnings to be output as usual.
1885 @section Generate Object File in Spite of Errors: @option{-Z}
1886 @cindex object file, after errors
1887 @cindex errors, continuing after
1888 After an error message, @command{@value{AS}} normally produces no output. If for
1889 some reason you are interested in object file output even after
1890 @command{@value{AS}} gives an error message on your program, use the @samp{-Z}
1891 option. If there are any errors, @command{@value{AS}} continues anyways, and
1892 writes an object file after a final warning message of the form @samp{@var{n}
1893 errors, @var{m} warnings, generating bad object file.}
1898 @cindex machine-independent syntax
1899 @cindex syntax, machine-independent
1900 This chapter describes the machine-independent syntax allowed in a
1901 source file. @command{@value{AS}} syntax is similar to what many other
1902 assemblers use; it is inspired by the BSD 4.2
1907 assembler, except that @command{@value{AS}} does not assemble Vax bit-fields.
1911 * Preprocessing:: Preprocessing
1912 * Whitespace:: Whitespace
1913 * Comments:: Comments
1914 * Symbol Intro:: Symbols
1915 * Statements:: Statements
1916 * Constants:: Constants
1920 @section Preprocessing
1922 @cindex preprocessing
1923 The @command{@value{AS}} internal preprocessor:
1925 @cindex whitespace, removed by preprocessor
1927 adjusts and removes extra whitespace. It leaves one space or tab before
1928 the keywords on a line, and turns any other whitespace on the line into
1931 @cindex comments, removed by preprocessor
1933 removes all comments, replacing them with a single space, or an
1934 appropriate number of newlines.
1936 @cindex constants, converted by preprocessor
1938 converts character constants into the appropriate numeric values.
1941 It does not do macro processing, include file handling, or
1942 anything else you may get from your C compiler's preprocessor. You can
1943 do include file processing with the @code{.include} directive
1944 (@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver
1945 to get other ``CPP'' style preprocessing, by giving the input file a
1946 @samp{.S} suffix. @xref{Overall Options,, Options Controlling the Kind of
1947 Output, gcc.info, Using GNU CC}.
1949 Excess whitespace, comments, and character constants
1950 cannot be used in the portions of the input text that are not
1953 @cindex turning preprocessing on and off
1954 @cindex preprocessing, turning on and off
1957 If the first line of an input file is @code{#NO_APP} or if you use the
1958 @samp{-f} option, whitespace and comments are not removed from the input file.
1959 Within an input file, you can ask for whitespace and comment removal in
1960 specific portions of the by putting a line that says @code{#APP} before the
1961 text that may contain whitespace or comments, and putting a line that says
1962 @code{#NO_APP} after this text. This feature is mainly intend to support
1963 @code{asm} statements in compilers whose output is otherwise free of comments
1970 @dfn{Whitespace} is one or more blanks or tabs, in any order.
1971 Whitespace is used to separate symbols, and to make programs neater for
1972 people to read. Unless within character constants
1973 (@pxref{Characters,,Character Constants}), any whitespace means the same
1974 as exactly one space.
1980 There are two ways of rendering comments to @command{@value{AS}}. In both
1981 cases the comment is equivalent to one space.
1983 Anything from @samp{/*} through the next @samp{*/} is a comment.
1984 This means you may not nest these comments.
1988 The only way to include a newline ('\n') in a comment
1989 is to use this sort of comment.
1992 /* This sort of comment does not nest. */
1995 @cindex line comment character
1996 Anything from the @dfn{line comment} character to the next newline
1997 is considered a comment and is ignored. The line comment character is
1999 @samp{;} for the AMD 29K family;
2002 @samp{;} on the ARC;
2005 @samp{@@} on the ARM;
2008 @samp{;} for the H8/300 family;
2011 @samp{!} for the H8/500 family;
2014 @samp{;} for the HPPA;
2017 @samp{#} on the i386 and x86-64;
2020 @samp{#} on the i960;
2023 @samp{;} for the PDP-11;
2026 @samp{;} for picoJava;
2029 @samp{;} for Motorola PowerPC;
2032 @samp{!} for the Hitachi SH;
2035 @samp{!} on the SPARC;
2038 @samp{#} on the ip2k;
2041 @samp{#} on the m32r;
2044 @samp{|} on the 680x0;
2047 @samp{#} on the 68HC11 and 68HC12;
2050 @samp{;} on the M880x0;
2053 @samp{#} on the Vax;
2056 @samp{!} for the Z8000;
2059 @samp{#} on the V850;
2061 see @ref{Machine Dependencies}. @refill
2062 @c FIXME What about i860?
2065 On some machines there are two different line comment characters. One
2066 character only begins a comment if it is the first non-whitespace character on
2067 a line, while the other always begins a comment.
2071 The V850 assembler also supports a double dash as starting a comment that
2072 extends to the end of the line.
2078 @cindex lines starting with @code{#}
2079 @cindex logical line numbers
2080 To be compatible with past assemblers, lines that begin with @samp{#} have a
2081 special interpretation. Following the @samp{#} should be an absolute
2082 expression (@pxref{Expressions}): the logical line number of the @emph{next}
2083 line. Then a string (@pxref{Strings,, Strings}) is allowed: if present it is a
2084 new logical file name. The rest of the line, if any, should be whitespace.
2086 If the first non-whitespace characters on the line are not numeric,
2087 the line is ignored. (Just like a comment.)
2090 # This is an ordinary comment.
2091 # 42-6 "new_file_name" # New logical file name
2092 # This is logical line # 36.
2094 This feature is deprecated, and may disappear from future versions
2095 of @command{@value{AS}}.
2100 @cindex characters used in symbols
2101 @ifclear SPECIAL-SYMS
2102 A @dfn{symbol} is one or more characters chosen from the set of all
2103 letters (both upper and lower case), digits and the three characters
2109 A @dfn{symbol} is one or more characters chosen from the set of all
2110 letters (both upper and lower case), digits and the three characters
2111 @samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in
2117 On most machines, you can also use @code{$} in symbol names; exceptions
2118 are noted in @ref{Machine Dependencies}.
2120 No symbol may begin with a digit. Case is significant.
2121 There is no length limit: all characters are significant. Symbols are
2122 delimited by characters not in that set, or by the beginning of a file
2123 (since the source program must end with a newline, the end of a file is
2124 not a possible symbol delimiter). @xref{Symbols}.
2125 @cindex length of symbols
2130 @cindex statements, structure of
2131 @cindex line separator character
2132 @cindex statement separator character
2134 @ifclear abnormal-separator
2135 A @dfn{statement} ends at a newline character (@samp{\n}) or at a
2136 semicolon (@samp{;}). The newline or semicolon is considered part of
2137 the preceding statement. Newlines and semicolons within character
2138 constants are an exception: they do not end statements.
2140 @ifset abnormal-separator
2142 A @dfn{statement} ends at a newline character (@samp{\n}) or an ``at''
2143 sign (@samp{@@}). The newline or at sign is considered part of the
2144 preceding statement. Newlines and at signs within character constants
2145 are an exception: they do not end statements.
2148 A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation
2149 point (@samp{!}). The newline or exclamation point is considered part of the
2150 preceding statement. Newlines and exclamation points within character
2151 constants are an exception: they do not end statements.
2154 A @dfn{statement} ends at a newline character (@samp{\n}); or (for the
2155 H8/300) a dollar sign (@samp{$}); or (for the
2158 (@samp{;}). The newline or separator character is considered part of
2159 the preceding statement. Newlines and separators within character
2160 constants are an exception: they do not end statements.
2165 A @dfn{statement} ends at a newline character (@samp{\n}) or line
2166 separator character. (The line separator is usually @samp{;}, unless
2167 this conflicts with the comment character; @pxref{Machine Dependencies}.) The
2168 newline or separator character is considered part of the preceding
2169 statement. Newlines and separators within character constants are an
2170 exception: they do not end statements.
2173 @cindex newline, required at file end
2174 @cindex EOF, newline must precede
2175 It is an error to end any statement with end-of-file: the last
2176 character of any input file should be a newline.@refill
2178 An empty statement is allowed, and may include whitespace. It is ignored.
2180 @cindex instructions and directives
2181 @cindex directives and instructions
2182 @c "key symbol" is not used elsewhere in the document; seems pedantic to
2183 @c @defn{} it in that case, as was done previously... doc@cygnus.com,
2185 A statement begins with zero or more labels, optionally followed by a
2186 key symbol which determines what kind of statement it is. The key
2187 symbol determines the syntax of the rest of the statement. If the
2188 symbol begins with a dot @samp{.} then the statement is an assembler
2189 directive: typically valid for any computer. If the symbol begins with
2190 a letter the statement is an assembly language @dfn{instruction}: it
2191 assembles into a machine language instruction.
2193 Different versions of @command{@value{AS}} for different computers
2194 recognize different instructions. In fact, the same symbol may
2195 represent a different instruction in a different computer's assembly
2199 @cindex @code{:} (label)
2200 @cindex label (@code{:})
2201 A label is a symbol immediately followed by a colon (@code{:}).
2202 Whitespace before a label or after a colon is permitted, but you may not
2203 have whitespace between a label's symbol and its colon. @xref{Labels}.
2206 For HPPA targets, labels need not be immediately followed by a colon, but
2207 the definition of a label must begin in column zero. This also implies that
2208 only one label may be defined on each line.
2212 label: .directive followed by something
2213 another_label: # This is an empty statement.
2214 instruction operand_1, operand_2, @dots{}
2221 A constant is a number, written so that its value is known by
2222 inspection, without knowing any context. Like this:
2225 .byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
2226 .ascii "Ring the bell\7" # A string constant.
2227 .octa 0x123456789abcdef0123456789ABCDEF0 # A bignum.
2228 .float 0f-314159265358979323846264338327\
2229 95028841971.693993751E-40 # - pi, a flonum.
2234 * Characters:: Character Constants
2235 * Numbers:: Number Constants
2239 @subsection Character Constants
2241 @cindex character constants
2242 @cindex constants, character
2243 There are two kinds of character constants. A @dfn{character} stands
2244 for one character in one byte and its value may be used in
2245 numeric expressions. String constants (properly called string
2246 @emph{literals}) are potentially many bytes and their values may not be
2247 used in arithmetic expressions.
2251 * Chars:: Characters
2255 @subsubsection Strings
2257 @cindex string constants
2258 @cindex constants, string
2259 A @dfn{string} is written between double-quotes. It may contain
2260 double-quotes or null characters. The way to get special characters
2261 into a string is to @dfn{escape} these characters: precede them with
2262 a backslash @samp{\} character. For example @samp{\\} represents
2263 one backslash: the first @code{\} is an escape which tells
2264 @command{@value{AS}} to interpret the second character literally as a backslash
2265 (which prevents @command{@value{AS}} from recognizing the second @code{\} as an
2266 escape character). The complete list of escapes follows.
2268 @cindex escape codes, character
2269 @cindex character escape codes
2272 @c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
2274 @cindex @code{\b} (backspace character)
2275 @cindex backspace (@code{\b})
2277 Mnemonic for backspace; for ASCII this is octal code 010.
2280 @c Mnemonic for EOText; for ASCII this is octal code 004.
2282 @cindex @code{\f} (formfeed character)
2283 @cindex formfeed (@code{\f})
2285 Mnemonic for FormFeed; for ASCII this is octal code 014.
2287 @cindex @code{\n} (newline character)
2288 @cindex newline (@code{\n})
2290 Mnemonic for newline; for ASCII this is octal code 012.
2293 @c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
2295 @cindex @code{\r} (carriage return character)
2296 @cindex carriage return (@code{\r})
2298 Mnemonic for carriage-Return; for ASCII this is octal code 015.
2301 @c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
2302 @c other assemblers.
2304 @cindex @code{\t} (tab)
2305 @cindex tab (@code{\t})
2307 Mnemonic for horizontal Tab; for ASCII this is octal code 011.
2310 @c Mnemonic for Vertical tab; for ASCII this is octal code 013.
2311 @c @item \x @var{digit} @var{digit} @var{digit}
2312 @c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
2314 @cindex @code{\@var{ddd}} (octal character code)
2315 @cindex octal character code (@code{\@var{ddd}})
2316 @item \ @var{digit} @var{digit} @var{digit}
2317 An octal character code. The numeric code is 3 octal digits.
2318 For compatibility with other Unix systems, 8 and 9 are accepted as digits:
2319 for example, @code{\008} has the value 010, and @code{\009} the value 011.
2321 @cindex @code{\@var{xd...}} (hex character code)
2322 @cindex hex character code (@code{\@var{xd...}})
2323 @item \@code{x} @var{hex-digits...}
2324 A hex character code. All trailing hex digits are combined. Either upper or
2325 lower case @code{x} works.
2327 @cindex @code{\\} (@samp{\} character)
2328 @cindex backslash (@code{\\})
2330 Represents one @samp{\} character.
2333 @c Represents one @samp{'} (accent acute) character.
2334 @c This is needed in single character literals
2335 @c (@xref{Characters,,Character Constants}.) to represent
2338 @cindex @code{\"} (doublequote character)
2339 @cindex doublequote (@code{\"})
2341 Represents one @samp{"} character. Needed in strings to represent
2342 this character, because an unescaped @samp{"} would end the string.
2344 @item \ @var{anything-else}
2345 Any other character when escaped by @kbd{\} gives a warning, but
2346 assembles as if the @samp{\} was not present. The idea is that if
2347 you used an escape sequence you clearly didn't want the literal
2348 interpretation of the following character. However @command{@value{AS}} has no
2349 other interpretation, so @command{@value{AS}} knows it is giving you the wrong
2350 code and warns you of the fact.
2353 Which characters are escapable, and what those escapes represent,
2354 varies widely among assemblers. The current set is what we think
2355 the BSD 4.2 assembler recognizes, and is a subset of what most C
2356 compilers recognize. If you are in doubt, do not use an escape
2360 @subsubsection Characters
2362 @cindex single character constant
2363 @cindex character, single
2364 @cindex constant, single character
2365 A single character may be written as a single quote immediately
2366 followed by that character. The same escapes apply to characters as
2367 to strings. So if you want to write the character backslash, you
2368 must write @kbd{'\\} where the first @code{\} escapes the second
2369 @code{\}. As you can see, the quote is an acute accent, not a
2370 grave accent. A newline
2372 @ifclear abnormal-separator
2373 (or semicolon @samp{;})
2375 @ifset abnormal-separator
2377 (or at sign @samp{@@})
2380 (or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the
2386 immediately following an acute accent is taken as a literal character
2387 and does not count as the end of a statement. The value of a character
2388 constant in a numeric expression is the machine's byte-wide code for
2389 that character. @command{@value{AS}} assumes your character code is ASCII:
2390 @kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill
2393 @subsection Number Constants
2395 @cindex constants, number
2396 @cindex number constants
2397 @command{@value{AS}} distinguishes three kinds of numbers according to how they
2398 are stored in the target machine. @emph{Integers} are numbers that
2399 would fit into an @code{int} in the C language. @emph{Bignums} are
2400 integers, but they are stored in more than 32 bits. @emph{Flonums}
2401 are floating point numbers, described below.
2404 * Integers:: Integers
2409 * Bit Fields:: Bit Fields
2415 @subsubsection Integers
2417 @cindex constants, integer
2419 @cindex binary integers
2420 @cindex integers, binary
2421 A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
2422 the binary digits @samp{01}.
2424 @cindex octal integers
2425 @cindex integers, octal
2426 An octal integer is @samp{0} followed by zero or more of the octal
2427 digits (@samp{01234567}).
2429 @cindex decimal integers
2430 @cindex integers, decimal
2431 A decimal integer starts with a non-zero digit followed by zero or
2432 more digits (@samp{0123456789}).
2434 @cindex hexadecimal integers
2435 @cindex integers, hexadecimal
2436 A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
2437 more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
2439 Integers have the usual values. To denote a negative integer, use
2440 the prefix operator @samp{-} discussed under expressions
2441 (@pxref{Prefix Ops,,Prefix Operators}).
2444 @subsubsection Bignums
2447 @cindex constants, bignum
2448 A @dfn{bignum} has the same syntax and semantics as an integer
2449 except that the number (or its negative) takes more than 32 bits to
2450 represent in binary. The distinction is made because in some places
2451 integers are permitted while bignums are not.
2454 @subsubsection Flonums
2456 @cindex floating point numbers
2457 @cindex constants, floating point
2459 @cindex precision, floating point
2460 A @dfn{flonum} represents a floating point number. The translation is
2461 indirect: a decimal floating point number from the text is converted by
2462 @command{@value{AS}} to a generic binary floating point number of more than
2463 sufficient precision. This generic floating point number is converted
2464 to a particular computer's floating point format (or formats) by a
2465 portion of @command{@value{AS}} specialized to that computer.
2467 A flonum is written by writing (in order)
2472 (@samp{0} is optional on the HPPA.)
2476 A letter, to tell @command{@value{AS}} the rest of the number is a flonum.
2478 @kbd{e} is recommended. Case is not important.
2480 @c FIXME: verify if flonum syntax really this vague for most cases
2481 (Any otherwise illegal letter works here, but that might be changed. Vax BSD
2482 4.2 assembler seems to allow any of @samp{defghDEFGH}.)
2485 On the H8/300, H8/500,
2487 and AMD 29K architectures, the letter must be
2488 one of the letters @samp{DFPRSX} (in upper or lower case).
2490 On the ARC, the letter must be one of the letters @samp{DFRS}
2491 (in upper or lower case).
2493 On the Intel 960 architecture, the letter must be
2494 one of the letters @samp{DFT} (in upper or lower case).
2496 On the HPPA architecture, the letter must be @samp{E} (upper case only).
2500 One of the letters @samp{DFPRSX} (in upper or lower case).
2503 One of the letters @samp{DFRS} (in upper or lower case).
2506 One of the letters @samp{DFPRSX} (in upper or lower case).
2509 The letter @samp{E} (upper case only).
2512 One of the letters @samp{DFT} (in upper or lower case).
2517 An optional sign: either @samp{+} or @samp{-}.
2520 An optional @dfn{integer part}: zero or more decimal digits.
2523 An optional @dfn{fractional part}: @samp{.} followed by zero
2524 or more decimal digits.
2527 An optional exponent, consisting of:
2531 An @samp{E} or @samp{e}.
2532 @c I can't find a config where "EXP_CHARS" is other than 'eE', but in
2533 @c principle this can perfectly well be different on different targets.
2535 Optional sign: either @samp{+} or @samp{-}.
2537 One or more decimal digits.
2542 At least one of the integer part or the fractional part must be
2543 present. The floating point number has the usual base-10 value.
2545 @command{@value{AS}} does all processing using integers. Flonums are computed
2546 independently of any floating point hardware in the computer running
2547 @command{@value{AS}}.
2551 @c Bit fields are written as a general facility but are also controlled
2552 @c by a conditional-compilation flag---which is as of now (21mar91)
2553 @c turned on only by the i960 config of GAS.
2555 @subsubsection Bit Fields
2558 @cindex constants, bit field
2559 You can also define numeric constants as @dfn{bit fields}.
2560 specify two numbers separated by a colon---
2562 @var{mask}:@var{value}
2565 @command{@value{AS}} applies a bitwise @sc{and} between @var{mask} and
2568 The resulting number is then packed
2570 @c this conditional paren in case bit fields turned on elsewhere than 960
2571 (in host-dependent byte order)
2573 into a field whose width depends on which assembler directive has the
2574 bit-field as its argument. Overflow (a result from the bitwise and
2575 requiring more binary digits to represent) is not an error; instead,
2576 more constants are generated, of the specified width, beginning with the
2577 least significant digits.@refill
2579 The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long},
2580 @code{.short}, and @code{.word} accept bit-field arguments.
2585 @chapter Sections and Relocation
2590 * Secs Background:: Background
2591 * Ld Sections:: Linker Sections
2592 * As Sections:: Assembler Internal Sections
2593 * Sub-Sections:: Sub-Sections
2597 @node Secs Background
2600 Roughly, a section is a range of addresses, with no gaps; all data
2601 ``in'' those addresses is treated the same for some particular purpose.
2602 For example there may be a ``read only'' section.
2604 @cindex linker, and assembler
2605 @cindex assembler, and linker
2606 The linker @code{@value{LD}} reads many object files (partial programs) and
2607 combines their contents to form a runnable program. When @command{@value{AS}}
2608 emits an object file, the partial program is assumed to start at address 0.
2609 @code{@value{LD}} assigns the final addresses for the partial program, so that
2610 different partial programs do not overlap. This is actually an
2611 oversimplification, but it suffices to explain how @command{@value{AS}} uses
2614 @code{@value{LD}} moves blocks of bytes of your program to their run-time
2615 addresses. These blocks slide to their run-time addresses as rigid
2616 units; their length does not change and neither does the order of bytes
2617 within them. Such a rigid unit is called a @emph{section}. Assigning
2618 run-time addresses to sections is called @dfn{relocation}. It includes
2619 the task of adjusting mentions of object-file addresses so they refer to
2620 the proper run-time addresses.
2622 For the H8/300 and H8/500,
2623 and for the Hitachi SH,
2624 @command{@value{AS}} pads sections if needed to
2625 ensure they end on a word (sixteen bit) boundary.
2628 @cindex standard assembler sections
2629 An object file written by @command{@value{AS}} has at least three sections, any
2630 of which may be empty. These are named @dfn{text}, @dfn{data} and
2635 When it generates COFF output,
2637 @command{@value{AS}} can also generate whatever other named sections you specify
2638 using the @samp{.section} directive (@pxref{Section,,@code{.section}}).
2639 If you do not use any directives that place output in the @samp{.text}
2640 or @samp{.data} sections, these sections still exist, but are empty.
2645 When @command{@value{AS}} generates SOM or ELF output for the HPPA,
2647 @command{@value{AS}} can also generate whatever other named sections you
2648 specify using the @samp{.space} and @samp{.subspace} directives. See
2649 @cite{HP9000 Series 800 Assembly Language Reference Manual}
2650 (HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
2651 assembler directives.
2654 Additionally, @command{@value{AS}} uses different names for the standard
2655 text, data, and bss sections when generating SOM output. Program text
2656 is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
2657 BSS into @samp{$BSS$}.
2661 Within the object file, the text section starts at address @code{0}, the
2662 data section follows, and the bss section follows the data section.
2665 When generating either SOM or ELF output files on the HPPA, the text
2666 section starts at address @code{0}, the data section at address
2667 @code{0x4000000}, and the bss section follows the data section.
2670 To let @code{@value{LD}} know which data changes when the sections are
2671 relocated, and how to change that data, @command{@value{AS}} also writes to the
2672 object file details of the relocation needed. To perform relocation
2673 @code{@value{LD}} must know, each time an address in the object
2677 Where in the object file is the beginning of this reference to
2680 How long (in bytes) is this reference?
2682 Which section does the address refer to? What is the numeric value of
2684 (@var{address}) @minus{} (@var{start-address of section})?
2687 Is the reference to an address ``Program-Counter relative''?
2690 @cindex addresses, format of
2691 @cindex section-relative addressing
2692 In fact, every address @command{@value{AS}} ever uses is expressed as
2694 (@var{section}) + (@var{offset into section})
2697 Further, most expressions @command{@value{AS}} computes have this section-relative
2700 (For some object formats, such as SOM for the HPPA, some expressions are
2701 symbol-relative instead.)
2704 In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset
2705 @var{N} into section @var{secname}.''
2707 Apart from text, data and bss sections you need to know about the
2708 @dfn{absolute} section. When @code{@value{LD}} mixes partial programs,
2709 addresses in the absolute section remain unchanged. For example, address
2710 @code{@{absolute 0@}} is ``relocated'' to run-time address 0 by
2711 @code{@value{LD}}. Although the linker never arranges two partial programs'
2712 data sections with overlapping addresses after linking, @emph{by definition}
2713 their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one
2714 part of a program is always the same address when the program is running as
2715 address @code{@{absolute@ 239@}} in any other part of the program.
2717 The idea of sections is extended to the @dfn{undefined} section. Any
2718 address whose section is unknown at assembly time is by definition
2719 rendered @{undefined @var{U}@}---where @var{U} is filled in later.
2720 Since numbers are always defined, the only way to generate an undefined
2721 address is to mention an undefined symbol. A reference to a named
2722 common block would be such a symbol: its value is unknown at assembly
2723 time so it has section @emph{undefined}.
2725 By analogy the word @emph{section} is used to describe groups of sections in
2726 the linked program. @code{@value{LD}} puts all partial programs' text
2727 sections in contiguous addresses in the linked program. It is
2728 customary to refer to the @emph{text section} of a program, meaning all
2729 the addresses of all partial programs' text sections. Likewise for
2730 data and bss sections.
2732 Some sections are manipulated by @code{@value{LD}}; others are invented for
2733 use of @command{@value{AS}} and have no meaning except during assembly.
2736 @section Linker Sections
2737 @code{@value{LD}} deals with just four kinds of sections, summarized below.
2742 @cindex named sections
2743 @cindex sections, named
2744 @item named sections
2747 @cindex text section
2748 @cindex data section
2752 These sections hold your program. @command{@value{AS}} and @code{@value{LD}} treat them as
2753 separate but equal sections. Anything you can say of one section is
2756 When the program is running, however, it is
2757 customary for the text section to be unalterable. The
2758 text section is often shared among processes: it contains
2759 instructions, constants and the like. The data section of a running
2760 program is usually alterable: for example, C variables would be stored
2761 in the data section.
2766 This section contains zeroed bytes when your program begins running. It
2767 is used to hold uninitialized variables or common storage. The length of
2768 each partial program's bss section is important, but because it starts
2769 out containing zeroed bytes there is no need to store explicit zero
2770 bytes in the object file. The bss section was invented to eliminate
2771 those explicit zeros from object files.
2773 @cindex absolute section
2774 @item absolute section
2775 Address 0 of this section is always ``relocated'' to runtime address 0.
2776 This is useful if you want to refer to an address that @code{@value{LD}} must
2777 not change when relocating. In this sense we speak of absolute
2778 addresses being ``unrelocatable'': they do not change during relocation.
2780 @cindex undefined section
2781 @item undefined section
2782 This ``section'' is a catch-all for address references to objects not in
2783 the preceding sections.
2784 @c FIXME: ref to some other doc on obj-file formats could go here.
2787 @cindex relocation example
2788 An idealized example of three relocatable sections follows.
2790 The example uses the traditional section names @samp{.text} and @samp{.data}.
2792 Memory addresses are on the horizontal axis.
2796 @c END TEXI2ROFF-KILL
2799 partial program # 1: |ttttt|dddd|00|
2806 partial program # 2: |TTT|DDD|000|
2809 +--+---+-----+--+----+---+-----+~~
2810 linked program: | |TTT|ttttt| |dddd|DDD|00000|
2811 +--+---+-----+--+----+---+-----+~~
2813 addresses: 0 @dots{}
2820 \line{\it Partial program \#1: \hfil}
2821 \line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2822 \line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
2824 \line{\it Partial program \#2: \hfil}
2825 \line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2826 \line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
2828 \line{\it linked program: \hfil}
2829 \line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
2830 \line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
2831 ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
2832 DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
2834 \line{\it addresses: \hfil}
2838 @c END TEXI2ROFF-KILL
2841 @section Assembler Internal Sections
2843 @cindex internal assembler sections
2844 @cindex sections in messages, internal
2845 These sections are meant only for the internal use of @command{@value{AS}}. They
2846 have no meaning at run-time. You do not really need to know about these
2847 sections for most purposes; but they can be mentioned in @command{@value{AS}}
2848 warning messages, so it might be helpful to have an idea of their
2849 meanings to @command{@value{AS}}. These sections are used to permit the
2850 value of every expression in your assembly language program to be a
2851 section-relative address.
2854 @cindex assembler internal logic error
2855 @item ASSEMBLER-INTERNAL-LOGIC-ERROR!
2856 An internal assembler logic error has been found. This means there is a
2857 bug in the assembler.
2859 @cindex expr (internal section)
2861 The assembler stores complex expression internally as combinations of
2862 symbols. When it needs to represent an expression as a symbol, it puts
2863 it in the expr section.
2865 @c FIXME item transfer[t] vector preload
2866 @c FIXME item transfer[t] vector postload
2867 @c FIXME item register
2871 @section Sub-Sections
2873 @cindex numbered subsections
2874 @cindex grouping data
2880 fall into two sections: text and data.
2882 You may have separate groups of
2884 data in named sections
2888 data in named sections
2894 that you want to end up near to each other in the object file, even though they
2895 are not contiguous in the assembler source. @command{@value{AS}} allows you to
2896 use @dfn{subsections} for this purpose. Within each section, there can be
2897 numbered subsections with values from 0 to 8192. Objects assembled into the
2898 same subsection go into the object file together with other objects in the same
2899 subsection. For example, a compiler might want to store constants in the text
2900 section, but might not want to have them interspersed with the program being
2901 assembled. In this case, the compiler could issue a @samp{.text 0} before each
2902 section of code being output, and a @samp{.text 1} before each group of
2903 constants being output.
2905 Subsections are optional. If you do not use subsections, everything
2906 goes in subsection number zero.
2909 Each subsection is zero-padded up to a multiple of four bytes.
2910 (Subsections may be padded a different amount on different flavors
2911 of @command{@value{AS}}.)
2915 On the H8/300 and H8/500 platforms, each subsection is zero-padded to a word
2916 boundary (two bytes).
2917 The same is true on the Hitachi SH.
2920 @c FIXME section padding (alignment)?
2921 @c Rich Pixley says padding here depends on target obj code format; that
2922 @c doesn't seem particularly useful to say without further elaboration,
2923 @c so for now I say nothing about it. If this is a generic BFD issue,
2924 @c these paragraphs might need to vanish from this manual, and be
2925 @c discussed in BFD chapter of binutils (or some such).
2928 On the AMD 29K family, no particular padding is added to section or
2929 subsection sizes; @value{AS} forces no alignment on this platform.
2933 Subsections appear in your object file in numeric order, lowest numbered
2934 to highest. (All this to be compatible with other people's assemblers.)
2935 The object file contains no representation of subsections; @code{@value{LD}} and
2936 other programs that manipulate object files see no trace of them.
2937 They just see all your text subsections as a text section, and all your
2938 data subsections as a data section.
2940 To specify which subsection you want subsequent statements assembled
2941 into, use a numeric argument to specify it, in a @samp{.text
2942 @var{expression}} or a @samp{.data @var{expression}} statement.
2945 When generating COFF output, you
2950 can also use an extra subsection
2951 argument with arbitrary named sections: @samp{.section @var{name},
2954 @var{Expression} should be an absolute expression.
2955 (@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0}
2956 is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
2957 begins in @code{text 0}. For instance:
2959 .text 0 # The default subsection is text 0 anyway.
2960 .ascii "This lives in the first text subsection. *"
2962 .ascii "But this lives in the second text subsection."
2964 .ascii "This lives in the data section,"
2965 .ascii "in the first data subsection."
2967 .ascii "This lives in the first text section,"
2968 .ascii "immediately following the asterisk (*)."
2971 Each section has a @dfn{location counter} incremented by one for every byte
2972 assembled into that section. Because subsections are merely a convenience
2973 restricted to @command{@value{AS}} there is no concept of a subsection location
2974 counter. There is no way to directly manipulate a location counter---but the
2975 @code{.align} directive changes it, and any label definition captures its
2976 current value. The location counter of the section where statements are being
2977 assembled is said to be the @dfn{active} location counter.
2980 @section bss Section
2983 @cindex common variable storage
2984 The bss section is used for local common variable storage.
2985 You may allocate address space in the bss section, but you may
2986 not dictate data to load into it before your program executes. When
2987 your program starts running, all the contents of the bss
2988 section are zeroed bytes.
2990 The @code{.lcomm} pseudo-op defines a symbol in the bss section; see
2991 @ref{Lcomm,,@code{.lcomm}}.
2993 The @code{.comm} pseudo-op may be used to declare a common symbol, which is
2994 another form of uninitialized symbol; see @xref{Comm,,@code{.comm}}.
2997 When assembling for a target which supports multiple sections, such as ELF or
2998 COFF, you may switch into the @code{.bss} section and define symbols as usual;
2999 see @ref{Section,,@code{.section}}. You may only assemble zero values into the
3000 section. Typically the section will only contain symbol definitions and
3001 @code{.skip} directives (@pxref{Skip,,@code{.skip}}).
3008 Symbols are a central concept: the programmer uses symbols to name
3009 things, the linker uses symbols to link, and the debugger uses symbols
3013 @cindex debuggers, and symbol order
3014 @emph{Warning:} @command{@value{AS}} does not place symbols in the object file in
3015 the same order they were declared. This may break some debuggers.
3020 * Setting Symbols:: Giving Symbols Other Values
3021 * Symbol Names:: Symbol Names
3022 * Dot:: The Special Dot Symbol
3023 * Symbol Attributes:: Symbol Attributes
3030 A @dfn{label} is written as a symbol immediately followed by a colon
3031 @samp{:}. The symbol then represents the current value of the
3032 active location counter, and is, for example, a suitable instruction
3033 operand. You are warned if you use the same symbol to represent two
3034 different locations: the first definition overrides any other
3038 On the HPPA, the usual form for a label need not be immediately followed by a
3039 colon, but instead must start in column zero. Only one label may be defined on
3040 a single line. To work around this, the HPPA version of @command{@value{AS}} also
3041 provides a special directive @code{.label} for defining labels more flexibly.
3044 @node Setting Symbols
3045 @section Giving Symbols Other Values
3047 @cindex assigning values to symbols
3048 @cindex symbol values, assigning
3049 A symbol can be given an arbitrary value by writing a symbol, followed
3050 by an equals sign @samp{=}, followed by an expression
3051 (@pxref{Expressions}). This is equivalent to using the @code{.set}
3052 directive. @xref{Set,,@code{.set}}.
3055 @section Symbol Names
3057 @cindex symbol names
3058 @cindex names, symbol
3059 @ifclear SPECIAL-SYMS
3060 Symbol names begin with a letter or with one of @samp{._}. On most
3061 machines, you can also use @code{$} in symbol names; exceptions are
3062 noted in @ref{Machine Dependencies}. That character may be followed by any
3063 string of digits, letters, dollar signs (unless otherwise noted in
3064 @ref{Machine Dependencies}), and underscores.
3067 For the AMD 29K family, @samp{?} is also allowed in the
3068 body of a symbol name, though not at its beginning.
3073 Symbol names begin with a letter or with one of @samp{._}. On the
3075 H8/500, you can also use @code{$} in symbol names. That character may
3076 be followed by any string of digits, letters, dollar signs (save on the
3077 H8/300), and underscores.
3081 Case of letters is significant: @code{foo} is a different symbol name
3084 Each symbol has exactly one name. Each name in an assembly language program
3085 refers to exactly one symbol. You may use that symbol name any number of times
3088 @subheading Local Symbol Names
3090 @cindex local symbol names
3091 @cindex symbol names, local
3092 @cindex temporary symbol names
3093 @cindex symbol names, temporary
3094 Local symbols help compilers and programmers use names temporarily.
3095 They create symbols which are guaranteed to be unique over the entire scope of
3096 the input source code and which can be referred to by a simple notation.
3097 To define a local symbol, write a label of the form @samp{@b{N}:} (where @b{N}
3098 represents any positive integer). To refer to the most recent previous
3099 definition of that symbol write @samp{@b{N}b}, using the same number as when
3100 you defined the label. To refer to the next definition of a local label, write
3101 @samp{@b{N}f}--- The @samp{b} stands for``backwards'' and the @samp{f} stands
3104 There is no restriction on how you can use these labels, and you can reuse them
3105 too. So that it is possible to repeatedly define the same local label (using
3106 the same number @samp{@b{N}}), although you can only refer to the most recently
3107 defined local label of that number (for a backwards reference) or the next
3108 definition of a specific local label for a forward reference. It is also worth
3109 noting that the first 10 local labels (@samp{@b{0:}}@dots{}@samp{@b{9:}}) are
3110 implemented in a slightly more efficient manner than the others.
3121 Which is the equivalent of:
3124 label_1: branch label_3
3125 label_2: branch label_1
3126 label_3: branch label_4
3127 label_4: branch label_3
3130 Local symbol names are only a notational device. They are immediately
3131 transformed into more conventional symbol names before the assembler uses them.
3132 The symbol names stored in the symbol table, appearing in error messages and
3133 optionally emitted to the object file. The names are constructed using these
3138 All local labels begin with @samp{L}. Normally both @command{@value{AS}} and
3139 @code{@value{LD}} forget symbols that start with @samp{L}. These labels are
3140 used for symbols you are never intended to see. If you use the
3141 @samp{-L} option then @command{@value{AS}} retains these symbols in the
3142 object file. If you also instruct @code{@value{LD}} to retain these symbols,
3143 you may use them in debugging.
3146 This is the number that was used in the local label definition. So if the
3147 label is written @samp{55:} then the number is @samp{55}.
3150 This unusual character is included so you do not accidentally invent a symbol
3151 of the same name. The character has ASCII value of @samp{\002} (control-B).
3153 @item @emph{ordinal number}
3154 This is a serial number to keep the labels distinct. The first definition of
3155 @samp{0:} gets the number @samp{1}. The 15th definition of @samp{0:} gets the
3156 number @samp{15}, and so on. Likewise the first definition of @samp{1:} gets
3157 the number @samp{1} and its 15th defintion gets @samp{15} as well.
3160 So for example, the first @code{1:} is named @code{L1@kbd{C-B}1}, the 44th
3161 @code{3:} is named @code{L3@kbd{C-B}44}.
3163 @subheading Dollar Local Labels
3164 @cindex dollar local symbols
3166 @code{@value{AS}} also supports an even more local form of local labels called
3167 dollar labels. These labels go out of scope (ie they become undefined) as soon
3168 as a non-local label is defined. Thus they remain valid for only a small
3169 region of the input source code. Normal local labels, by contrast, remain in
3170 scope for the entire file, or until they are redefined by another occurrence of
3171 the same local label.
3173 Dollar labels are defined in exactly the same way as ordinary local labels,
3174 except that instead of being terminated by a colon, they are terminated by a
3175 dollar sign. eg @samp{@b{55$}}.
3177 They can also be distinguished from ordinary local labels by their transformed
3178 name which uses ASCII character @samp{\001} (control-A) as the magic character
3179 to distinguish them from ordinary labels. Thus the 5th defintion of @samp{6$}
3180 is named @samp{L6@kbd{C-A}5}.
3183 @section The Special Dot Symbol
3185 @cindex dot (symbol)
3186 @cindex @code{.} (symbol)
3187 @cindex current address
3188 @cindex location counter
3189 The special symbol @samp{.} refers to the current address that
3190 @command{@value{AS}} is assembling into. Thus, the expression @samp{melvin:
3191 .long .} defines @code{melvin} to contain its own address.
3192 Assigning a value to @code{.} is treated the same as a @code{.org}
3193 directive. Thus, the expression @samp{.=.+4} is the same as saying
3194 @ifclear no-space-dir
3203 @node Symbol Attributes
3204 @section Symbol Attributes
3206 @cindex symbol attributes
3207 @cindex attributes, symbol
3208 Every symbol has, as well as its name, the attributes ``Value'' and
3209 ``Type''. Depending on output format, symbols can also have auxiliary
3212 The detailed definitions are in @file{a.out.h}.
3215 If you use a symbol without defining it, @command{@value{AS}} assumes zero for
3216 all these attributes, and probably won't warn you. This makes the
3217 symbol an externally defined symbol, which is generally what you
3221 * Symbol Value:: Value
3222 * Symbol Type:: Type
3225 * a.out Symbols:: Symbol Attributes: @code{a.out}
3229 * a.out Symbols:: Symbol Attributes: @code{a.out}
3232 * a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out}
3237 * COFF Symbols:: Symbol Attributes for COFF
3240 * SOM Symbols:: Symbol Attributes for SOM
3247 @cindex value of a symbol
3248 @cindex symbol value
3249 The value of a symbol is (usually) 32 bits. For a symbol which labels a
3250 location in the text, data, bss or absolute sections the value is the
3251 number of addresses from the start of that section to the label.
3252 Naturally for text, data and bss sections the value of a symbol changes
3253 as @code{@value{LD}} changes section base addresses during linking. Absolute
3254 symbols' values do not change during linking: that is why they are
3257 The value of an undefined symbol is treated in a special way. If it is
3258 0 then the symbol is not defined in this assembler source file, and
3259 @code{@value{LD}} tries to determine its value from other files linked into the
3260 same program. You make this kind of symbol simply by mentioning a symbol
3261 name without defining it. A non-zero value represents a @code{.comm}
3262 common declaration. The value is how much common storage to reserve, in
3263 bytes (addresses). The symbol refers to the first address of the
3269 @cindex type of a symbol
3271 The type attribute of a symbol contains relocation (section)
3272 information, any flag settings indicating that a symbol is external, and
3273 (optionally), other information for linkers and debuggers. The exact
3274 format depends on the object-code output format in use.
3279 @c The following avoids a "widow" subsection title. @group would be
3280 @c better if it were available outside examples.
3283 @subsection Symbol Attributes: @code{a.out}, @code{b.out}
3285 @cindex @code{b.out} symbol attributes
3286 @cindex symbol attributes, @code{b.out}
3287 These symbol attributes appear only when @command{@value{AS}} is configured for
3288 one of the Berkeley-descended object output formats---@code{a.out} or
3294 @subsection Symbol Attributes: @code{a.out}
3296 @cindex @code{a.out} symbol attributes
3297 @cindex symbol attributes, @code{a.out}
3303 @subsection Symbol Attributes: @code{a.out}
3305 @cindex @code{a.out} symbol attributes
3306 @cindex symbol attributes, @code{a.out}
3310 * Symbol Desc:: Descriptor
3311 * Symbol Other:: Other
3315 @subsubsection Descriptor
3317 @cindex descriptor, of @code{a.out} symbol
3318 This is an arbitrary 16-bit value. You may establish a symbol's
3319 descriptor value by using a @code{.desc} statement
3320 (@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
3321 @command{@value{AS}}.
3324 @subsubsection Other
3326 @cindex other attribute, of @code{a.out} symbol
3327 This is an arbitrary 8-bit value. It means nothing to @command{@value{AS}}.
3332 @subsection Symbol Attributes for COFF
3334 @cindex COFF symbol attributes
3335 @cindex symbol attributes, COFF
3337 The COFF format supports a multitude of auxiliary symbol attributes;
3338 like the primary symbol attributes, they are set between @code{.def} and
3339 @code{.endef} directives.
3341 @subsubsection Primary Attributes
3343 @cindex primary attributes, COFF symbols
3344 The symbol name is set with @code{.def}; the value and type,
3345 respectively, with @code{.val} and @code{.type}.
3347 @subsubsection Auxiliary Attributes
3349 @cindex auxiliary attributes, COFF symbols
3350 The @command{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
3351 @code{.size}, and @code{.tag} can generate auxiliary symbol table
3352 information for COFF.
3357 @subsection Symbol Attributes for SOM
3359 @cindex SOM symbol attributes
3360 @cindex symbol attributes, SOM
3362 The SOM format for the HPPA supports a multitude of symbol attributes set with
3363 the @code{.EXPORT} and @code{.IMPORT} directives.
3365 The attributes are described in @cite{HP9000 Series 800 Assembly
3366 Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
3367 @code{EXPORT} assembler directive documentation.
3371 @chapter Expressions
3375 @cindex numeric values
3376 An @dfn{expression} specifies an address or numeric value.
3377 Whitespace may precede and/or follow an expression.
3379 The result of an expression must be an absolute number, or else an offset into
3380 a particular section. If an expression is not absolute, and there is not
3381 enough information when @command{@value{AS}} sees the expression to know its
3382 section, a second pass over the source program might be necessary to interpret
3383 the expression---but the second pass is currently not implemented.
3384 @command{@value{AS}} aborts with an error message in this situation.
3387 * Empty Exprs:: Empty Expressions
3388 * Integer Exprs:: Integer Expressions
3392 @section Empty Expressions
3394 @cindex empty expressions
3395 @cindex expressions, empty
3396 An empty expression has no value: it is just whitespace or null.
3397 Wherever an absolute expression is required, you may omit the
3398 expression, and @command{@value{AS}} assumes a value of (absolute) 0. This
3399 is compatible with other assemblers.
3402 @section Integer Expressions
3404 @cindex integer expressions
3405 @cindex expressions, integer
3406 An @dfn{integer expression} is one or more @emph{arguments} delimited
3407 by @emph{operators}.
3410 * Arguments:: Arguments
3411 * Operators:: Operators
3412 * Prefix Ops:: Prefix Operators
3413 * Infix Ops:: Infix Operators
3417 @subsection Arguments
3419 @cindex expression arguments
3420 @cindex arguments in expressions
3421 @cindex operands in expressions
3422 @cindex arithmetic operands
3423 @dfn{Arguments} are symbols, numbers or subexpressions. In other
3424 contexts arguments are sometimes called ``arithmetic operands''. In
3425 this manual, to avoid confusing them with the ``instruction operands'' of
3426 the machine language, we use the term ``argument'' to refer to parts of
3427 expressions only, reserving the word ``operand'' to refer only to machine
3428 instruction operands.
3430 Symbols are evaluated to yield @{@var{section} @var{NNN}@} where
3431 @var{section} is one of text, data, bss, absolute,
3432 or undefined. @var{NNN} is a signed, 2's complement 32 bit
3435 Numbers are usually integers.
3437 A number can be a flonum or bignum. In this case, you are warned
3438 that only the low order 32 bits are used, and @command{@value{AS}} pretends
3439 these 32 bits are an integer. You may write integer-manipulating
3440 instructions that act on exotic constants, compatible with other
3443 @cindex subexpressions
3444 Subexpressions are a left parenthesis @samp{(} followed by an integer
3445 expression, followed by a right parenthesis @samp{)}; or a prefix
3446 operator followed by an argument.
3449 @subsection Operators
3451 @cindex operators, in expressions
3452 @cindex arithmetic functions
3453 @cindex functions, in expressions
3454 @dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
3455 operators are followed by an argument. Infix operators appear
3456 between their arguments. Operators may be preceded and/or followed by
3460 @subsection Prefix Operator
3462 @cindex prefix operators
3463 @command{@value{AS}} has the following @dfn{prefix operators}. They each take
3464 one argument, which must be absolute.
3466 @c the tex/end tex stuff surrounding this small table is meant to make
3467 @c it align, on the printed page, with the similar table in the next
3468 @c section (which is inside an enumerate).
3470 \global\advance\leftskip by \itemindent
3475 @dfn{Negation}. Two's complement negation.
3477 @dfn{Complementation}. Bitwise not.
3481 \global\advance\leftskip by -\itemindent
3485 @subsection Infix Operators
3487 @cindex infix operators
3488 @cindex operators, permitted arguments
3489 @dfn{Infix operators} take two arguments, one on either side. Operators
3490 have precedence, but operations with equal precedence are performed left
3491 to right. Apart from @code{+} or @option{-}, both arguments must be
3492 absolute, and the result is absolute.
3495 @cindex operator precedence
3496 @cindex precedence of operators
3503 @dfn{Multiplication}.
3506 @dfn{Division}. Truncation is the same as the C operator @samp{/}
3513 @dfn{Shift Left}. Same as the C operator @samp{<<}.
3517 @dfn{Shift Right}. Same as the C operator @samp{>>}.
3521 Intermediate precedence
3526 @dfn{Bitwise Inclusive Or}.
3532 @dfn{Bitwise Exclusive Or}.
3535 @dfn{Bitwise Or Not}.
3542 @cindex addition, permitted arguments
3543 @cindex plus, permitted arguments
3544 @cindex arguments for addition
3546 @dfn{Addition}. If either argument is absolute, the result has the section of
3547 the other argument. You may not add together arguments from different
3550 @cindex subtraction, permitted arguments
3551 @cindex minus, permitted arguments
3552 @cindex arguments for subtraction
3554 @dfn{Subtraction}. If the right argument is absolute, the
3555 result has the section of the left argument.
3556 If both arguments are in the same section, the result is absolute.
3557 You may not subtract arguments from different sections.
3558 @c FIXME is there still something useful to say about undefined - undefined ?
3560 @cindex comparison expressions
3561 @cindex expressions, comparison
3565 @dfn{Is Not Equal To}
3569 @dfn{Is Greater Than}
3571 @dfn{Is Greater Than Or Equal To}
3573 @dfn{Is Less Than Or Equal To}
3575 The comparison operators can be used as infix operators. A true results has a
3576 value of -1 whereas a false result has a value of 0. Note, these operators
3577 perform signed comparisons.
3580 @item Lowest Precedence
3589 These two logical operations can be used to combine the results of sub
3590 expressions. Note, unlike the comparison operators a true result returns a
3591 value of 1 but a false results does still return 0. Also note that the logical
3592 or operator has a slightly lower precedence than logical and.
3597 In short, it's only meaningful to add or subtract the @emph{offsets} in an
3598 address; you can only have a defined section in one of the two arguments.
3601 @chapter Assembler Directives
3603 @cindex directives, machine independent
3604 @cindex pseudo-ops, machine independent
3605 @cindex machine independent directives
3606 All assembler directives have names that begin with a period (@samp{.}).
3607 The rest of the name is letters, usually in lower case.
3609 This chapter discusses directives that are available regardless of the
3610 target machine configuration for the @sc{gnu} assembler.
3612 Some machine configurations provide additional directives.
3613 @xref{Machine Dependencies}.
3616 @ifset machine-directives
3617 @xref{Machine Dependencies} for additional directives.
3622 * Abort:: @code{.abort}
3624 * ABORT:: @code{.ABORT}
3627 * Align:: @code{.align @var{abs-expr} , @var{abs-expr}}
3628 * Ascii:: @code{.ascii "@var{string}"}@dots{}
3629 * Asciz:: @code{.asciz "@var{string}"}@dots{}
3630 * Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}}
3631 * Byte:: @code{.byte @var{expressions}}
3632 * Comm:: @code{.comm @var{symbol} , @var{length} }
3633 * Data:: @code{.data @var{subsection}}
3635 * Def:: @code{.def @var{name}}
3638 * Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
3644 * Double:: @code{.double @var{flonums}}
3645 * Eject:: @code{.eject}
3646 * Else:: @code{.else}
3647 * Elseif:: @code{.elseif}
3650 * Endef:: @code{.endef}
3653 * Endfunc:: @code{.endfunc}
3654 * Endif:: @code{.endif}
3655 * Equ:: @code{.equ @var{symbol}, @var{expression}}
3656 * Equiv:: @code{.equiv @var{symbol}, @var{expression}}
3658 * Exitm:: @code{.exitm}
3659 * Extern:: @code{.extern}
3660 * Fail:: @code{.fail}
3661 @ifclear no-file-dir
3662 * File:: @code{.file @var{string}}
3665 * Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}}
3666 * Float:: @code{.float @var{flonums}}
3667 * Func:: @code{.func}
3668 * Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}}
3670 * Hidden:: @code{.hidden @var{names}}
3673 * hword:: @code{.hword @var{expressions}}
3674 * Ident:: @code{.ident}
3675 * If:: @code{.if @var{absolute expression}}
3676 * Incbin:: @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
3677 * Include:: @code{.include "@var{file}"}
3678 * Int:: @code{.int @var{expressions}}
3680 * Internal:: @code{.internal @var{names}}
3683 * Irp:: @code{.irp @var{symbol},@var{values}}@dots{}
3684 * Irpc:: @code{.irpc @var{symbol},@var{values}}@dots{}
3685 * Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
3686 * Lflags:: @code{.lflags}
3687 @ifclear no-line-dir
3688 * Line:: @code{.line @var{line-number}}
3691 * Ln:: @code{.ln @var{line-number}}
3692 * Linkonce:: @code{.linkonce [@var{type}]}
3693 * List:: @code{.list}
3694 * Long:: @code{.long @var{expressions}}
3696 * Lsym:: @code{.lsym @var{symbol}, @var{expression}}
3699 * Macro:: @code{.macro @var{name} @var{args}}@dots{}
3700 * MRI:: @code{.mri @var{val}}
3701 * Nolist:: @code{.nolist}
3702 * Octa:: @code{.octa @var{bignums}}
3703 * Org:: @code{.org @var{new-lc} , @var{fill}}
3704 * P2align:: @code{.p2align @var{abs-expr} , @var{abs-expr}}
3706 * PopSection:: @code{.popsection}
3707 * Previous:: @code{.previous}
3710 * Print:: @code{.print @var{string}}
3712 * Protected:: @code{.protected @var{names}}
3715 * Psize:: @code{.psize @var{lines}, @var{columns}}
3716 * Purgem:: @code{.purgem @var{name}}
3718 * PushSection:: @code{.pushsection @var{name}}
3721 * Quad:: @code{.quad @var{bignums}}
3722 * Rept:: @code{.rept @var{count}}
3723 * Sbttl:: @code{.sbttl "@var{subheading}"}
3725 * Scl:: @code{.scl @var{class}}
3726 * Section:: @code{.section @var{name}, @var{subsection}}
3729 * Set:: @code{.set @var{symbol}, @var{expression}}
3730 * Short:: @code{.short @var{expressions}}
3731 * Single:: @code{.single @var{flonums}}
3732 * Size:: @code{.size [@var{name} , @var{expression}]}
3733 * Skip:: @code{.skip @var{size} , @var{fill}}
3734 * Sleb128:: @code{.sleb128 @var{expressions}}
3735 * Space:: @code{.space @var{size} , @var{fill}}
3737 * Stab:: @code{.stabd, .stabn, .stabs}
3740 * String:: @code{.string "@var{str}"}
3741 * Struct:: @code{.struct @var{expression}}
3743 * SubSection:: @code{.subsection}
3744 * Symver:: @code{.symver @var{name},@var{name2@@nodename}}
3748 * Tag:: @code{.tag @var{structname}}
3751 * Text:: @code{.text @var{subsection}}
3752 * Title:: @code{.title "@var{heading}"}
3753 * Type:: @code{.type <@var{int} | @var{name} , @var{type description}>}
3754 * Uleb128:: @code{.uleb128 @var{expressions}}
3756 * Val:: @code{.val @var{addr}}
3760 * Version:: @code{.version "@var{string}"}
3761 * VTableEntry:: @code{.vtable_entry @var{table}, @var{offset}}
3762 * VTableInherit:: @code{.vtable_inherit @var{child}, @var{parent}}
3763 * Weak:: @code{.weak @var{names}}
3766 * Word:: @code{.word @var{expressions}}
3767 * Deprecated:: Deprecated Directives
3771 @section @code{.abort}
3773 @cindex @code{abort} directive
3774 @cindex stopping the assembly
3775 This directive stops the assembly immediately. It is for
3776 compatibility with other assemblers. The original idea was that the
3777 assembly language source would be piped into the assembler. If the sender
3778 of the source quit, it could use this directive tells @command{@value{AS}} to
3779 quit also. One day @code{.abort} will not be supported.
3783 @section @code{.ABORT}
3785 @cindex @code{ABORT} directive
3786 When producing COFF output, @command{@value{AS}} accepts this directive as a
3787 synonym for @samp{.abort}.
3790 When producing @code{b.out} output, @command{@value{AS}} accepts this directive,
3796 @section @code{.align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3798 @cindex padding the location counter
3799 @cindex @code{align} directive
3800 Pad the location counter (in the current subsection) to a particular storage
3801 boundary. The first expression (which must be absolute) is the alignment
3802 required, as described below.
3804 The second expression (also absolute) gives the fill value to be stored in the
3805 padding bytes. It (and the comma) may be omitted. If it is omitted, the
3806 padding bytes are normally zero. However, on some systems, if the section is
3807 marked as containing code and the fill value is omitted, the space is filled
3808 with no-op instructions.
3810 The third expression is also absolute, and is also optional. If it is present,
3811 it is the maximum number of bytes that should be skipped by this alignment
3812 directive. If doing the alignment would require skipping more bytes than the
3813 specified maximum, then the alignment is not done at all. You can omit the
3814 fill value (the second argument) entirely by simply using two commas after the
3815 required alignment; this can be useful if you want the alignment to be filled
3816 with no-op instructions when appropriate.
3818 The way the required alignment is specified varies from system to system.
3819 For the a29k, hppa, m68k, m88k, w65, sparc, and Hitachi SH, and i386 using ELF
3821 the first expression is the
3822 alignment request in bytes. For example @samp{.align 8} advances
3823 the location counter until it is a multiple of 8. If the location counter
3824 is already a multiple of 8, no change is needed.
3826 For other systems, including the i386 using a.out format, and the arm and
3827 strongarm, it is the
3828 number of low-order zero bits the location counter must have after
3829 advancement. For example @samp{.align 3} advances the location
3830 counter until it a multiple of 8. If the location counter is already a
3831 multiple of 8, no change is needed.
3833 This inconsistency is due to the different behaviors of the various
3834 native assemblers for these systems which GAS must emulate.
3835 GAS also provides @code{.balign} and @code{.p2align} directives,
3836 described later, which have a consistent behavior across all
3837 architectures (but are specific to GAS).
3840 @section @code{.ascii "@var{string}"}@dots{}
3842 @cindex @code{ascii} directive
3843 @cindex string literals
3844 @code{.ascii} expects zero or more string literals (@pxref{Strings})
3845 separated by commas. It assembles each string (with no automatic
3846 trailing zero byte) into consecutive addresses.
3849 @section @code{.asciz "@var{string}"}@dots{}
3851 @cindex @code{asciz} directive
3852 @cindex zero-terminated strings
3853 @cindex null-terminated strings
3854 @code{.asciz} is just like @code{.ascii}, but each string is followed by
3855 a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
3858 @section @code{.balign[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3860 @cindex padding the location counter given number of bytes
3861 @cindex @code{balign} directive
3862 Pad the location counter (in the current subsection) to a particular
3863 storage boundary. The first expression (which must be absolute) is the
3864 alignment request in bytes. For example @samp{.balign 8} advances
3865 the location counter until it is a multiple of 8. If the location counter
3866 is already a multiple of 8, no change is needed.
3868 The second expression (also absolute) gives the fill value to be stored in the
3869 padding bytes. It (and the comma) may be omitted. If it is omitted, the
3870 padding bytes are normally zero. However, on some systems, if the section is
3871 marked as containing code and the fill value is omitted, the space is filled
3872 with no-op instructions.
3874 The third expression is also absolute, and is also optional. If it is present,
3875 it is the maximum number of bytes that should be skipped by this alignment
3876 directive. If doing the alignment would require skipping more bytes than the
3877 specified maximum, then the alignment is not done at all. You can omit the
3878 fill value (the second argument) entirely by simply using two commas after the
3879 required alignment; this can be useful if you want the alignment to be filled
3880 with no-op instructions when appropriate.
3882 @cindex @code{balignw} directive
3883 @cindex @code{balignl} directive
3884 The @code{.balignw} and @code{.balignl} directives are variants of the
3885 @code{.balign} directive. The @code{.balignw} directive treats the fill
3886 pattern as a two byte word value. The @code{.balignl} directives treats the
3887 fill pattern as a four byte longword value. For example, @code{.balignw
3888 4,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
3889 filled in with the value 0x368d (the exact placement of the bytes depends upon
3890 the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
3894 @section @code{.byte @var{expressions}}
3896 @cindex @code{byte} directive
3897 @cindex integers, one byte
3898 @code{.byte} expects zero or more expressions, separated by commas.
3899 Each expression is assembled into the next byte.
3902 @section @code{.comm @var{symbol} , @var{length} }
3904 @cindex @code{comm} directive
3905 @cindex symbol, common
3906 @code{.comm} declares a common symbol named @var{symbol}. When linking, a
3907 common symbol in one object file may be merged with a defined or common symbol
3908 of the same name in another object file. If @code{@value{LD}} does not see a
3909 definition for the symbol--just one or more common symbols--then it will
3910 allocate @var{length} bytes of uninitialized memory. @var{length} must be an
3911 absolute expression. If @code{@value{LD}} sees multiple common symbols with
3912 the same name, and they do not all have the same size, it will allocate space
3913 using the largest size.
3916 When using ELF, the @code{.comm} directive takes an optional third argument.
3917 This is the desired alignment of the symbol, specified as a byte boundary (for
3918 example, an alignment of 16 means that the least significant 4 bits of the
3919 address should be zero). The alignment must be an absolute expression, and it
3920 must be a power of two. If @code{@value{LD}} allocates uninitialized memory
3921 for the common symbol, it will use the alignment when placing the symbol. If
3922 no alignment is specified, @command{@value{AS}} will set the alignment to the
3923 largest power of two less than or equal to the size of the symbol, up to a
3928 The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
3929 @samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
3933 @section @code{.data @var{subsection}}
3935 @cindex @code{data} directive
3936 @code{.data} tells @command{@value{AS}} to assemble the following statements onto the
3937 end of the data subsection numbered @var{subsection} (which is an
3938 absolute expression). If @var{subsection} is omitted, it defaults
3943 @section @code{.def @var{name}}
3945 @cindex @code{def} directive
3946 @cindex COFF symbols, debugging
3947 @cindex debugging COFF symbols
3948 Begin defining debugging information for a symbol @var{name}; the
3949 definition extends until the @code{.endef} directive is encountered.
3952 This directive is only observed when @command{@value{AS}} is configured for COFF
3953 format output; when producing @code{b.out}, @samp{.def} is recognized,
3960 @section @code{.desc @var{symbol}, @var{abs-expression}}
3962 @cindex @code{desc} directive
3963 @cindex COFF symbol descriptor
3964 @cindex symbol descriptor, COFF
3965 This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
3966 to the low 16 bits of an absolute expression.
3969 The @samp{.desc} directive is not available when @command{@value{AS}} is
3970 configured for COFF output; it is only for @code{a.out} or @code{b.out}
3971 object format. For the sake of compatibility, @command{@value{AS}} accepts
3972 it, but produces no output, when configured for COFF.
3978 @section @code{.dim}
3980 @cindex @code{dim} directive
3981 @cindex COFF auxiliary symbol information
3982 @cindex auxiliary symbol information, COFF
3983 This directive is generated by compilers to include auxiliary debugging
3984 information in the symbol table. It is only permitted inside
3985 @code{.def}/@code{.endef} pairs.
3988 @samp{.dim} is only meaningful when generating COFF format output; when
3989 @command{@value{AS}} is generating @code{b.out}, it accepts this directive but
3995 @section @code{.double @var{flonums}}
3997 @cindex @code{double} directive
3998 @cindex floating point numbers (double)
3999 @code{.double} expects zero or more flonums, separated by commas. It
4000 assembles floating point numbers.
4002 The exact kind of floating point numbers emitted depends on how
4003 @command{@value{AS}} is configured. @xref{Machine Dependencies}.
4007 On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers
4008 in @sc{ieee} format.
4013 @section @code{.eject}
4015 @cindex @code{eject} directive
4016 @cindex new page, in listings
4017 @cindex page, in listings
4018 @cindex listing control: new page
4019 Force a page break at this point, when generating assembly listings.
4022 @section @code{.else}
4024 @cindex @code{else} directive
4025 @code{.else} is part of the @command{@value{AS}} support for conditional
4026 assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section
4027 of code to be assembled if the condition for the preceding @code{.if}
4031 @section @code{.elseif}
4033 @cindex @code{elseif} directive
4034 @code{.elseif} is part of the @command{@value{AS}} support for conditional
4035 assembly; @pxref{If,,@code{.if}}. It is shorthand for beginning a new
4036 @code{.if} block that would otherwise fill the entire @code{.else} section.
4039 @section @code{.end}
4041 @cindex @code{end} directive
4042 @code{.end} marks the end of the assembly file. @command{@value{AS}} does not
4043 process anything in the file past the @code{.end} directive.
4047 @section @code{.endef}
4049 @cindex @code{endef} directive
4050 This directive flags the end of a symbol definition begun with
4054 @samp{.endef} is only meaningful when generating COFF format output; if
4055 @command{@value{AS}} is configured to generate @code{b.out}, it accepts this
4056 directive but ignores it.
4061 @section @code{.endfunc}
4062 @cindex @code{endfunc} directive
4063 @code{.endfunc} marks the end of a function specified with @code{.func}.
4066 @section @code{.endif}
4068 @cindex @code{endif} directive
4069 @code{.endif} is part of the @command{@value{AS}} support for conditional assembly;
4070 it marks the end of a block of code that is only assembled
4071 conditionally. @xref{If,,@code{.if}}.
4074 @section @code{.equ @var{symbol}, @var{expression}}
4076 @cindex @code{equ} directive
4077 @cindex assigning values to symbols
4078 @cindex symbols, assigning values to
4079 This directive sets the value of @var{symbol} to @var{expression}.
4080 It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
4083 The syntax for @code{equ} on the HPPA is
4084 @samp{@var{symbol} .equ @var{expression}}.
4088 @section @code{.equiv @var{symbol}, @var{expression}}
4089 @cindex @code{equiv} directive
4090 The @code{.equiv} directive is like @code{.equ} and @code{.set}, except that
4091 the assembler will signal an error if @var{symbol} is already defined. Note a
4092 symbol which has been referenced but not actually defined is considered to be
4095 Except for the contents of the error message, this is roughly equivalent to
4104 @section @code{.err}
4105 @cindex @code{err} directive
4106 If @command{@value{AS}} assembles a @code{.err} directive, it will print an error
4107 message and, unless the @option{-Z} option was used, it will not generate an
4108 object file. This can be used to signal error an conditionally compiled code.
4111 @section @code{.exitm}
4112 Exit early from the current macro definition. @xref{Macro}.
4115 @section @code{.extern}
4117 @cindex @code{extern} directive
4118 @code{.extern} is accepted in the source program---for compatibility
4119 with other assemblers---but it is ignored. @command{@value{AS}} treats
4120 all undefined symbols as external.
4123 @section @code{.fail @var{expression}}
4125 @cindex @code{fail} directive
4126 Generates an error or a warning. If the value of the @var{expression} is 500
4127 or more, @command{@value{AS}} will print a warning message. If the value is less
4128 than 500, @command{@value{AS}} will print an error message. The message will
4129 include the value of @var{expression}. This can occasionally be useful inside
4130 complex nested macros or conditional assembly.
4132 @ifclear no-file-dir
4134 @section @code{.file @var{string}}
4136 @cindex @code{file} directive
4137 @cindex logical file name
4138 @cindex file name, logical
4139 @code{.file} tells @command{@value{AS}} that we are about to start a new logical
4140 file. @var{string} is the new file name. In general, the filename is
4141 recognized whether or not it is surrounded by quotes @samp{"}; but if you wish
4142 to specify an empty file name, you must give the quotes--@code{""}. This
4143 statement may go away in future: it is only recognized to be compatible with
4144 old @command{@value{AS}} programs.
4146 In some configurations of @command{@value{AS}}, @code{.file} has already been
4147 removed to avoid conflicts with other assemblers. @xref{Machine Dependencies}.
4152 @section @code{.fill @var{repeat} , @var{size} , @var{value}}
4154 @cindex @code{fill} directive
4155 @cindex writing patterns in memory
4156 @cindex patterns, writing in memory
4157 @var{repeat}, @var{size} and @var{value} are absolute expressions.
4158 This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
4159 may be zero or more. @var{Size} may be zero or more, but if it is
4160 more than 8, then it is deemed to have the value 8, compatible with
4161 other people's assemblers. The contents of each @var{repeat} bytes
4162 is taken from an 8-byte number. The highest order 4 bytes are
4163 zero. The lowest order 4 bytes are @var{value} rendered in the
4164 byte-order of an integer on the computer @command{@value{AS}} is assembling for.
4165 Each @var{size} bytes in a repetition is taken from the lowest order
4166 @var{size} bytes of this number. Again, this bizarre behavior is
4167 compatible with other people's assemblers.
4169 @var{size} and @var{value} are optional.
4170 If the second comma and @var{value} are absent, @var{value} is
4171 assumed zero. If the first comma and following tokens are absent,
4172 @var{size} is assumed to be 1.
4175 @section @code{.float @var{flonums}}
4177 @cindex floating point numbers (single)
4178 @cindex @code{float} directive
4179 This directive assembles zero or more flonums, separated by commas. It
4180 has the same effect as @code{.single}.
4182 The exact kind of floating point numbers emitted depends on how
4183 @command{@value{AS}} is configured.
4184 @xref{Machine Dependencies}.
4188 On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers
4189 in @sc{ieee} format.
4194 @section @code{.func @var{name}[,@var{label}]}
4195 @cindex @code{func} directive
4196 @code{.func} emits debugging information to denote function @var{name}, and
4197 is ignored unless the file is assembled with debugging enabled.
4198 Only @samp{--gstabs} is currently supported.
4199 @var{label} is the entry point of the function and if omitted @var{name}
4200 prepended with the @samp{leading char} is used.
4201 @samp{leading char} is usually @code{_} or nothing, depending on the target.
4202 All functions are currently defined to have @code{void} return type.
4203 The function must be terminated with @code{.endfunc}.
4206 @section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
4208 @cindex @code{global} directive
4209 @cindex symbol, making visible to linker
4210 @code{.global} makes the symbol visible to @code{@value{LD}}. If you define
4211 @var{symbol} in your partial program, its value is made available to
4212 other partial programs that are linked with it. Otherwise,
4213 @var{symbol} takes its attributes from a symbol of the same name
4214 from another file linked into the same program.
4216 Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
4217 compatibility with other assemblers.
4220 On the HPPA, @code{.global} is not always enough to make it accessible to other
4221 partial programs. You may need the HPPA-only @code{.EXPORT} directive as well.
4222 @xref{HPPA Directives,, HPPA Assembler Directives}.
4227 @section @code{.hidden @var{names}}
4229 @cindex @code{.hidden} directive
4231 This one of the ELF visibility directives. The other two are
4232 @code{.internal} (@pxref{Internal,,@code{.internal}}) and
4233 @code{.protected} (@pxref{Protected,,@code{.protected}}).
4235 This directive overrides the named symbols default visibility (which is set by
4236 their binding: local, global or weak). The directive sets the visibility to
4237 @code{hidden} which means that the symbols are not visible to other components.
4238 Such symbols are always considered to be @code{protected} as well.
4242 @section @code{.hword @var{expressions}}
4244 @cindex @code{hword} directive
4245 @cindex integers, 16-bit
4246 @cindex numbers, 16-bit
4247 @cindex sixteen bit integers
4248 This expects zero or more @var{expressions}, and emits
4249 a 16 bit number for each.
4252 This directive is a synonym for @samp{.short}; depending on the target
4253 architecture, it may also be a synonym for @samp{.word}.
4257 This directive is a synonym for @samp{.short}.
4260 This directive is a synonym for both @samp{.short} and @samp{.word}.
4265 @section @code{.ident}
4267 @cindex @code{ident} directive
4268 This directive is used by some assemblers to place tags in object files.
4269 @command{@value{AS}} simply accepts the directive for source-file
4270 compatibility with such assemblers, but does not actually emit anything
4274 @section @code{.if @var{absolute expression}}
4276 @cindex conditional assembly
4277 @cindex @code{if} directive
4278 @code{.if} marks the beginning of a section of code which is only
4279 considered part of the source program being assembled if the argument
4280 (which must be an @var{absolute expression}) is non-zero. The end of
4281 the conditional section of code must be marked by @code{.endif}
4282 (@pxref{Endif,,@code{.endif}}); optionally, you may include code for the
4283 alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}).
4284 If you have several conditions to check, @code{.elseif} may be used to avoid
4285 nesting blocks if/else within each subsequent @code{.else} block.
4287 The following variants of @code{.if} are also supported:
4289 @cindex @code{ifdef} directive
4290 @item .ifdef @var{symbol}
4291 Assembles the following section of code if the specified @var{symbol}
4292 has been defined. Note a symbol which has been referenced but not yet defined
4293 is considered to be undefined.
4295 @cindex @code{ifc} directive
4296 @item .ifc @var{string1},@var{string2}
4297 Assembles the following section of code if the two strings are the same. The
4298 strings may be optionally quoted with single quotes. If they are not quoted,
4299 the first string stops at the first comma, and the second string stops at the
4300 end of the line. Strings which contain whitespace should be quoted. The
4301 string comparison is case sensitive.
4303 @cindex @code{ifeq} directive
4304 @item .ifeq @var{absolute expression}
4305 Assembles the following section of code if the argument is zero.
4307 @cindex @code{ifeqs} directive
4308 @item .ifeqs @var{string1},@var{string2}
4309 Another form of @code{.ifc}. The strings must be quoted using double quotes.
4311 @cindex @code{ifge} directive
4312 @item .ifge @var{absolute expression}
4313 Assembles the following section of code if the argument is greater than or
4316 @cindex @code{ifgt} directive
4317 @item .ifgt @var{absolute expression}
4318 Assembles the following section of code if the argument is greater than zero.
4320 @cindex @code{ifle} directive
4321 @item .ifle @var{absolute expression}
4322 Assembles the following section of code if the argument is less than or equal
4325 @cindex @code{iflt} directive
4326 @item .iflt @var{absolute expression}
4327 Assembles the following section of code if the argument is less than zero.
4329 @cindex @code{ifnc} directive
4330 @item .ifnc @var{string1},@var{string2}.
4331 Like @code{.ifc}, but the sense of the test is reversed: this assembles the
4332 following section of code if the two strings are not the same.
4334 @cindex @code{ifndef} directive
4335 @cindex @code{ifnotdef} directive
4336 @item .ifndef @var{symbol}
4337 @itemx .ifnotdef @var{symbol}
4338 Assembles the following section of code if the specified @var{symbol}
4339 has not been defined. Both spelling variants are equivalent. Note a symbol
4340 which has been referenced but not yet defined is considered to be undefined.
4342 @cindex @code{ifne} directive
4343 @item .ifne @var{absolute expression}
4344 Assembles the following section of code if the argument is not equal to zero
4345 (in other words, this is equivalent to @code{.if}).
4347 @cindex @code{ifnes} directive
4348 @item .ifnes @var{string1},@var{string2}
4349 Like @code{.ifeqs}, but the sense of the test is reversed: this assembles the
4350 following section of code if the two strings are not the same.
4354 @section @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
4356 @cindex @code{incbin} directive
4357 @cindex binary files, including
4358 The @code{incbin} directive includes @var{file} verbatim at the current
4359 location. You can control the search paths used with the @samp{-I} command-line
4360 option (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4363 The @var{skip} argument skips a number of bytes from the start of the
4364 @var{file}. The @var{count} argument indicates the maximum number of bytes to
4365 read. Note that the data is not aligned in any way, so it is the user's
4366 responsibility to make sure that proper alignment is provided both before and
4367 after the @code{incbin} directive.
4370 @section @code{.include "@var{file}"}
4372 @cindex @code{include} directive
4373 @cindex supporting files, including
4374 @cindex files, including
4375 This directive provides a way to include supporting files at specified
4376 points in your source program. The code from @var{file} is assembled as
4377 if it followed the point of the @code{.include}; when the end of the
4378 included file is reached, assembly of the original file continues. You
4379 can control the search paths used with the @samp{-I} command-line option
4380 (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4384 @section @code{.int @var{expressions}}
4386 @cindex @code{int} directive
4387 @cindex integers, 32-bit
4388 Expect zero or more @var{expressions}, of any section, separated by commas.
4389 For each expression, emit a number that, at run time, is the value of that
4390 expression. The byte order and bit size of the number depends on what kind
4391 of target the assembly is for.
4395 On the H8/500 and most forms of the H8/300, @code{.int} emits 16-bit
4396 integers. On the H8/300H and the Hitachi SH, however, @code{.int} emits
4403 @section @code{.internal @var{names}}
4405 @cindex @code{.internal} directive
4407 This one of the ELF visibility directives. The other two are
4408 @code{.hidden} (@pxref{Hidden,,@code{.hidden}}) and
4409 @code{.protected} (@pxref{Protected,,@code{.protected}}).
4411 This directive overrides the named symbols default visibility (which is set by
4412 their binding: local, global or weak). The directive sets the visibility to
4413 @code{internal} which means that the symbols are considered to be @code{hidden}
4414 (ie not visible to other components), and that some extra, processor specific
4415 processing must also be performed upon the symbols as well.
4419 @section @code{.irp @var{symbol},@var{values}}@dots{}
4421 @cindex @code{irp} directive
4422 Evaluate a sequence of statements assigning different values to @var{symbol}.
4423 The sequence of statements starts at the @code{.irp} directive, and is
4424 terminated by an @code{.endr} directive. For each @var{value}, @var{symbol} is
4425 set to @var{value}, and the sequence of statements is assembled. If no
4426 @var{value} is listed, the sequence of statements is assembled once, with
4427 @var{symbol} set to the null string. To refer to @var{symbol} within the
4428 sequence of statements, use @var{\symbol}.
4430 For example, assembling
4438 is equivalent to assembling
4447 @section @code{.irpc @var{symbol},@var{values}}@dots{}
4449 @cindex @code{irpc} directive
4450 Evaluate a sequence of statements assigning different values to @var{symbol}.
4451 The sequence of statements starts at the @code{.irpc} directive, and is
4452 terminated by an @code{.endr} directive. For each character in @var{value},
4453 @var{symbol} is set to the character, and the sequence of statements is
4454 assembled. If no @var{value} is listed, the sequence of statements is
4455 assembled once, with @var{symbol} set to the null string. To refer to
4456 @var{symbol} within the sequence of statements, use @var{\symbol}.
4458 For example, assembling
4466 is equivalent to assembling
4475 @section @code{.lcomm @var{symbol} , @var{length}}
4477 @cindex @code{lcomm} directive
4478 @cindex local common symbols
4479 @cindex symbols, local common
4480 Reserve @var{length} (an absolute expression) bytes for a local common
4481 denoted by @var{symbol}. The section and value of @var{symbol} are
4482 those of the new local common. The addresses are allocated in the bss
4483 section, so that at run-time the bytes start off zeroed. @var{Symbol}
4484 is not declared global (@pxref{Global,,@code{.global}}), so is normally
4485 not visible to @code{@value{LD}}.
4488 Some targets permit a third argument to be used with @code{.lcomm}. This
4489 argument specifies the desired alignment of the symbol in the bss section.
4493 The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
4494 @samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
4498 @section @code{.lflags}
4500 @cindex @code{lflags} directive (ignored)
4501 @command{@value{AS}} accepts this directive, for compatibility with other
4502 assemblers, but ignores it.
4504 @ifclear no-line-dir
4506 @section @code{.line @var{line-number}}
4508 @cindex @code{line} directive
4512 @section @code{.ln @var{line-number}}
4514 @cindex @code{ln} directive
4516 @cindex logical line number
4518 Change the logical line number. @var{line-number} must be an absolute
4519 expression. The next line has that logical line number. Therefore any other
4520 statements on the current line (after a statement separator character) are
4521 reported as on logical line number @var{line-number} @minus{} 1. One day
4522 @command{@value{AS}} will no longer support this directive: it is recognized only
4523 for compatibility with existing assembler programs.
4527 @emph{Warning:} In the AMD29K configuration of @value{AS}, this command is
4528 not available; use the synonym @code{.ln} in that context.
4533 @ifclear no-line-dir
4534 Even though this is a directive associated with the @code{a.out} or
4535 @code{b.out} object-code formats, @command{@value{AS}} still recognizes it
4536 when producing COFF output, and treats @samp{.line} as though it
4537 were the COFF @samp{.ln} @emph{if} it is found outside a
4538 @code{.def}/@code{.endef} pair.
4540 Inside a @code{.def}, @samp{.line} is, instead, one of the directives
4541 used by compilers to generate auxiliary symbol information for
4546 @section @code{.linkonce [@var{type}]}
4548 @cindex @code{linkonce} directive
4549 @cindex common sections
4550 Mark the current section so that the linker only includes a single copy of it.
4551 This may be used to include the same section in several different object files,
4552 but ensure that the linker will only include it once in the final output file.
4553 The @code{.linkonce} pseudo-op must be used for each instance of the section.
4554 Duplicate sections are detected based on the section name, so it should be
4557 This directive is only supported by a few object file formats; as of this
4558 writing, the only object file format which supports it is the Portable
4559 Executable format used on Windows NT.
4561 The @var{type} argument is optional. If specified, it must be one of the
4562 following strings. For example:
4566 Not all types may be supported on all object file formats.
4570 Silently discard duplicate sections. This is the default.
4573 Warn if there are duplicate sections, but still keep only one copy.
4576 Warn if any of the duplicates have different sizes.
4579 Warn if any of the duplicates do not have exactly the same contents.
4583 @section @code{.ln @var{line-number}}
4585 @cindex @code{ln} directive
4586 @ifclear no-line-dir
4587 @samp{.ln} is a synonym for @samp{.line}.
4590 Tell @command{@value{AS}} to change the logical line number. @var{line-number}
4591 must be an absolute expression. The next line has that logical
4592 line number, so any other statements on the current line (after a
4593 statement separator character @code{;}) are reported as on logical
4594 line number @var{line-number} @minus{} 1.
4597 This directive is accepted, but ignored, when @command{@value{AS}} is
4598 configured for @code{b.out}; its effect is only associated with COFF
4604 @section @code{.mri @var{val}}
4606 @cindex @code{mri} directive
4607 @cindex MRI mode, temporarily
4608 If @var{val} is non-zero, this tells @command{@value{AS}} to enter MRI mode. If
4609 @var{val} is zero, this tells @command{@value{AS}} to exit MRI mode. This change
4610 affects code assembled until the next @code{.mri} directive, or until the end
4611 of the file. @xref{M, MRI mode, MRI mode}.
4614 @section @code{.list}
4616 @cindex @code{list} directive
4617 @cindex listing control, turning on
4618 Control (in conjunction with the @code{.nolist} directive) whether or
4619 not assembly listings are generated. These two directives maintain an
4620 internal counter (which is zero initially). @code{.list} increments the
4621 counter, and @code{.nolist} decrements it. Assembly listings are
4622 generated whenever the counter is greater than zero.
4624 By default, listings are disabled. When you enable them (with the
4625 @samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
4626 the initial value of the listing counter is one.
4629 @section @code{.long @var{expressions}}
4631 @cindex @code{long} directive
4632 @code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}.
4635 @c no one seems to know what this is for or whether this description is
4636 @c what it really ought to do
4638 @section @code{.lsym @var{symbol}, @var{expression}}
4640 @cindex @code{lsym} directive
4641 @cindex symbol, not referenced in assembly
4642 @code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
4643 the hash table, ensuring it cannot be referenced by name during the
4644 rest of the assembly. This sets the attributes of the symbol to be
4645 the same as the expression value:
4647 @var{other} = @var{descriptor} = 0
4648 @var{type} = @r{(section of @var{expression})}
4649 @var{value} = @var{expression}
4652 The new symbol is not flagged as external.
4656 @section @code{.macro}
4659 The commands @code{.macro} and @code{.endm} allow you to define macros that
4660 generate assembly output. For example, this definition specifies a macro
4661 @code{sum} that puts a sequence of numbers into memory:
4664 .macro sum from=0, to=5
4673 With that definition, @samp{SUM 0,5} is equivalent to this assembly input:
4685 @item .macro @var{macname}
4686 @itemx .macro @var{macname} @var{macargs} @dots{}
4687 @cindex @code{macro} directive
4688 Begin the definition of a macro called @var{macname}. If your macro
4689 definition requires arguments, specify their names after the macro name,
4690 separated by commas or spaces. You can supply a default value for any
4691 macro argument by following the name with @samp{=@var{deflt}}. For
4692 example, these are all valid @code{.macro} statements:
4696 Begin the definition of a macro called @code{comm}, which takes no
4699 @item .macro plus1 p, p1
4700 @itemx .macro plus1 p p1
4701 Either statement begins the definition of a macro called @code{plus1},
4702 which takes two arguments; within the macro definition, write
4703 @samp{\p} or @samp{\p1} to evaluate the arguments.
4705 @item .macro reserve_str p1=0 p2
4706 Begin the definition of a macro called @code{reserve_str}, with two
4707 arguments. The first argument has a default value, but not the second.
4708 After the definition is complete, you can call the macro either as
4709 @samp{reserve_str @var{a},@var{b}} (with @samp{\p1} evaluating to
4710 @var{a} and @samp{\p2} evaluating to @var{b}), or as @samp{reserve_str
4711 ,@var{b}} (with @samp{\p1} evaluating as the default, in this case
4712 @samp{0}, and @samp{\p2} evaluating to @var{b}).
4715 When you call a macro, you can specify the argument values either by
4716 position, or by keyword. For example, @samp{sum 9,17} is equivalent to
4717 @samp{sum to=17, from=9}.
4720 @cindex @code{endm} directive
4721 Mark the end of a macro definition.
4724 @cindex @code{exitm} directive
4725 Exit early from the current macro definition.
4727 @cindex number of macros executed
4728 @cindex macros, count executed
4730 @command{@value{AS}} maintains a counter of how many macros it has
4731 executed in this pseudo-variable; you can copy that number to your
4732 output with @samp{\@@}, but @emph{only within a macro definition}.
4735 @item LOCAL @var{name} [ , @dots{} ]
4736 @emph{Warning: @code{LOCAL} is only available if you select ``alternate
4737 macro syntax'' with @samp{-a} or @samp{--alternate}.} @xref{Alternate,,
4738 Alternate macro syntax}.
4740 Generate a string replacement for each of the @var{name} arguments, and
4741 replace any instances of @var{name} in each macro expansion. The
4742 replacement string is unique in the assembly, and different for each
4743 separate macro expansion. @code{LOCAL} allows you to write macros that
4744 define symbols, without fear of conflict between separate macro expansions.
4749 @section @code{.nolist}
4751 @cindex @code{nolist} directive
4752 @cindex listing control, turning off
4753 Control (in conjunction with the @code{.list} directive) whether or
4754 not assembly listings are generated. These two directives maintain an
4755 internal counter (which is zero initially). @code{.list} increments the
4756 counter, and @code{.nolist} decrements it. Assembly listings are
4757 generated whenever the counter is greater than zero.
4760 @section @code{.octa @var{bignums}}
4762 @c FIXME: double size emitted for "octa" on i960, others? Or warn?
4763 @cindex @code{octa} directive
4764 @cindex integer, 16-byte
4765 @cindex sixteen byte integer
4766 This directive expects zero or more bignums, separated by commas. For each
4767 bignum, it emits a 16-byte integer.
4769 The term ``octa'' comes from contexts in which a ``word'' is two bytes;
4770 hence @emph{octa}-word for 16 bytes.
4773 @section @code{.org @var{new-lc} , @var{fill}}
4775 @cindex @code{org} directive
4776 @cindex location counter, advancing
4777 @cindex advancing location counter
4778 @cindex current address, advancing
4779 Advance the location counter of the current section to
4780 @var{new-lc}. @var{new-lc} is either an absolute expression or an
4781 expression with the same section as the current subsection. That is,
4782 you can't use @code{.org} to cross sections: if @var{new-lc} has the
4783 wrong section, the @code{.org} directive is ignored. To be compatible
4784 with former assemblers, if the section of @var{new-lc} is absolute,
4785 @command{@value{AS}} issues a warning, then pretends the section of @var{new-lc}
4786 is the same as the current subsection.
4788 @code{.org} may only increase the location counter, or leave it
4789 unchanged; you cannot use @code{.org} to move the location counter
4792 @c double negative used below "not undefined" because this is a specific
4793 @c reference to "undefined" (as SEG_UNKNOWN is called in this manual)
4794 @c section. doc@cygnus.com 18feb91
4795 Because @command{@value{AS}} tries to assemble programs in one pass, @var{new-lc}
4796 may not be undefined. If you really detest this restriction we eagerly await
4797 a chance to share your improved assembler.
4799 Beware that the origin is relative to the start of the section, not
4800 to the start of the subsection. This is compatible with other
4801 people's assemblers.
4803 When the location counter (of the current subsection) is advanced, the
4804 intervening bytes are filled with @var{fill} which should be an
4805 absolute expression. If the comma and @var{fill} are omitted,
4806 @var{fill} defaults to zero.
4809 @section @code{.p2align[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
4811 @cindex padding the location counter given a power of two
4812 @cindex @code{p2align} directive
4813 Pad the location counter (in the current subsection) to a particular
4814 storage boundary. The first expression (which must be absolute) is the
4815 number of low-order zero bits the location counter must have after
4816 advancement. For example @samp{.p2align 3} advances the location
4817 counter until it a multiple of 8. If the location counter is already a
4818 multiple of 8, no change is needed.
4820 The second expression (also absolute) gives the fill value to be stored in the
4821 padding bytes. It (and the comma) may be omitted. If it is omitted, the
4822 padding bytes are normally zero. However, on some systems, if the section is
4823 marked as containing code and the fill value is omitted, the space is filled
4824 with no-op instructions.
4826 The third expression is also absolute, and is also optional. If it is present,
4827 it is the maximum number of bytes that should be skipped by this alignment
4828 directive. If doing the alignment would require skipping more bytes than the
4829 specified maximum, then the alignment is not done at all. You can omit the
4830 fill value (the second argument) entirely by simply using two commas after the
4831 required alignment; this can be useful if you want the alignment to be filled
4832 with no-op instructions when appropriate.
4834 @cindex @code{p2alignw} directive
4835 @cindex @code{p2alignl} directive
4836 The @code{.p2alignw} and @code{.p2alignl} directives are variants of the
4837 @code{.p2align} directive. The @code{.p2alignw} directive treats the fill
4838 pattern as a two byte word value. The @code{.p2alignl} directives treats the
4839 fill pattern as a four byte longword value. For example, @code{.p2alignw
4840 2,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
4841 filled in with the value 0x368d (the exact placement of the bytes depends upon
4842 the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
4847 @section @code{.previous}
4849 @cindex @code{.previous} directive
4850 @cindex Section Stack
4851 This is one of the ELF section stack manipulation directives. The others are
4852 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4853 @code{.pushsection} (@pxref{PushSection}), and @code{.popsection}
4854 (@pxref{PopSection}).
4856 This directive swaps the current section (and subsection) with most recently
4857 referenced section (and subsection) prior to this one. Multiple
4858 @code{.previous} directives in a row will flip between two sections (and their
4861 In terms of the section stack, this directive swaps the current section with
4862 the top section on the section stack.
4867 @section @code{.popsection}
4869 @cindex @code{.popsection} directive
4870 @cindex Section Stack
4871 This is one of the ELF section stack manipulation directives. The others are
4872 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4873 @code{.pushsection} (@pxref{PushSection}), and @code{.previous}
4876 This directive replaces the current section (and subsection) with the top
4877 section (and subsection) on the section stack. This section is popped off the
4882 @section @code{.print @var{string}}
4884 @cindex @code{print} directive
4885 @command{@value{AS}} will print @var{string} on the standard output during
4886 assembly. You must put @var{string} in double quotes.
4890 @section @code{.protected @var{names}}
4892 @cindex @code{.protected} directive
4894 This one of the ELF visibility directives. The other two are
4895 @code{.hidden} (@pxref{Hidden}) and @code{.internal} (@pxref{Internal}).
4897 This directive overrides the named symbols default visibility (which is set by
4898 their binding: local, global or weak). The directive sets the visibility to
4899 @code{protected} which means that any references to the symbols from within the
4900 components that defines them must be resolved to the definition in that
4901 component, even if a definition in another component would normally preempt
4906 @section @code{.psize @var{lines} , @var{columns}}
4908 @cindex @code{psize} directive
4909 @cindex listing control: paper size
4910 @cindex paper size, for listings
4911 Use this directive to declare the number of lines---and, optionally, the
4912 number of columns---to use for each page, when generating listings.
4914 If you do not use @code{.psize}, listings use a default line-count
4915 of 60. You may omit the comma and @var{columns} specification; the
4916 default width is 200 columns.
4918 @command{@value{AS}} generates formfeeds whenever the specified number of
4919 lines is exceeded (or whenever you explicitly request one, using
4922 If you specify @var{lines} as @code{0}, no formfeeds are generated save
4923 those explicitly specified with @code{.eject}.
4926 @section @code{.purgem @var{name}}
4928 @cindex @code{purgem} directive
4929 Undefine the macro @var{name}, so that later uses of the string will not be
4930 expanded. @xref{Macro}.
4934 @section @code{.pushsection @var{name} , @var{subsection}}
4936 @cindex @code{.pushsection} directive
4937 @cindex Section Stack
4938 This is one of the ELF section stack manipulation directives. The others are
4939 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4940 @code{.popsection} (@pxref{PopSection}), and @code{.previous}
4943 This directive is a synonym for @code{.section}. It pushes the current section
4944 (and subsection) onto the top of the section stack, and then replaces the
4945 current section and subsection with @code{name} and @code{subsection}.
4949 @section @code{.quad @var{bignums}}
4951 @cindex @code{quad} directive
4952 @code{.quad} expects zero or more bignums, separated by commas. For
4953 each bignum, it emits
4955 an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a
4956 warning message; and just takes the lowest order 8 bytes of the bignum.
4957 @cindex eight-byte integer
4958 @cindex integer, 8-byte
4960 The term ``quad'' comes from contexts in which a ``word'' is two bytes;
4961 hence @emph{quad}-word for 8 bytes.
4964 a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
4965 warning message; and just takes the lowest order 16 bytes of the bignum.
4966 @cindex sixteen-byte integer
4967 @cindex integer, 16-byte
4971 @section @code{.rept @var{count}}
4973 @cindex @code{rept} directive
4974 Repeat the sequence of lines between the @code{.rept} directive and the next
4975 @code{.endr} directive @var{count} times.
4977 For example, assembling
4985 is equivalent to assembling
4994 @section @code{.sbttl "@var{subheading}"}
4996 @cindex @code{sbttl} directive
4997 @cindex subtitles for listings
4998 @cindex listing control: subtitle
4999 Use @var{subheading} as the title (third line, immediately after the
5000 title line) when generating assembly listings.
5002 This directive affects subsequent pages, as well as the current page if
5003 it appears within ten lines of the top of a page.
5007 @section @code{.scl @var{class}}
5009 @cindex @code{scl} directive
5010 @cindex symbol storage class (COFF)
5011 @cindex COFF symbol storage class
5012 Set the storage-class value for a symbol. This directive may only be
5013 used inside a @code{.def}/@code{.endef} pair. Storage class may flag
5014 whether a symbol is static or external, or it may record further
5015 symbolic debugging information.
5018 The @samp{.scl} directive is primarily associated with COFF output; when
5019 configured to generate @code{b.out} output format, @command{@value{AS}}
5020 accepts this directive but ignores it.
5025 @section @code{.section @var{name}} (COFF version)
5027 @cindex @code{section} directive
5028 @cindex named section
5029 Use the @code{.section} directive to assemble the following code into a section
5032 This directive is only supported for targets that actually support arbitrarily
5033 named sections; on @code{a.out} targets, for example, it is not accepted, even
5034 with a standard @code{a.out} section name.
5036 For COFF targets, the @code{.section} directive is used in one of the following
5040 .section @var{name}[, "@var{flags}"]
5041 .section @var{name}[, @var{subsegment}]
5044 If the optional argument is quoted, it is taken as flags to use for the
5045 section. Each flag is a single character. The following flags are recognized:
5048 bss section (uninitialized data)
5050 section is not loaded
5060 shared section (meaningful for PE targets)
5062 ignored. (For compatibility with the ELF version)
5065 If no flags are specified, the default flags depend upon the section name. If
5066 the section name is not recognized, the default will be for the section to be
5067 loaded and writable. Note the @code{n} and @code{w} flags remove attributes
5068 from the section, rather than adding them, so if they are used on their own it
5069 will be as if no flags had been specified at all.
5071 If the optional argument to the @code{.section} directive is not quoted, it is
5072 taken as a subsegment number (@pxref{Sub-Sections}).
5075 @section @code{.section @var{name}} (ELF version)
5077 @cindex @code{section} directive
5078 @cindex named section
5080 @cindex Section Stack
5081 This is one of the ELF section stack manipulation directives. The others are
5082 @code{.subsection} (@pxref{SubSection}), @code{.pushsection}
5083 (@pxref{PushSection}), @code{.popsection} (@pxref{PopSection}), and
5084 @code{.previous} (@pxref{Previous}).
5087 For ELF targets, the @code{.section} directive is used like this:
5090 .section @var{name} [, "@var{flags}"[, @@@var{type}[, @@@var{entsize}]]]
5093 The optional @var{flags} argument is a quoted string which may contain any
5094 combination of the following characters:
5097 section is allocatable
5101 section is executable
5103 section is mergeable
5105 section contains zero terminated strings
5108 The optional @var{type} argument may contain one of the following constants:
5111 section contains data
5113 section does not contain data (i.e., section only occupies space)
5116 Note on targets where the @code{@@} character is the start of a comment (eg
5117 ARM) then another character is used instead. For example the ARM port uses the
5120 If @var{flags} contains @code{M} flag, @var{type} argument must be specified
5121 as well as @var{entsize} argument. Sections with @code{M} flag but not
5122 @code{S} flag must contain fixed size constants, each @var{entsize} octets
5123 long. Sections with both @code{M} and @code{S} must contain zero terminated
5124 strings where each character is @var{entsize} bytes long. The linker may remove
5125 duplicates within sections with the same name, same entity size and same flags.
5127 If no flags are specified, the default flags depend upon the section name. If
5128 the section name is not recognized, the default will be for the section to have
5129 none of the above flags: it will not be allocated in memory, nor writable, nor
5130 executable. The section will contain data.
5132 For ELF targets, the assembler supports another type of @code{.section}
5133 directive for compatibility with the Solaris assembler:
5136 .section "@var{name}"[, @var{flags}...]
5139 Note that the section name is quoted. There may be a sequence of comma
5143 section is allocatable
5147 section is executable
5150 This directive replaces the current section and subsection. The replaced
5151 section and subsection are pushed onto the section stack. See the contents of
5152 the gas testsuite directory @code{gas/testsuite/gas/elf} for some examples of
5153 how this directive and the other section stack directives work.
5156 @section @code{.set @var{symbol}, @var{expression}}
5158 @cindex @code{set} directive
5159 @cindex symbol value, setting
5160 Set the value of @var{symbol} to @var{expression}. This
5161 changes @var{symbol}'s value and type to conform to
5162 @var{expression}. If @var{symbol} was flagged as external, it remains
5163 flagged (@pxref{Symbol Attributes}).
5165 You may @code{.set} a symbol many times in the same assembly.
5167 If you @code{.set} a global symbol, the value stored in the object
5168 file is the last value stored into it.
5171 The syntax for @code{set} on the HPPA is
5172 @samp{@var{symbol} .set @var{expression}}.
5176 @section @code{.short @var{expressions}}
5178 @cindex @code{short} directive
5180 @code{.short} is normally the same as @samp{.word}.
5181 @xref{Word,,@code{.word}}.
5183 In some configurations, however, @code{.short} and @code{.word} generate
5184 numbers of different lengths; @pxref{Machine Dependencies}.
5188 @code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
5191 This expects zero or more @var{expressions}, and emits
5192 a 16 bit number for each.
5197 @section @code{.single @var{flonums}}
5199 @cindex @code{single} directive
5200 @cindex floating point numbers (single)
5201 This directive assembles zero or more flonums, separated by commas. It
5202 has the same effect as @code{.float}.
5204 The exact kind of floating point numbers emitted depends on how
5205 @command{@value{AS}} is configured. @xref{Machine Dependencies}.
5209 On the @value{TARGET} family, @code{.single} emits 32-bit floating point
5210 numbers in @sc{ieee} format.
5215 @section @code{.size} (COFF version)
5217 @cindex @code{size} directive
5218 This directive is generated by compilers to include auxiliary debugging
5219 information in the symbol table. It is only permitted inside
5220 @code{.def}/@code{.endef} pairs.
5223 @samp{.size} is only meaningful when generating COFF format output; when
5224 @command{@value{AS}} is generating @code{b.out}, it accepts this directive but
5228 @section @code{.size @var{name} , @var{expression}} (ELF version)
5229 @cindex @code{size} directive
5231 This directive is used to set the size associated with a symbol @var{name}.
5232 The size in bytes is computed from @var{expression} which can make use of label
5233 arithmetic. This directive is typically used to set the size of function
5237 @section @code{.sleb128 @var{expressions}}
5239 @cindex @code{sleb128} directive
5240 @var{sleb128} stands for ``signed little endian base 128.'' This is a
5241 compact, variable length representation of numbers used by the DWARF
5242 symbolic debugging format. @xref{Uleb128,@code{.uleb128}}.
5244 @ifclear no-space-dir
5246 @section @code{.skip @var{size} , @var{fill}}
5248 @cindex @code{skip} directive
5249 @cindex filling memory
5250 This directive emits @var{size} bytes, each of value @var{fill}. Both
5251 @var{size} and @var{fill} are absolute expressions. If the comma and
5252 @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same as
5256 @section @code{.space @var{size} , @var{fill}}
5258 @cindex @code{space} directive
5259 @cindex filling memory
5260 This directive emits @var{size} bytes, each of value @var{fill}. Both
5261 @var{size} and @var{fill} are absolute expressions. If the comma
5262 and @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same
5267 @emph{Warning:} @code{.space} has a completely different meaning for HPPA
5268 targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
5269 Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the
5270 @code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives},
5279 @section @code{.space}
5280 @cindex @code{space} directive
5282 On the AMD 29K, this directive is ignored; it is accepted for
5283 compatibility with other AMD 29K assemblers.
5286 @emph{Warning:} In most versions of the @sc{gnu} assembler, the directive
5287 @code{.space} has the effect of @code{.block} @xref{Machine Dependencies}.
5293 @section @code{.stabd, .stabn, .stabs}
5295 @cindex symbolic debuggers, information for
5296 @cindex @code{stab@var{x}} directives
5297 There are three directives that begin @samp{.stab}.
5298 All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
5299 The symbols are not entered in the @command{@value{AS}} hash table: they
5300 cannot be referenced elsewhere in the source file.
5301 Up to five fields are required:
5305 This is the symbol's name. It may contain any character except
5306 @samp{\000}, so is more general than ordinary symbol names. Some
5307 debuggers used to code arbitrarily complex structures into symbol names
5311 An absolute expression. The symbol's type is set to the low 8 bits of
5312 this expression. Any bit pattern is permitted, but @code{@value{LD}}
5313 and debuggers choke on silly bit patterns.
5316 An absolute expression. The symbol's ``other'' attribute is set to the
5317 low 8 bits of this expression.
5320 An absolute expression. The symbol's descriptor is set to the low 16
5321 bits of this expression.
5324 An absolute expression which becomes the symbol's value.
5327 If a warning is detected while reading a @code{.stabd}, @code{.stabn},
5328 or @code{.stabs} statement, the symbol has probably already been created;
5329 you get a half-formed symbol in your object file. This is
5330 compatible with earlier assemblers!
5333 @cindex @code{stabd} directive
5334 @item .stabd @var{type} , @var{other} , @var{desc}
5336 The ``name'' of the symbol generated is not even an empty string.
5337 It is a null pointer, for compatibility. Older assemblers used a
5338 null pointer so they didn't waste space in object files with empty
5341 The symbol's value is set to the location counter,
5342 relocatably. When your program is linked, the value of this symbol
5343 is the address of the location counter when the @code{.stabd} was
5346 @cindex @code{stabn} directive
5347 @item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
5348 The name of the symbol is set to the empty string @code{""}.
5350 @cindex @code{stabs} directive
5351 @item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
5352 All five fields are specified.
5358 @section @code{.string} "@var{str}"
5360 @cindex string, copying to object file
5361 @cindex @code{string} directive
5363 Copy the characters in @var{str} to the object file. You may specify more than
5364 one string to copy, separated by commas. Unless otherwise specified for a
5365 particular machine, the assembler marks the end of each string with a 0 byte.
5366 You can use any of the escape sequences described in @ref{Strings,,Strings}.
5369 @section @code{.struct @var{expression}}
5371 @cindex @code{struct} directive
5372 Switch to the absolute section, and set the section offset to @var{expression},
5373 which must be an absolute expression. You might use this as follows:
5382 This would define the symbol @code{field1} to have the value 0, the symbol
5383 @code{field2} to have the value 4, and the symbol @code{field3} to have the
5384 value 8. Assembly would be left in the absolute section, and you would need to
5385 use a @code{.section} directive of some sort to change to some other section
5386 before further assembly.
5390 @section @code{.subsection @var{name}}
5392 @cindex @code{.subsection} directive
5393 @cindex Section Stack
5394 This is one of the ELF section stack manipulation directives. The others are
5395 @code{.section} (@pxref{Section}), @code{.pushsection} (@pxref{PushSection}),
5396 @code{.popsection} (@pxref{PopSection}), and @code{.previous}
5399 This directive replaces the current subsection with @code{name}. The current
5400 section is not changed. The replaced subsection is put onto the section stack
5401 in place of the then current top of stack subsection.
5406 @section @code{.symver}
5407 @cindex @code{symver} directive
5408 @cindex symbol versioning
5409 @cindex versions of symbols
5410 Use the @code{.symver} directive to bind symbols to specific version nodes
5411 within a source file. This is only supported on ELF platforms, and is
5412 typically used when assembling files to be linked into a shared library.
5413 There are cases where it may make sense to use this in objects to be bound
5414 into an application itself so as to override a versioned symbol from a
5417 For ELF targets, the @code{.symver} directive can be used like this:
5419 .symver @var{name}, @var{name2@@nodename}
5421 If the symbol @var{name} is defined within the file
5422 being assembled, the @code{.symver} directive effectively creates a symbol
5423 alias with the name @var{name2@@nodename}, and in fact the main reason that we
5424 just don't try and create a regular alias is that the @var{@@} character isn't
5425 permitted in symbol names. The @var{name2} part of the name is the actual name
5426 of the symbol by which it will be externally referenced. The name @var{name}
5427 itself is merely a name of convenience that is used so that it is possible to
5428 have definitions for multiple versions of a function within a single source
5429 file, and so that the compiler can unambiguously know which version of a
5430 function is being mentioned. The @var{nodename} portion of the alias should be
5431 the name of a node specified in the version script supplied to the linker when
5432 building a shared library. If you are attempting to override a versioned
5433 symbol from a shared library, then @var{nodename} should correspond to the
5434 nodename of the symbol you are trying to override.
5436 If the symbol @var{name} is not defined within the file being assembled, all
5437 references to @var{name} will be changed to @var{name2@@nodename}. If no
5438 reference to @var{name} is made, @var{name2@@nodename} will be removed from the
5441 Another usage of the @code{.symver} directive is:
5443 .symver @var{name}, @var{name2@@@@nodename}
5445 In this case, the symbol @var{name} must exist and be defined within
5446 the file being assembled. It is similar to @var{name2@@nodename}. The
5447 difference is @var{name2@@@@nodename} will also be used to resolve
5448 references to @var{name2} by the linker.
5450 The third usage of the @code{.symver} directive is:
5452 .symver @var{name}, @var{name2@@@@@@nodename}
5454 When @var{name} is not defined within the
5455 file being assembled, it is treated as @var{name2@@nodename}. When
5456 @var{name} is defined within the file being assembled, the symbol
5457 name, @var{name}, will be changed to @var{name2@@@@nodename}.
5462 @section @code{.tag @var{structname}}
5464 @cindex COFF structure debugging
5465 @cindex structure debugging, COFF
5466 @cindex @code{tag} directive
5467 This directive is generated by compilers to include auxiliary debugging
5468 information in the symbol table. It is only permitted inside
5469 @code{.def}/@code{.endef} pairs. Tags are used to link structure
5470 definitions in the symbol table with instances of those structures.
5473 @samp{.tag} is only used when generating COFF format output; when
5474 @command{@value{AS}} is generating @code{b.out}, it accepts this directive but
5480 @section @code{.text @var{subsection}}
5482 @cindex @code{text} directive
5483 Tells @command{@value{AS}} to assemble the following statements onto the end of
5484 the text subsection numbered @var{subsection}, which is an absolute
5485 expression. If @var{subsection} is omitted, subsection number zero
5489 @section @code{.title "@var{heading}"}
5491 @cindex @code{title} directive
5492 @cindex listing control: title line
5493 Use @var{heading} as the title (second line, immediately after the
5494 source file name and pagenumber) when generating assembly listings.
5496 This directive affects subsequent pages, as well as the current page if
5497 it appears within ten lines of the top of a page.
5500 @section @code{.type @var{int}} (COFF version)
5502 @cindex COFF symbol type
5503 @cindex symbol type, COFF
5504 @cindex @code{type} directive
5505 This directive, permitted only within @code{.def}/@code{.endef} pairs,
5506 records the integer @var{int} as the type attribute of a symbol table entry.
5509 @samp{.type} is associated only with COFF format output; when
5510 @command{@value{AS}} is configured for @code{b.out} output, it accepts this
5511 directive but ignores it.
5514 @section @code{.type @var{name} , @var{type description}} (ELF version)
5516 @cindex ELF symbol type
5517 @cindex symbol type, ELF
5518 @cindex @code{type} directive
5519 This directive is used to set the type of symbol @var{name} to be either a
5520 function symbol or an object symbol. There are five different syntaxes
5521 supported for the @var{type description} field, in order to provide
5522 compatibility with various other assemblers. The syntaxes supported are:
5525 .type <name>,#function
5526 .type <name>,#object
5528 .type <name>,@@function
5529 .type <name>,@@object
5531 .type <name>,%function
5532 .type <name>,%object
5534 .type <name>,"function"
5535 .type <name>,"object"
5537 .type <name> STT_FUNCTION
5538 .type <name> STT_OBJECT
5542 @section @code{.uleb128 @var{expressions}}
5544 @cindex @code{uleb128} directive
5545 @var{uleb128} stands for ``unsigned little endian base 128.'' This is a
5546 compact, variable length representation of numbers used by the DWARF
5547 symbolic debugging format. @xref{Sleb128,@code{.sleb128}}.
5551 @section @code{.val @var{addr}}
5553 @cindex @code{val} directive
5554 @cindex COFF value attribute
5555 @cindex value attribute, COFF
5556 This directive, permitted only within @code{.def}/@code{.endef} pairs,
5557 records the address @var{addr} as the value attribute of a symbol table
5561 @samp{.val} is used only for COFF output; when @command{@value{AS}} is
5562 configured for @code{b.out}, it accepts this directive but ignores it.
5568 @section @code{.version "@var{string}"}
5570 @cindex @code{.version}
5571 This directive creates a @code{.note} section and places into it an ELF
5572 formatted note of type NT_VERSION. The note's name is set to @code{string}.
5577 @section @code{.vtable_entry @var{table}, @var{offset}}
5579 @cindex @code{.vtable_entry}
5580 This directive finds or creates a symbol @code{table} and creates a
5581 @code{VTABLE_ENTRY} relocation for it with an addend of @code{offset}.
5584 @section @code{.vtable_inherit @var{child}, @var{parent}}
5586 @cindex @code{.vtable_inherit}
5587 This directive finds the symbol @code{child} and finds or creates the symbol
5588 @code{parent} and then creates a @code{VTABLE_INHERIT} relocation for the
5589 parent whose addend is the value of the child symbol. As a special case the
5590 parent name of @code{0} is treated as refering the @code{*ABS*} section.
5595 @section @code{.weak @var{names}}
5597 @cindex @code{.weak}
5598 This directive sets the weak attribute on the comma separated list of symbol
5599 @code{names}. If the symbols do not already exist, they will be created.
5603 @section @code{.word @var{expressions}}
5605 @cindex @code{word} directive
5606 This directive expects zero or more @var{expressions}, of any section,
5607 separated by commas.
5610 For each expression, @command{@value{AS}} emits a 32-bit number.
5613 For each expression, @command{@value{AS}} emits a 16-bit number.
5618 The size of the number emitted, and its byte order,
5619 depend on what target computer the assembly is for.
5622 @c on amd29k, i960, sparc the "special treatment to support compilers" doesn't
5623 @c happen---32-bit addressability, period; no long/short jumps.
5624 @ifset DIFF-TBL-KLUGE
5625 @cindex difference tables altered
5626 @cindex altered difference tables
5628 @emph{Warning: Special Treatment to support Compilers}
5632 Machines with a 32-bit address space, but that do less than 32-bit
5633 addressing, require the following special treatment. If the machine of
5634 interest to you does 32-bit addressing (or doesn't require it;
5635 @pxref{Machine Dependencies}), you can ignore this issue.
5638 In order to assemble compiler output into something that works,
5639 @command{@value{AS}} occasionally does strange things to @samp{.word} directives.
5640 Directives of the form @samp{.word sym1-sym2} are often emitted by
5641 compilers as part of jump tables. Therefore, when @command{@value{AS}} assembles a
5642 directive of the form @samp{.word sym1-sym2}, and the difference between
5643 @code{sym1} and @code{sym2} does not fit in 16 bits, @command{@value{AS}}
5644 creates a @dfn{secondary jump table}, immediately before the next label.
5645 This secondary jump table is preceded by a short-jump to the
5646 first byte after the secondary table. This short-jump prevents the flow
5647 of control from accidentally falling into the new table. Inside the
5648 table is a long-jump to @code{sym2}. The original @samp{.word}
5649 contains @code{sym1} minus the address of the long-jump to
5652 If there were several occurrences of @samp{.word sym1-sym2} before the
5653 secondary jump table, all of them are adjusted. If there was a
5654 @samp{.word sym3-sym4}, that also did not fit in sixteen bits, a
5655 long-jump to @code{sym4} is included in the secondary jump table,
5656 and the @code{.word} directives are adjusted to contain @code{sym3}
5657 minus the address of the long-jump to @code{sym4}; and so on, for as many
5658 entries in the original jump table as necessary.
5661 @emph{This feature may be disabled by compiling @command{@value{AS}} with the
5662 @samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse
5663 assembly language programmers.
5666 @c end DIFF-TBL-KLUGE
5669 @section Deprecated Directives
5671 @cindex deprecated directives
5672 @cindex obsolescent directives
5673 One day these directives won't work.
5674 They are included for compatibility with older assemblers.
5681 @node Machine Dependencies
5682 @chapter Machine Dependent Features
5684 @cindex machine dependencies
5685 The machine instruction sets are (almost by definition) different on
5686 each machine where @command{@value{AS}} runs. Floating point representations
5687 vary as well, and @command{@value{AS}} often supports a few additional
5688 directives or command-line options for compatibility with other
5689 assemblers on a particular platform. Finally, some versions of
5690 @command{@value{AS}} support special pseudo-instructions for branch
5693 This chapter discusses most of these differences, though it does not
5694 include details on any machine's instruction set. For details on that
5695 subject, see the hardware manufacturer's manual.
5699 * AMD29K-Dependent:: AMD 29K Dependent Features
5702 * Alpha-Dependent:: Alpha Dependent Features
5705 * ARC-Dependent:: ARC Dependent Features
5708 * ARM-Dependent:: ARM Dependent Features
5711 * CRIS-Dependent:: CRIS Dependent Features
5714 * D10V-Dependent:: D10V Dependent Features
5717 * D30V-Dependent:: D30V Dependent Features
5720 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
5723 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
5726 * HPPA-Dependent:: HPPA Dependent Features
5729 * ESA/390-Dependent:: IBM ESA/390 Dependent Features
5732 * i386-Dependent:: Intel 80386 and AMD x86-64 Dependent Features
5735 * i860-Dependent:: Intel 80860 Dependent Features
5738 * i960-Dependent:: Intel 80960 Dependent Features
5741 * IP2K-Dependent:: IP2K Dependent Features
5744 * M32R-Dependent:: M32R Dependent Features
5747 * M68K-Dependent:: M680x0 Dependent Features
5750 * M68HC11-Dependent:: M68HC11 and 68HC12 Dependent Features
5753 * M88K-Dependent:: M880x0 Dependent Features
5756 * MIPS-Dependent:: MIPS Dependent Features
5759 * MMIX-Dependent:: MMIX Dependent Features
5762 * SH-Dependent:: Hitachi SH Dependent Features
5763 * SH64-Dependent:: Hitachi SH64 Dependent Features
5766 * PDP-11-Dependent:: PDP-11 Dependent Features
5769 * PJ-Dependent:: picoJava Dependent Features
5772 * PPC-Dependent:: PowerPC Dependent Features
5775 * Sparc-Dependent:: SPARC Dependent Features
5778 * TIC54X-Dependent:: TI TMS320C54x Dependent Features
5781 * V850-Dependent:: V850 Dependent Features
5784 * Z8000-Dependent:: Z8000 Dependent Features
5787 * Vax-Dependent:: VAX Dependent Features
5794 @c The following major nodes are *sections* in the GENERIC version, *chapters*
5795 @c in single-cpu versions. This is mainly achieved by @lowersections. There is a
5796 @c peculiarity: to preserve cross-references, there must be a node called
5797 @c "Machine Dependencies". Hence the conditional nodenames in each
5798 @c major node below. Node defaulting in makeinfo requires adjacency of
5799 @c node and sectioning commands; hence the repetition of @chapter BLAH
5800 @c in both conditional blocks.
5803 @include c-a29k.texi
5807 @include c-alpha.texi
5819 @include c-cris.texi
5824 @node Machine Dependencies
5825 @chapter Machine Dependent Features
5827 The machine instruction sets are different on each Hitachi chip family,
5828 and there are also some syntax differences among the families. This
5829 chapter describes the specific @command{@value{AS}} features for each
5833 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
5834 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
5835 * SH-Dependent:: Hitachi SH Dependent Features
5842 @include c-d10v.texi
5846 @include c-d30v.texi
5850 @include c-h8300.texi
5854 @include c-h8500.texi
5858 @include c-hppa.texi
5862 @include c-i370.texi
5866 @include c-i386.texi
5870 @include c-i860.texi
5874 @include c-i960.texi
5878 @include c-ia64.texi
5882 @include c-ip2k.texi
5886 @include c-m32r.texi
5890 @include c-m68k.texi
5894 @include c-m68hc11.texi
5898 @include c-m88k.texi
5902 @include c-mips.texi
5906 @include c-mmix.texi
5910 @include c-ns32k.texi
5914 @include c-pdp11.texi
5927 @include c-sh64.texi
5931 @include c-sparc.texi
5935 @include c-tic54x.texi
5947 @include c-v850.texi
5951 @c reverse effect of @down at top of generic Machine-Dep chapter
5955 @node Reporting Bugs
5956 @chapter Reporting Bugs
5957 @cindex bugs in assembler
5958 @cindex reporting bugs in assembler
5960 Your bug reports play an essential role in making @command{@value{AS}} reliable.
5962 Reporting a bug may help you by bringing a solution to your problem, or it may
5963 not. But in any case the principal function of a bug report is to help the
5964 entire community by making the next version of @command{@value{AS}} work better.
5965 Bug reports are your contribution to the maintenance of @command{@value{AS}}.
5967 In order for a bug report to serve its purpose, you must include the
5968 information that enables us to fix the bug.
5971 * Bug Criteria:: Have you found a bug?
5972 * Bug Reporting:: How to report bugs
5976 @section Have you found a bug?
5977 @cindex bug criteria
5979 If you are not sure whether you have found a bug, here are some guidelines:
5982 @cindex fatal signal
5983 @cindex assembler crash
5984 @cindex crash of assembler
5986 If the assembler gets a fatal signal, for any input whatever, that is a
5987 @command{@value{AS}} bug. Reliable assemblers never crash.
5989 @cindex error on valid input
5991 If @command{@value{AS}} produces an error message for valid input, that is a bug.
5993 @cindex invalid input
5995 If @command{@value{AS}} does not produce an error message for invalid input, that
5996 is a bug. However, you should note that your idea of ``invalid input'' might
5997 be our idea of ``an extension'' or ``support for traditional practice''.
6000 If you are an experienced user of assemblers, your suggestions for improvement
6001 of @command{@value{AS}} are welcome in any case.
6005 @section How to report bugs
6007 @cindex assembler bugs, reporting
6009 A number of companies and individuals offer support for @sc{gnu} products. If
6010 you obtained @command{@value{AS}} from a support organization, we recommend you
6011 contact that organization first.
6013 You can find contact information for many support companies and
6014 individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
6017 In any event, we also recommend that you send bug reports for @command{@value{AS}}
6018 to @samp{bug-binutils@@gnu.org}.
6020 The fundamental principle of reporting bugs usefully is this:
6021 @strong{report all the facts}. If you are not sure whether to state a
6022 fact or leave it out, state it!
6024 Often people omit facts because they think they know what causes the problem
6025 and assume that some details do not matter. Thus, you might assume that the
6026 name of a symbol you use in an example does not matter. Well, probably it does
6027 not, but one cannot be sure. Perhaps the bug is a stray memory reference which
6028 happens to fetch from the location where that name is stored in memory;
6029 perhaps, if the name were different, the contents of that location would fool
6030 the assembler into doing the right thing despite the bug. Play it safe and
6031 give a specific, complete example. That is the easiest thing for you to do,
6032 and the most helpful.
6034 Keep in mind that the purpose of a bug report is to enable us to fix the bug if
6035 it is new to us. Therefore, always write your bug reports on the assumption
6036 that the bug has not been reported previously.
6038 Sometimes people give a few sketchy facts and ask, ``Does this ring a
6039 bell?'' Those bug reports are useless, and we urge everyone to
6040 @emph{refuse to respond to them} except to chide the sender to report
6043 To enable us to fix the bug, you should include all these things:
6047 The version of @command{@value{AS}}. @command{@value{AS}} announces it if you start
6048 it with the @samp{--version} argument.
6050 Without this, we will not know whether there is any point in looking for
6051 the bug in the current version of @command{@value{AS}}.
6054 Any patches you may have applied to the @command{@value{AS}} source.
6057 The type of machine you are using, and the operating system name and
6061 What compiler (and its version) was used to compile @command{@value{AS}}---e.g.
6065 The command arguments you gave the assembler to assemble your example and
6066 observe the bug. To guarantee you will not omit something important, list them
6067 all. A copy of the Makefile (or the output from make) is sufficient.
6069 If we were to try to guess the arguments, we would probably guess wrong
6070 and then we might not encounter the bug.
6073 A complete input file that will reproduce the bug. If the bug is observed when
6074 the assembler is invoked via a compiler, send the assembler source, not the
6075 high level language source. Most compilers will produce the assembler source
6076 when run with the @samp{-S} option. If you are using @code{@value{GCC}}, use
6077 the options @samp{-v --save-temps}; this will save the assembler source in a
6078 file with an extension of @file{.s}, and also show you exactly how
6079 @command{@value{AS}} is being run.
6082 A description of what behavior you observe that you believe is
6083 incorrect. For example, ``It gets a fatal signal.''
6085 Of course, if the bug is that @command{@value{AS}} gets a fatal signal, then we
6086 will certainly notice it. But if the bug is incorrect output, we might not
6087 notice unless it is glaringly wrong. You might as well not give us a chance to
6090 Even if the problem you experience is a fatal signal, you should still say so
6091 explicitly. Suppose something strange is going on, such as, your copy of
6092 @command{@value{AS}} is out of synch, or you have encountered a bug in the C
6093 library on your system. (This has happened!) Your copy might crash and ours
6094 would not. If you told us to expect a crash, then when ours fails to crash, we
6095 would know that the bug was not happening for us. If you had not told us to
6096 expect a crash, then we would not be able to draw any conclusion from our
6100 If you wish to suggest changes to the @command{@value{AS}} source, send us context
6101 diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p}
6102 option. Always send diffs from the old file to the new file. If you even
6103 discuss something in the @command{@value{AS}} source, refer to it by context, not
6106 The line numbers in our development sources will not match those in your
6107 sources. Your line numbers would convey no useful information to us.
6110 Here are some things that are not necessary:
6114 A description of the envelope of the bug.
6116 Often people who encounter a bug spend a lot of time investigating
6117 which changes to the input file will make the bug go away and which
6118 changes will not affect it.
6120 This is often time consuming and not very useful, because the way we
6121 will find the bug is by running a single example under the debugger
6122 with breakpoints, not by pure deduction from a series of examples.
6123 We recommend that you save your time for something else.
6125 Of course, if you can find a simpler example to report @emph{instead}
6126 of the original one, that is a convenience for us. Errors in the
6127 output will be easier to spot, running under the debugger will take
6128 less time, and so on.
6130 However, simplification is not vital; if you do not want to do this,
6131 report the bug anyway and send us the entire test case you used.
6134 A patch for the bug.
6136 A patch for the bug does help us if it is a good one. But do not omit
6137 the necessary information, such as the test case, on the assumption that
6138 a patch is all we need. We might see problems with your patch and decide
6139 to fix the problem another way, or we might not understand it at all.
6141 Sometimes with a program as complicated as @command{@value{AS}} it is very hard to
6142 construct an example that will make the program follow a certain path through
6143 the code. If you do not send us the example, we will not be able to construct
6144 one, so we will not be able to verify that the bug is fixed.
6146 And if we cannot understand what bug you are trying to fix, or why your
6147 patch should be an improvement, we will not install it. A test case will
6148 help us to understand.
6151 A guess about what the bug is or what it depends on.
6153 Such guesses are usually wrong. Even we cannot guess right about such
6154 things without first using the debugger to find the facts.
6157 @node Acknowledgements
6158 @chapter Acknowledgements
6160 If you have contributed to @command{@value{AS}} and your name isn't listed here,
6161 it is not meant as a slight. We just don't know about it. Send mail to the
6162 maintainer, and we'll correct the situation. Currently
6164 the maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}).
6166 Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any
6169 Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug
6170 information and the 68k series machines, most of the preprocessing pass, and
6171 extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}.
6173 K. Richard Pixley maintained GAS for a while, adding various enhancements and
6174 many bug fixes, including merging support for several processors, breaking GAS
6175 up to handle multiple object file format back ends (including heavy rewrite,
6176 testing, an integration of the coff and b.out back ends), adding configuration
6177 including heavy testing and verification of cross assemblers and file splits
6178 and renaming, converted GAS to strictly ANSI C including full prototypes, added
6179 support for m680[34]0 and cpu32, did considerable work on i960 including a COFF
6180 port (including considerable amounts of reverse engineering), a SPARC opcode
6181 file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know''
6182 assertions and made them work, much other reorganization, cleanup, and lint.
6184 Ken Raeburn wrote the high-level BFD interface code to replace most of the code
6185 in format-specific I/O modules.
6187 The original VMS support was contributed by David L. Kashtan. Eric Youngdale
6188 has done much work with it since.
6190 The Intel 80386 machine description was written by Eliot Dresselhaus.
6192 Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
6194 The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
6195 University and Torbjorn Granlund of the Swedish Institute of Computer Science.
6197 Keith Knowles at the Open Software Foundation wrote the original MIPS back end
6198 (@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support
6199 (which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to
6200 support a.out format.
6202 Support for the Zilog Z8k and Hitachi H8/300 and H8/500 processors (tc-z8k,
6203 tc-h8300, tc-h8500), and IEEE 695 object file format (obj-ieee), was written by
6204 Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
6205 use BFD for some low-level operations, for use with the H8/300 and AMD 29k
6208 John Gilmore built the AMD 29000 support, added @code{.include} support, and
6209 simplified the configuration of which versions accept which directives. He
6210 updated the 68k machine description so that Motorola's opcodes always produced
6211 fixed-size instructions (e.g. @code{jsr}), while synthetic instructions
6212 remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested
6213 cross-compilation support, and one bug in relaxation that took a week and
6214 required the proverbial one-bit fix.
6216 Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the
6217 68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
6218 added support for MIPS ECOFF and ELF targets, wrote the initial RS/6000 and
6219 PowerPC assembler, and made a few other minor patches.
6221 Steve Chamberlain made @command{@value{AS}} able to generate listings.
6223 Hewlett-Packard contributed support for the HP9000/300.
6225 Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM)
6226 along with a fairly extensive HPPA testsuite (for both SOM and ELF object
6227 formats). This work was supported by both the Center for Software Science at
6228 the University of Utah and Cygnus Support.
6230 Support for ELF format files has been worked on by Mark Eichin of Cygnus
6231 Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
6232 Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
6233 Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
6234 and some initial 64-bit support).
6236 Linas Vepstas added GAS support for the ESA/390 "IBM 370" architecture.
6238 Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote GAS and BFD
6239 support for openVMS/Alpha.
6241 Timothy Wall, Michael Hayes, and Greg Smart contributed to the various tic*
6244 Several engineers at Cygnus Support have also provided many small bug fixes and
6245 configuration enhancements.
6247 Many others have contributed large or small bugfixes and enhancements. If
6248 you have contributed significant work and are not mentioned on this list, and
6249 want to be, let us know. Some of the history has been lost; we are not
6250 intentionally leaving anyone out.
6252 @node GNU Free Documentation License
6253 @chapter GNU Free Documentation License
6255 GNU Free Documentation License
6257 Version 1.1, March 2000
6259 Copyright (C) 2000 Free Software Foundation, Inc.
6260 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
6262 Everyone is permitted to copy and distribute verbatim copies
6263 of this license document, but changing it is not allowed.
6268 The purpose of this License is to make a manual, textbook, or other
6269 written document "free" in the sense of freedom: to assure everyone
6270 the effective freedom to copy and redistribute it, with or without
6271 modifying it, either commercially or noncommercially. Secondarily,
6272 this License preserves for the author and publisher a way to get
6273 credit for their work, while not being considered responsible for
6274 modifications made by others.
6276 This License is a kind of "copyleft", which means that derivative
6277 works of the document must themselves be free in the same sense. It
6278 complements the GNU General Public License, which is a copyleft
6279 license designed for free software.
6281 We have designed this License in order to use it for manuals for free
6282 software, because free software needs free documentation: a free
6283 program should come with manuals providing the same freedoms that the
6284 software does. But this License is not limited to software manuals;
6285 it can be used for any textual work, regardless of subject matter or
6286 whether it is published as a printed book. We recommend this License
6287 principally for works whose purpose is instruction or reference.
6290 1. APPLICABILITY AND DEFINITIONS
6292 This License applies to any manual or other work that contains a
6293 notice placed by the copyright holder saying it can be distributed
6294 under the terms of this License. The "Document", below, refers to any
6295 such manual or work. Any member of the public is a licensee, and is
6298 A "Modified Version" of the Document means any work containing the
6299 Document or a portion of it, either copied verbatim, or with
6300 modifications and/or translated into another language.
6302 A "Secondary Section" is a named appendix or a front-matter section of
6303 the Document that deals exclusively with the relationship of the
6304 publishers or authors of the Document to the Document's overall subject
6305 (or to related matters) and contains nothing that could fall directly
6306 within that overall subject. (For example, if the Document is in part a
6307 textbook of mathematics, a Secondary Section may not explain any
6308 mathematics.) The relationship could be a matter of historical
6309 connection with the subject or with related matters, or of legal,
6310 commercial, philosophical, ethical or political position regarding
6313 The "Invariant Sections" are certain Secondary Sections whose titles
6314 are designated, as being those of Invariant Sections, in the notice
6315 that says that the Document is released under this License.
6317 The "Cover Texts" are certain short passages of text that are listed,
6318 as Front-Cover Texts or Back-Cover Texts, in the notice that says that
6319 the Document is released under this License.
6321 A "Transparent" copy of the Document means a machine-readable copy,
6322 represented in a format whose specification is available to the
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6326 drawing editor, and that is suitable for input to text formatters or
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6328 to text formatters. A copy made in an otherwise Transparent file
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6333 Examples of suitable formats for Transparent copies include plain
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6340 machine-generated HTML produced by some word processors for output
6343 The "Title Page" means, for a printed book, the title page itself,
6344 plus such following pages as are needed to hold, legibly, the material
6345 this License requires to appear in the title page. For works in
6346 formats which do not have any title page as such, "Title Page" means
6347 the text near the most prominent appearance of the work's title,
6348 preceding the beginning of the body of the text.
6353 You may copy and distribute the Document in any medium, either
6354 commercially or noncommercially, provided that this License, the
6355 copyright notices, and the license notice saying this License applies
6356 to the Document are reproduced in all copies, and that you add no other
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6358 technical measures to obstruct or control the reading or further
6359 copying of the copies you make or distribute. However, you may accept
6360 compensation in exchange for copies. If you distribute a large enough
6361 number of copies you must also follow the conditions in section 3.
6363 You may also lend copies, under the same conditions stated above, and
6364 you may publicly display copies.
6367 3. COPYING IN QUANTITY
6369 If you publish printed copies of the Document numbering more than 100,
6370 and the Document's license notice requires Cover Texts, you must enclose
6371 the copies in covers that carry, clearly and legibly, all these Cover
6372 Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
6373 the back cover. Both covers must also clearly and legibly identify
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6377 Copying with changes limited to the covers, as long as they preserve
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6381 If the required texts for either cover are too voluminous to fit
6382 legibly, you should put the first ones listed (as many as fit
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6386 If you publish or distribute Opaque copies of the Document numbering
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6391 general network-using public has access to download anonymously at no
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6400 It is requested, but not required, that you contact the authors of the
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6402 them a chance to provide you with an updated version of the Document.
6407 You may copy and distribute a Modified Version of the Document under
6408 the conditions of sections 2 and 3 above, provided that you release
6409 the Modified Version under precisely this License, with the Modified
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6414 A. Use in the Title Page (and on the covers, if any) a title distinct
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6419 B. List on the Title Page, as authors, one or more persons or entities
6420 responsible for authorship of the modifications in the Modified
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6425 D. Preserve all the copyright notices of the Document.
6426 E. Add an appropriate copyright notice for your modifications
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6428 F. Include, immediately after the copyright notices, a license notice
6429 giving the public permission to use the Modified Version under the
6430 terms of this License, in the form shown in the Addendum below.
6431 G. Preserve in that license notice the full lists of Invariant Sections
6432 and required Cover Texts given in the Document's license notice.
6433 H. Include an unaltered copy of this License.
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6435 it an item stating at least the title, year, new authors, and
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6437 there is no section entitled "History" in the Document, create one
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6441 J. Preserve the network location, if any, given in the Document for
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6448 K. In any section entitled "Acknowledgements" or "Dedications",
6449 preserve the section's title, and preserve in the section all the
6450 substance and tone of each of the contributor acknowledgements
6451 and/or dedications given therein.
6452 L. Preserve all the Invariant Sections of the Document,
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6454 or the equivalent are not considered part of the section titles.
6455 M. Delete any section entitled "Endorsements". Such a section
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6458 or to conflict in title with any Invariant Section.
6460 If the Modified Version includes new front-matter sections or
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6464 list of Invariant Sections in the Modified Version's license notice.
6465 These titles must be distinct from any other section titles.
6467 You may add a section entitled "Endorsements", provided it contains
6468 nothing but endorsements of your Modified Version by various
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6470 been approved by an organization as the authoritative definition of a
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6483 The author(s) and publisher(s) of the Document do not by this License
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6488 5. COMBINING DOCUMENTS
6490 You may combine the Document with other documents released under this
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6493 Invariant Sections of all of the original documents, unmodified, and
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6503 Make the same adjustment to the section titles in the list of
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6506 In the combination, you must combine any sections entitled "History"
6507 in the various original documents, forming one section entitled
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6510 entitled "Endorsements."
6513 6. COLLECTIONS OF DOCUMENTS
6515 You may make a collection consisting of the Document and other documents
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6521 You may extract a single document from such a collection, and distribute
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6524 other respects regarding verbatim copying of that document.
6527 7. AGGREGATION WITH INDEPENDENT WORKS
6529 A compilation of the Document or its derivatives with other separate
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6531 distribution medium, does not as a whole count as a Modified Version
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6533 compilation. Such a compilation is called an "aggregate", and this
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6547 Translation is considered a kind of modification, so you may
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6552 original versions of these Invariant Sections. You may include a
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6561 You may not copy, modify, sublicense, or distribute the Document except
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6563 copy, modify, sublicense or distribute the Document is void, and will
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6565 parties who have received copies, or rights, from you under this
6566 License will not have their licenses terminated so long as such
6567 parties remain in full compliance.
6570 10. FUTURE REVISIONS OF THIS LICENSE
6572 The Free Software Foundation may publish new, revised versions
6573 of the GNU Free Documentation License from time to time. Such new
6574 versions will be similar in spirit to the present version, but may
6575 differ in detail to address new problems or concerns. See
6576 http://www.gnu.org/copyleft/.
6578 Each version of the License is given a distinguishing version number.
6579 If the Document specifies that a particular numbered version of this
6580 License "or any later version" applies to it, you have the option of
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6582 of any later version that has been published (not as a draft) by the
6583 Free Software Foundation. If the Document does not specify a version
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6585 as a draft) by the Free Software Foundation.
6588 ADDENDUM: How to use this License for your documents
6590 To use this License in a document you have written, include a copy of
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6595 Copyright (c) YEAR YOUR NAME.
6596 Permission is granted to copy, distribute and/or modify this document
6597 under the terms of the GNU Free Documentation License, Version 1.1
6598 or any later version published by the Free Software Foundation;
6599 with the Invariant Sections being LIST THEIR TITLES, with the
6600 Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
6601 A copy of the license is included in the section entitled "GNU
6602 Free Documentation License".
6605 If you have no Invariant Sections, write "with no Invariant Sections"
6606 instead of saying which ones are invariant. If you have no
6607 Front-Cover Texts, write "no Front-Cover Texts" instead of
6608 "Front-Cover Texts being LIST"; likewise for Back-Cover Texts.
6610 If your document contains nontrivial examples of program code, we
6611 recommend releasing these examples in parallel under your choice of
6612 free software license, such as the GNU General Public License,
6613 to permit their use in free software.
projects / external / binutils.git / blob