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
60 @c common OR combinations of conditions
80 @set abnormal-separator
84 @settitle Using @value{AS}
87 @settitle Using @value{AS} (@value{TARGET})
89 @setchapternewpage odd
94 @c WARE! Some of the machine-dependent sections contain tables of machine
95 @c instructions. Except in multi-column format, these tables look silly.
96 @c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so
97 @c the multi-col format is faked within @example sections.
99 @c Again unfortunately, the natural size that fits on a page, for these tables,
100 @c is different depending on whether or not smallbook is turned on.
101 @c This matters, because of order: text flow switches columns at each page
104 @c The format faked in this source works reasonably well for smallbook,
105 @c not well for the default large-page format. This manual expects that if you
106 @c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the
107 @c tables in question. You can turn on one without the other at your
108 @c discretion, of course.
111 @c the insn tables look just as silly in info files regardless of smallbook,
112 @c might as well show 'em anyways.
118 * As: (as). The GNU assembler.
127 This file documents the GNU Assembler "@value{AS}".
129 @c man begin COPYRIGHT
130 Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 Free Software Foundation, Inc.
132 Permission is granted to copy, distribute and/or modify this document
133 under the terms of the GNU Free Documentation License, Version 1.1
134 or any later version published by the Free Software Foundation;
135 with no Invariant Sections, with no Front-Cover Texts, and with no
136 Back-Cover Texts. A copy of the license is included in the
137 section entitled "GNU Free Documentation License".
142 Permission is granted to process this file through Tex and print the
143 results, provided the printed document carries copying permission
144 notice identical to this one except for the removal of this paragraph
145 (this paragraph not being relevant to the printed manual).
151 @title Using @value{AS}
152 @subtitle The @sc{gnu} Assembler
154 @subtitle for the @value{TARGET} family
157 @subtitle Version @value{VERSION}
160 The Free Software Foundation Inc. thanks The Nice Computer
161 Company of Australia for loaning Dean Elsner to write the
162 first (Vax) version of @command{as} for Project @sc{gnu}.
163 The proprietors, management and staff of TNCCA thank FSF for
164 distracting the boss while they got some work
167 @author Dean Elsner, Jay Fenlason & friends
171 \hfill {\it Using {\tt @value{AS}}}\par
172 \hfill Edited by Cygnus Support\par
174 %"boxit" macro for figures:
175 %Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3)
176 \gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt
177 \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil
178 #2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline
179 \gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box
182 @vskip 0pt plus 1filll
183 Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 Free Software Foundation, Inc.
185 Permission is granted to copy, distribute and/or modify this document
186 under the terms of the GNU Free Documentation License, Version 1.1
187 or any later version published by the Free Software Foundation;
188 with no Invariant Sections, with no Front-Cover Texts, and with no
189 Back-Cover Texts. A copy of the license is included in the
190 section entitled "GNU Free Documentation License".
196 @top Using @value{AS}
198 This file is a user guide to the @sc{gnu} assembler @command{@value{AS}} version
201 This version of the file describes @command{@value{AS}} configured to generate
202 code for @value{TARGET} architectures.
205 This document is distributed under the terms of the GNU Free
206 Documentation License. A copy of the license is included in the
207 section entitled "GNU Free Documentation License".
210 * Overview:: Overview
211 * Invoking:: Command-Line Options
213 * Sections:: Sections and Relocation
215 * Expressions:: Expressions
216 * Pseudo Ops:: Assembler Directives
217 * Machine Dependencies:: Machine Dependent Features
218 * Reporting Bugs:: Reporting Bugs
219 * Acknowledgements:: Who Did What
220 * GNU Free Documentation License:: GNU Free Documentation License
228 This manual is a user guide to the @sc{gnu} assembler @command{@value{AS}}.
230 This version of the manual describes @command{@value{AS}} configured to generate
231 code for @value{TARGET} architectures.
235 @cindex invocation summary
236 @cindex option summary
237 @cindex summary of options
238 Here is a brief summary of how to invoke @command{@value{AS}}. For details,
239 @pxref{Invoking,,Comand-Line Options}.
241 @c man title AS the portable GNU assembler.
245 gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}.
249 @c We don't use deffn and friends for the following because they seem
250 @c to be limited to one line for the header.
252 @c man begin SYNOPSIS
253 @value{AS} [@b{-a}[@b{cdhlns}][=@var{file}]] [@b{-D}] [@b{--defsym} @var{sym}=@var{val}]
254 [@b{-f}] [@b{--gstabs}] [@b{--gdwarf2}] [@b{--help}] [@b{-I} @var{dir}]
255 [@b{-J}] [@b{-K}] [@b{-L}]
256 [@b{--listing-lhs-width}=@var{NUM}] [@b{--listing-lhs-width2}=@var{NUM}]
257 [@b{--listing-rhs-width}=@var{NUM}] [@b{--listing-cont-lines}=@var{NUM}]
258 [@b{--keep-locals}] [@b{-o} @var{objfile}] [@b{-R}] [@b{--statistics}] [@b{-v}]
259 [@b{-version}] [@b{--version}] [@b{-W}] [@b{--warn}] [@b{--fatal-warnings}]
260 [@b{-w}] [@b{-x}] [@b{-Z}] [@b{--target-help}] [@var{target-options}]
261 [@b{--}|@var{files} @dots{}]
263 @c Target dependent options are listed below. Keep the list sorted.
264 @c Add an empty line for separation.
266 @c am29k has no machine-dependent assembler options
270 @emph{Target ARC options:}
276 @emph{Target ARM options:}
277 @c Don't document the deprecated options
278 [@b{-mcpu}=@var{processor}[+@var{extension}@dots]]
279 [@b{-march}=@var{architecture}[+@var{extension}@dots]]
280 [@b{-mfpu}=@var{floating-point-fromat}]
283 [@b{-mapcs-32}|@b{-mapcs-26}|@b{-mapcs-float}|
284 @b{-mapcs-reentrant}]
285 [@b{-mthumb-interwork}] [@b{-moabi}] [@b{-k}]
289 @emph{Target D10V options:}
294 @emph{Target D30V options:}
295 [@b{-O}|@b{-n}|@b{-N}]
298 @c Hitachi family chips have no machine-dependent assembler options
301 @c HPPA has no machine-dependent assembler options (yet).
305 @emph{Target i386 options:}
310 @emph{Target i960 options:}
311 @c see md_parse_option in tc-i960.c
312 [@b{-ACA}|@b{-ACA_A}|@b{-ACB}|@b{-ACC}|@b{-AKA}|@b{-AKB}|
314 [@b{-b}] [@b{-no-relax}]
318 @emph{Target M32R options:}
319 [@b{--m32rx}|@b{--[no-]warn-explicit-parallel-conflicts}|
324 @emph{Target M680X0 options:}
325 [@b{-l}] [@b{-m68000}|@b{-m68010}|@b{-m68020}|@dots{}]
329 @emph{Target M68HC11 options:}
330 [@b{-m68hc11}|@b{-m68hc12}]
331 [@b{--force-long-branchs}] [@b{--short-branchs}]
332 [@b{--strict-direct-mode}] [@b{--print-insn-syntax}]
333 [@b{--print-opcodes}] [@b{--generate-example}]
337 @emph{Target MCORE options:}
338 [@b{-jsri2bsr}] [@b{-sifilter}] [@b{-relax}]
339 [@b{-mcpu=[210|340]}]
343 @emph{Target MIPS options:}
344 [@b{-nocpp}] [@b{-EL}] [@b{-EB}] [@b{-G} @var{num}] [@b{-mcpu}=@var{CPU} ]
345 [@b{-mips1}] [@b{-mips2}] [@b{-mips3}] [@b{-mips4}] [@b{-mips5}]
346 [@b{-mips32}] [@b{-mips64}]
347 [@b{-m4650}] [@b{-no-m4650}]
348 [@b{--trap}] [@b{--break}] [@b{-n}]
349 [@b{--emulation}=@var{name} ]
353 @emph{Target MMIX options:}
354 [@b{--fixed-special-register-names}] [@b{--globalize-symbols}]
355 [@b{--gnu-syntax}] [@b{--relax}] [@b{--no-predefined-symbols}]
356 [@b{--no-expand}] [@b{--no-merge-gregs}] [@b{-x}]
360 @emph{Target PDP11 options:}
361 [@b{-mpic}|@b{-mno-pic}] [@b{-mall}] [@b{-mno-extensions}]
362 [@b{-m}@var{extension}|@b{-mno-}@var{extension}]
363 [@b{-m}@var{cpu}] [@b{-m}@var{machine}]
367 @emph{Target picoJava options:}
372 @emph{Target PowerPC options:}
373 [@b{-mpwrx}|@b{-mpwr2}|@b{-mpwr}|@b{-m601}|@b{-mppc}|@b{-mppc32}|@b{-m603}|@b{-m604}|
374 @b{-m403}|@b{-m405}|@b{-mppc64}|@b{-m620}|@b{-mppc64bridge}|@b{-mbooke}|
375 @b{-mbooke32}|@b{-mbooke64}]
376 [@b{-mcom}|@b{-many}|@b{-maltivec}] [@b{-memb}]
377 [@b{-mregnames}|@b{-mno-regnames}]
378 [@b{-mrelocatable}|@b{-mrelocatable-lib}]
379 [@b{-mlittle}|@b{-mlittle-endian}|@b{-mbig}|@b{-mbig-endian}]
380 [@b{-msolaris}|@b{-mno-solaris}]
384 @emph{Target SPARC options:}
385 @c The order here is important. See c-sparc.texi.
386 [@b{-Av6}|@b{-Av7}|@b{-Av8}|@b{-Asparclet}|@b{-Asparclite}
387 @b{-Av8plus}|@b{-Av8plusa}|@b{-Av9}|@b{-Av9a}]
388 [@b{-xarch=v8plus}|@b{-xarch=v8plusa}] [@b{-bump}]
393 @emph{Target TIC54X options:}
394 [@b{-mcpu=54[123589]}|@b{-mcpu=54[56]lp}] [@b{-mfar-mode}|@b{-mf}]
395 [@b{-merrors-to-file} @var{<filename>}|@b{-me} @var{<filename>}]
398 @c Z8000 has no machine-dependent assembler options
407 Turn on listings, in any of a variety of ways:
411 omit false conditionals
414 omit debugging directives
417 include high-level source
423 include macro expansions
426 omit forms processing
432 set the name of the listing file
435 You may combine these options; for example, use @samp{-aln} for assembly
436 listing without forms processing. The @samp{=file} option, if used, must be
437 the last one. By itself, @samp{-a} defaults to @samp{-ahls}.
440 Ignored. This option is accepted for script compatibility with calls to
443 @item --defsym @var{sym}=@var{value}
444 Define the symbol @var{sym} to be @var{value} before assembling the input file.
445 @var{value} must be an integer constant. As in C, a leading @samp{0x}
446 indicates a hexadecimal value, and a leading @samp{0} indicates an octal value.
449 ``fast''---skip whitespace and comment preprocessing (assume source is
453 Generate stabs debugging information for each assembler line. This
454 may help debugging assembler code, if the debugger can handle it.
457 Generate DWARF2 debugging information for each assembler line. This
458 may help debugging assembler code, if the debugger can handle it. Note - this
459 option is only supported by some targets, not all of them.
462 Print a summary of the command line options and exit.
465 Print a summary of all target specific options and exit.
468 Add directory @var{dir} to the search list for @code{.include} directives.
471 Don't warn about signed overflow.
474 @ifclear DIFF-TBL-KLUGE
475 This option is accepted but has no effect on the @value{TARGET} family.
477 @ifset DIFF-TBL-KLUGE
478 Issue warnings when difference tables altered for long displacements.
483 Keep (in the symbol table) local symbols. On traditional a.out systems
484 these start with @samp{L}, but different systems have different local
487 @item --listing-lhs-width=@var{number}
488 Set the maximum width, in words, of the output data column for an assembler
489 listing to @var{number}.
491 @item --listing-lhs-width2=@var{number}
492 Set the maximum width, in words, of the output data column for continuation
493 lines in an assembler listing to @var{number}.
495 @item --listing-rhs-width=@var{number}
496 Set the maximum width of an input source line, as displayed in a listing, to
499 @item --listing-cont-lines=@var{number}
500 Set the maximum number of lines printed in a listing for a single line of input
503 @item -o @var{objfile}
504 Name the object-file output from @command{@value{AS}} @var{objfile}.
507 Fold the data section into the text section.
510 Print the maximum space (in bytes) and total time (in seconds) used by
513 @item --strip-local-absolute
514 Remove local absolute symbols from the outgoing symbol table.
518 Print the @command{as} version.
521 Print the @command{as} version and exit.
525 Suppress warning messages.
527 @item --fatal-warnings
528 Treat warnings as errors.
531 Don't suppress warning messages or treat them as errors.
540 Generate an object file even after errors.
542 @item -- | @var{files} @dots{}
543 Standard input, or source files to assemble.
548 The following options are available when @value{AS} is configured for
553 This option selects the core processor variant.
555 Select either big-endian (-EB) or little-endian (-EL) output.
560 The following options are available when @value{AS} is configured for the ARM
564 @item -mcpu=@var{processor}[+@var{extension}@dots]
565 Specify which ARM processor variant is the target.
566 @item -march=@var{architecture}[+@var{extension}@dots]
567 Specify which ARM architecture variant is used by the target.
568 @item -mfpu=@var{floating-point-format}
569 Select which Floating Point architecture is the target.
571 Enable Thumb only instruction decoding.
572 @item -mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant | -moabi
573 Select which procedure calling convention is in use.
575 Select either big-endian (-EB) or little-endian (-EL) output.
576 @item -mthumb-interwork
577 Specify that the code has been generated with interworking between Thumb and
580 Specify that PIC code has been generated.
585 The following options are available when @value{AS} is configured for
588 @cindex D10V optimization
589 @cindex optimization, D10V
591 Optimize output by parallelizing instructions.
596 The following options are available when @value{AS} is configured for a D30V
599 @cindex D30V optimization
600 @cindex optimization, D30V
602 Optimize output by parallelizing instructions.
606 Warn when nops are generated.
608 @cindex D30V nops after 32-bit multiply
610 Warn when a nop after a 32-bit multiply instruction is generated.
615 The following options are available when @value{AS} is configured for the
616 Intel 80960 processor.
619 @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
620 Specify which variant of the 960 architecture is the target.
623 Add code to collect statistics about branches taken.
626 Do not alter compare-and-branch instructions for long displacements;
633 The following options are available when @value{AS} is configured for the
634 Mitsubishi M32R series.
639 Specify which processor in the M32R family is the target. The default
640 is normally the M32R, but this option changes it to the M32RX.
642 @item --warn-explicit-parallel-conflicts or --Wp
643 Produce warning messages when questionable parallel constructs are
646 @item --no-warn-explicit-parallel-conflicts or --Wnp
647 Do not produce warning messages when questionable parallel constructs are
654 The following options are available when @value{AS} is configured for the
655 Motorola 68000 series.
660 Shorten references to undefined symbols, to one word instead of two.
662 @item -m68000 | -m68008 | -m68010 | -m68020 | -m68030
663 @itemx | -m68040 | -m68060 | -m68302 | -m68331 | -m68332
664 @itemx | -m68333 | -m68340 | -mcpu32 | -m5200
665 Specify what processor in the 68000 family is the target. The default
666 is normally the 68020, but this can be changed at configuration time.
668 @item -m68881 | -m68882 | -mno-68881 | -mno-68882
669 The target machine does (or does not) have a floating-point coprocessor.
670 The default is to assume a coprocessor for 68020, 68030, and cpu32. Although
671 the basic 68000 is not compatible with the 68881, a combination of the
672 two can be specified, since it's possible to do emulation of the
673 coprocessor instructions with the main processor.
675 @item -m68851 | -mno-68851
676 The target machine does (or does not) have a memory-management
677 unit coprocessor. The default is to assume an MMU for 68020 and up.
684 For details about the PDP-11 machine dependent features options,
685 see @ref{PDP-11-Options}.
688 @item -mpic | -mno-pic
689 Generate position-independent (or position-dependent) code. The
690 default is @option{-mpic}.
693 @itemx -mall-extensions
694 Enable all instruction set extensions. This is the default.
696 @item -mno-extensions
697 Disable all instruction set extensions.
699 @item -m@var{extension} | -mno-@var{extension}
700 Enable (or disable) a particular instruction set extension.
703 Enable the instruction set extensions supported by a particular CPU, and
704 disable all other extensions.
706 @item -m@var{machine}
707 Enable the instruction set extensions supported by a particular machine
708 model, and disable all other extensions.
714 The following options are available when @value{AS} is configured for
715 a picoJava processor.
719 @cindex PJ endianness
720 @cindex endianness, PJ
721 @cindex big endian output, PJ
723 Generate ``big endian'' format output.
725 @cindex little endian output, PJ
727 Generate ``little endian'' format output.
733 The following options are available when @value{AS} is configured for the
734 Motorola 68HC11 or 68HC12 series.
738 @item -m68hc11 | -m68hc12
739 Specify what processor is the target. The default is
740 defined by the configuration option when building the assembler.
742 @item --force-long-branchs
743 Relative branches are turned into absolute ones. This concerns
744 conditional branches, unconditional branches and branches to a
747 @item -S | --short-branchs
748 Do not turn relative branchs into absolute ones
749 when the offset is out of range.
751 @item --strict-direct-mode
752 Do not turn the direct addressing mode into extended addressing mode
753 when the instruction does not support direct addressing mode.
755 @item --print-insn-syntax
756 Print the syntax of instruction in case of error.
758 @item --print-opcodes
759 print the list of instructions with syntax and then exit.
761 @item --generate-example
762 print an example of instruction for each possible instruction and then exit.
763 This option is only useful for testing @command{@value{AS}}.
769 The following options are available when @command{@value{AS}} is configured
770 for the SPARC architecture:
773 @item -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite
774 @itemx -Av8plus | -Av8plusa | -Av9 | -Av9a
775 Explicitly select a variant of the SPARC architecture.
777 @samp{-Av8plus} and @samp{-Av8plusa} select a 32 bit environment.
778 @samp{-Av9} and @samp{-Av9a} select a 64 bit environment.
780 @samp{-Av8plusa} and @samp{-Av9a} enable the SPARC V9 instruction set with
781 UltraSPARC extensions.
783 @item -xarch=v8plus | -xarch=v8plusa
784 For compatibility with the Solaris v9 assembler. These options are
785 equivalent to -Av8plus and -Av8plusa, respectively.
788 Warn when the assembler switches to another architecture.
793 The following options are available when @value{AS} is configured for the 'c54x
798 Enable extended addressing mode. All addresses and relocations will assume
799 extended addressing (usually 23 bits).
800 @item -mcpu=@var{CPU_VERSION}
801 Sets the CPU version being compiled for.
802 @item -merrors-to-file @var{FILENAME}
803 Redirect error output to a file, for broken systems which don't support such
804 behaviour in the shell.
809 The following options are available when @value{AS} is configured for
814 This option sets the largest size of an object that can be referenced
815 implicitly with the @code{gp} register. It is only accepted for targets that
816 use ECOFF format, such as a DECstation running Ultrix. The default value is 8.
818 @cindex MIPS endianness
819 @cindex endianness, MIPS
820 @cindex big endian output, MIPS
822 Generate ``big endian'' format output.
824 @cindex little endian output, MIPS
826 Generate ``little endian'' format output.
835 Generate code for a particular MIPS Instruction Set Architecture level.
836 @samp{-mips1} corresponds to the @sc{r2000} and @sc{r3000} processors,
837 @samp{-mips2} to the @sc{r6000} processor, and @samp{-mips3} to the @sc{r4000}
839 @samp{-mips5}, @samp{-mips32}, and @samp{-mips64} correspond
840 to generic @sc{MIPS V}, @sc{MIPS32}, and @sc{MIPS64} ISA
841 processors, respectively.
845 Generate code for the MIPS @sc{r4650} chip. This tells the assembler to accept
846 the @samp{mad} and @samp{madu} instruction, and to not schedule @samp{nop}
847 instructions around accesses to the @samp{HI} and @samp{LO} registers.
848 @samp{-no-m4650} turns off this option.
850 @item -mcpu=@var{CPU}
851 Generate code for a particular MIPS cpu. It is exactly equivalent to
852 @samp{-m@var{cpu}}, except that there are more value of @var{cpu}
856 @item --emulation=@var{name}
857 This option causes @command{@value{AS}} to emulate @command{@value{AS}} configured
858 for some other target, in all respects, including output format (choosing
859 between ELF and ECOFF only), handling of pseudo-opcodes which may generate
860 debugging information or store symbol table information, and default
861 endianness. The available configuration names are: @samp{mipsecoff},
862 @samp{mipself}, @samp{mipslecoff}, @samp{mipsbecoff}, @samp{mipslelf},
863 @samp{mipsbelf}. The first two do not alter the default endianness from that
864 of the primary target for which the assembler was configured; the others change
865 the default to little- or big-endian as indicated by the @samp{b} or @samp{l}
866 in the name. Using @samp{-EB} or @samp{-EL} will override the endianness
867 selection in any case.
869 This option is currently supported only when the primary target
870 @command{@value{AS}} is configured for is a MIPS ELF or ECOFF target.
871 Furthermore, the primary target or others specified with
872 @samp{--enable-targets=@dots{}} at configuration time must include support for
873 the other format, if both are to be available. For example, the Irix 5
874 configuration includes support for both.
876 Eventually, this option will support more configurations, with more
877 fine-grained control over the assembler's behavior, and will be supported for
881 @command{@value{AS}} ignores this option. It is accepted for compatibility with
889 Control how to deal with multiplication overflow and division by zero.
890 @samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception
891 (and only work for Instruction Set Architecture level 2 and higher);
892 @samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a
896 When this option is used, @command{@value{AS}} will issue a warning every
897 time it generates a nop instruction from a macro.
902 The following options are available when @value{AS} is configured for
908 Enable or disable the JSRI to BSR transformation. By default this is enabled.
909 The command line option @samp{-nojsri2bsr} can be used to disable it.
913 Enable or disable the silicon filter behaviour. By default this is disabled.
914 The default can be overridden by the @samp{-sifilter} command line option.
917 Alter jump instructions for long displacements.
919 @item -mcpu=[210|340]
920 Select the cpu type on the target hardware. This controls which instructions
924 Assemble for a big endian target.
927 Assemble for a little endian target.
933 See the info pages for documentation of the MMIX-specific options.
939 * Manual:: Structure of this Manual
940 * GNU Assembler:: The GNU Assembler
941 * Object Formats:: Object File Formats
942 * Command Line:: Command Line
943 * Input Files:: Input Files
944 * Object:: Output (Object) File
945 * Errors:: Error and Warning Messages
949 @section Structure of this Manual
951 @cindex manual, structure and purpose
952 This manual is intended to describe what you need to know to use
953 @sc{gnu} @command{@value{AS}}. We cover the syntax expected in source files, including
954 notation for symbols, constants, and expressions; the directives that
955 @command{@value{AS}} understands; and of course how to invoke @command{@value{AS}}.
958 We also cover special features in the @value{TARGET}
959 configuration of @command{@value{AS}}, including assembler directives.
962 This manual also describes some of the machine-dependent features of
963 various flavors of the assembler.
966 @cindex machine instructions (not covered)
967 On the other hand, this manual is @emph{not} intended as an introduction
968 to programming in assembly language---let alone programming in general!
969 In a similar vein, we make no attempt to introduce the machine
970 architecture; we do @emph{not} describe the instruction set, standard
971 mnemonics, registers or addressing modes that are standard to a
972 particular architecture.
974 You may want to consult the manufacturer's
975 machine architecture manual for this information.
979 For information on the H8/300 machine instruction set, see @cite{H8/300
980 Series Programming Manual} (Hitachi ADE--602--025). For the H8/300H,
981 see @cite{H8/300H Series Programming Manual} (Hitachi).
984 For information on the H8/500 machine instruction set, see @cite{H8/500
985 Series Programming Manual} (Hitachi M21T001).
988 For information on the Hitachi SH machine instruction set, see
989 @cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.).
992 For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual}
996 @c I think this is premature---doc@cygnus.com, 17jan1991
998 Throughout this manual, we assume that you are running @dfn{GNU},
999 the portable operating system from the @dfn{Free Software
1000 Foundation, Inc.}. This restricts our attention to certain kinds of
1001 computer (in particular, the kinds of computers that @sc{gnu} can run on);
1002 once this assumption is granted examples and definitions need less
1005 @command{@value{AS}} is part of a team of programs that turn a high-level
1006 human-readable series of instructions into a low-level
1007 computer-readable series of instructions. Different versions of
1008 @command{@value{AS}} are used for different kinds of computer.
1011 @c There used to be a section "Terminology" here, which defined
1012 @c "contents", "byte", "word", and "long". Defining "word" to any
1013 @c particular size is confusing when the .word directive may generate 16
1014 @c bits on one machine and 32 bits on another; in general, for the user
1015 @c version of this manual, none of these terms seem essential to define.
1016 @c They were used very little even in the former draft of the manual;
1017 @c this draft makes an effort to avoid them (except in names of
1021 @section The GNU Assembler
1023 @c man begin DESCRIPTION
1025 @sc{gnu} @command{as} is really a family of assemblers.
1027 This manual describes @command{@value{AS}}, a member of that family which is
1028 configured for the @value{TARGET} architectures.
1030 If you use (or have used) the @sc{gnu} assembler on one architecture, you
1031 should find a fairly similar environment when you use it on another
1032 architecture. Each version has much in common with the others,
1033 including object file formats, most assembler directives (often called
1034 @dfn{pseudo-ops}) and assembler syntax.@refill
1036 @cindex purpose of @sc{gnu} assembler
1037 @command{@value{AS}} is primarily intended to assemble the output of the
1038 @sc{gnu} C compiler @code{@value{GCC}} for use by the linker
1039 @code{@value{LD}}. Nevertheless, we've tried to make @command{@value{AS}}
1040 assemble correctly everything that other assemblers for the same
1041 machine would assemble.
1043 Any exceptions are documented explicitly (@pxref{Machine Dependencies}).
1046 @c This remark should appear in generic version of manual; assumption
1047 @c here is that generic version sets M680x0.
1048 This doesn't mean @command{@value{AS}} always uses the same syntax as another
1049 assembler for the same architecture; for example, we know of several
1050 incompatible versions of 680x0 assembly language syntax.
1055 Unlike older assemblers, @command{@value{AS}} is designed to assemble a source
1056 program in one pass of the source file. This has a subtle impact on the
1057 @kbd{.org} directive (@pxref{Org,,@code{.org}}).
1059 @node Object Formats
1060 @section Object File Formats
1062 @cindex object file format
1063 The @sc{gnu} assembler can be configured to produce several alternative
1064 object file formats. For the most part, this does not affect how you
1065 write assembly language programs; but directives for debugging symbols
1066 are typically different in different file formats. @xref{Symbol
1067 Attributes,,Symbol Attributes}.
1070 On the @value{TARGET}, @command{@value{AS}} is configured to produce
1071 @value{OBJ-NAME} format object files.
1073 @c The following should exhaust all configs that set MULTI-OBJ, ideally
1075 On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
1076 @code{a.out} or COFF format object files.
1079 On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
1080 @code{b.out} or COFF format object files.
1083 On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
1084 SOM or ELF format object files.
1089 @section Command Line
1091 @cindex command line conventions
1093 After the program name @command{@value{AS}}, the command line may contain
1094 options and file names. Options may appear in any order, and may be
1095 before, after, or between file names. The order of file names is
1098 @cindex standard input, as input file
1100 @file{--} (two hyphens) by itself names the standard input file
1101 explicitly, as one of the files for @command{@value{AS}} to assemble.
1103 @cindex options, command line
1104 Except for @samp{--} any command line argument that begins with a
1105 hyphen (@samp{-}) is an option. Each option changes the behavior of
1106 @command{@value{AS}}. No option changes the way another option works. An
1107 option is a @samp{-} followed by one or more letters; the case of
1108 the letter is important. All options are optional.
1110 Some options expect exactly one file name to follow them. The file
1111 name may either immediately follow the option's letter (compatible
1112 with older assemblers) or it may be the next command argument (@sc{gnu}
1113 standard). These two command lines are equivalent:
1116 @value{AS} -o my-object-file.o mumble.s
1117 @value{AS} -omy-object-file.o mumble.s
1121 @section Input Files
1124 @cindex source program
1125 @cindex files, input
1126 We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
1127 describe the program input to one run of @command{@value{AS}}. The program may
1128 be in one or more files; how the source is partitioned into files
1129 doesn't change the meaning of the source.
1131 @c I added "con" prefix to "catenation" just to prove I can overcome my
1132 @c APL training... doc@cygnus.com
1133 The source program is a concatenation of the text in all the files, in the
1136 @c man begin DESCRIPTION
1137 Each time you run @command{@value{AS}} it assembles exactly one source
1138 program. The source program is made up of one or more files.
1139 (The standard input is also a file.)
1141 You give @command{@value{AS}} a command line that has zero or more input file
1142 names. The input files are read (from left file name to right). A
1143 command line argument (in any position) that has no special meaning
1144 is taken to be an input file name.
1146 If you give @command{@value{AS}} no file names it attempts to read one input file
1147 from the @command{@value{AS}} standard input, which is normally your terminal. You
1148 may have to type @key{ctl-D} to tell @command{@value{AS}} there is no more program
1151 Use @samp{--} if you need to explicitly name the standard input file
1152 in your command line.
1154 If the source is empty, @command{@value{AS}} produces a small, empty object
1159 @subheading Filenames and Line-numbers
1161 @cindex input file linenumbers
1162 @cindex line numbers, in input files
1163 There are two ways of locating a line in the input file (or files) and
1164 either may be used in reporting error messages. One way refers to a line
1165 number in a physical file; the other refers to a line number in a
1166 ``logical'' file. @xref{Errors, ,Error and Warning Messages}.
1168 @dfn{Physical files} are those files named in the command line given
1169 to @command{@value{AS}}.
1171 @dfn{Logical files} are simply names declared explicitly by assembler
1172 directives; they bear no relation to physical files. Logical file names help
1173 error messages reflect the original source file, when @command{@value{AS}} source
1174 is itself synthesized from other files. @command{@value{AS}} understands the
1175 @samp{#} directives emitted by the @code{@value{GCC}} preprocessor. See also
1176 @ref{File,,@code{.file}}.
1179 @section Output (Object) File
1185 Every time you run @command{@value{AS}} it produces an output file, which is
1186 your assembly language program translated into numbers. This file
1187 is the object file. Its default name is
1195 @code{b.out} when @command{@value{AS}} is configured for the Intel 80960.
1197 You can give it another name by using the @option{-o} option. Conventionally,
1198 object file names end with @file{.o}. The default name is used for historical
1199 reasons: older assemblers were capable of assembling self-contained programs
1200 directly into a runnable program. (For some formats, this isn't currently
1201 possible, but it can be done for the @code{a.out} format.)
1205 The object file is meant for input to the linker @code{@value{LD}}. It contains
1206 assembled program code, information to help @code{@value{LD}} integrate
1207 the assembled program into a runnable file, and (optionally) symbolic
1208 information for the debugger.
1210 @c link above to some info file(s) like the description of a.out.
1211 @c don't forget to describe @sc{gnu} info as well as Unix lossage.
1214 @section Error and Warning Messages
1216 @c man begin DESCRIPTION
1218 @cindex error messages
1219 @cindex warning messages
1220 @cindex messages from assembler
1221 @command{@value{AS}} may write warnings and error messages to the standard error
1222 file (usually your terminal). This should not happen when a compiler
1223 runs @command{@value{AS}} automatically. Warnings report an assumption made so
1224 that @command{@value{AS}} could keep assembling a flawed program; errors report a
1225 grave problem that stops the assembly.
1229 @cindex format of warning messages
1230 Warning messages have the format
1233 file_name:@b{NNN}:Warning Message Text
1237 @cindex line numbers, in warnings/errors
1238 (where @b{NNN} is a line number). If a logical file name has been given
1239 (@pxref{File,,@code{.file}}) it is used for the filename, otherwise the name of
1240 the current input file is used. If a logical line number was given
1242 (@pxref{Line,,@code{.line}})
1246 (@pxref{Line,,@code{.line}})
1249 (@pxref{Ln,,@code{.ln}})
1252 then it is used to calculate the number printed,
1253 otherwise the actual line in the current source file is printed. The
1254 message text is intended to be self explanatory (in the grand Unix
1257 @cindex format of error messages
1258 Error messages have the format
1260 file_name:@b{NNN}:FATAL:Error Message Text
1262 The file name and line number are derived as for warning
1263 messages. The actual message text may be rather less explanatory
1264 because many of them aren't supposed to happen.
1267 @chapter Command-Line Options
1269 @cindex options, all versions of assembler
1270 This chapter describes command-line options available in @emph{all}
1271 versions of the @sc{gnu} assembler; @pxref{Machine Dependencies}, for options specific
1273 to the @value{TARGET}.
1276 to particular machine architectures.
1279 @c man begin DESCRIPTION
1281 If you are invoking @command{@value{AS}} via the @sc{gnu} C compiler (version 2),
1282 you can use the @samp{-Wa} option to pass arguments through to the assembler.
1283 The assembler arguments must be separated from each other (and the @samp{-Wa})
1284 by commas. For example:
1287 gcc -c -g -O -Wa,-alh,-L file.c
1291 This passes two options to the assembler: @samp{-alh} (emit a listing to
1292 standard output with with high-level and assembly source) and @samp{-L} (retain
1293 local symbols in the symbol table).
1295 Usually you do not need to use this @samp{-Wa} mechanism, since many compiler
1296 command-line options are automatically passed to the assembler by the compiler.
1297 (You can call the @sc{gnu} compiler driver with the @samp{-v} option to see
1298 precisely what options it passes to each compilation pass, including the
1304 * a:: -a[cdhlns] enable listings
1305 * D:: -D for compatibility
1306 * f:: -f to work faster
1307 * I:: -I for .include search path
1308 @ifclear DIFF-TBL-KLUGE
1309 * K:: -K for compatibility
1311 @ifset DIFF-TBL-KLUGE
1312 * K:: -K for difference tables
1315 * L:: -L to retain local labels
1316 * listing:: --listing-XXX to configure listing output
1317 * M:: -M or --mri to assemble in MRI compatibility mode
1318 * MD:: --MD for dependency tracking
1319 * o:: -o to name the object file
1320 * R:: -R to join data and text sections
1321 * statistics:: --statistics to see statistics about assembly
1322 * traditional-format:: --traditional-format for compatible output
1323 * v:: -v to announce version
1324 * W:: -W, --no-warn, --warn, --fatal-warnings to control warnings
1325 * Z:: -Z to make object file even after errors
1329 @section Enable Listings: @option{-a[cdhlns]}
1338 @cindex listings, enabling
1339 @cindex assembly listings, enabling
1341 These options enable listing output from the assembler. By itself,
1342 @samp{-a} requests high-level, assembly, and symbols listing.
1343 You can use other letters to select specific options for the list:
1344 @samp{-ah} requests a high-level language listing,
1345 @samp{-al} requests an output-program assembly listing, and
1346 @samp{-as} requests a symbol table listing.
1347 High-level listings require that a compiler debugging option like
1348 @samp{-g} be used, and that assembly listings (@samp{-al}) be requested
1351 Use the @samp{-ac} option to omit false conditionals from a listing. Any lines
1352 which are not assembled because of a false @code{.if} (or @code{.ifdef}, or any
1353 other conditional), or a true @code{.if} followed by an @code{.else}, will be
1354 omitted from the listing.
1356 Use the @samp{-ad} option to omit debugging directives from the
1359 Once you have specified one of these options, you can further control
1360 listing output and its appearance using the directives @code{.list},
1361 @code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
1363 The @samp{-an} option turns off all forms processing.
1364 If you do not request listing output with one of the @samp{-a} options, the
1365 listing-control directives have no effect.
1367 The letters after @samp{-a} may be combined into one option,
1368 @emph{e.g.}, @samp{-aln}.
1370 Note if the assembler source is coming from the standard input (eg because it
1371 is being created by @code{@value{GCC}} and the @samp{-pipe} command line switch
1372 is being used) then the listing will not contain any comments or preprocessor
1373 directives. This is because the listing code buffers input source lines from
1374 stdin only after they have been preprocessed by the assembler. This reduces
1375 memory usage and makes the code more efficient.
1378 @section @option{-D}
1381 This option has no effect whatsoever, but it is accepted to make it more
1382 likely that scripts written for other assemblers also work with
1383 @command{@value{AS}}.
1386 @section Work Faster: @option{-f}
1389 @cindex trusted compiler
1390 @cindex faster processing (@option{-f})
1391 @samp{-f} should only be used when assembling programs written by a
1392 (trusted) compiler. @samp{-f} stops the assembler from doing whitespace
1393 and comment preprocessing on
1394 the input file(s) before assembling them. @xref{Preprocessing,
1398 @emph{Warning:} if you use @samp{-f} when the files actually need to be
1399 preprocessed (if they contain comments, for example), @command{@value{AS}} does
1404 @section @code{.include} search path: @option{-I} @var{path}
1406 @kindex -I @var{path}
1407 @cindex paths for @code{.include}
1408 @cindex search path for @code{.include}
1409 @cindex @code{include} directive search path
1410 Use this option to add a @var{path} to the list of directories
1411 @command{@value{AS}} searches for files specified in @code{.include}
1412 directives (@pxref{Include,,@code{.include}}). You may use @option{-I} as
1413 many times as necessary to include a variety of paths. The current
1414 working directory is always searched first; after that, @command{@value{AS}}
1415 searches any @samp{-I} directories in the same order as they were
1416 specified (left to right) on the command line.
1419 @section Difference Tables: @option{-K}
1422 @ifclear DIFF-TBL-KLUGE
1423 On the @value{TARGET} family, this option is allowed, but has no effect. It is
1424 permitted for compatibility with the @sc{gnu} assembler on other platforms,
1425 where it can be used to warn when the assembler alters the machine code
1426 generated for @samp{.word} directives in difference tables. The @value{TARGET}
1427 family does not have the addressing limitations that sometimes lead to this
1428 alteration on other platforms.
1431 @ifset DIFF-TBL-KLUGE
1432 @cindex difference tables, warning
1433 @cindex warning for altered difference tables
1434 @command{@value{AS}} sometimes alters the code emitted for directives of the form
1435 @samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}.
1436 You can use the @samp{-K} option if you want a warning issued when this
1441 @section Include Local Labels: @option{-L}
1444 @cindex local labels, retaining in output
1445 Labels beginning with @samp{L} (upper case only) are called @dfn{local
1446 labels}. @xref{Symbol Names}. Normally you do not see such labels when
1447 debugging, because they are intended for the use of programs (like
1448 compilers) that compose assembler programs, not for your notice.
1449 Normally both @command{@value{AS}} and @code{@value{LD}} discard such labels, so you do not
1450 normally debug with them.
1452 This option tells @command{@value{AS}} to retain those @samp{L@dots{}} symbols
1453 in the object file. Usually if you do this you also tell the linker
1454 @code{@value{LD}} to preserve symbols whose names begin with @samp{L}.
1456 By default, a local label is any label beginning with @samp{L}, but each
1457 target is allowed to redefine the local label prefix.
1459 On the HPPA local labels begin with @samp{L$}.
1463 @section Configuring listing output: @option{--listing}
1465 The listing feature of the assembler can be enabled via the command line switch
1466 @samp{-a} (@pxref{a}). This feature combines the input source file(s) with a
1467 hex dump of the corresponding locations in the output object file, and displays
1468 them as a listing file. The format of this listing can be controlled by pseudo
1469 ops inside the assembler source (@pxref{List} @pxref{Title} @pxref{Sbttl}
1470 @pxref{Psize} @pxref{Eject}) and also by the following switches:
1473 @item --listing-lhs-width=@samp{number}
1474 @kindex --listing-lhs-width
1475 @cindex Width of first line disassembly output
1476 Sets the maximum width, in words, of the first line of the hex byte dump. This
1477 dump appears on the left hand side of the listing output.
1479 @item --listing-lhs-width2=@samp{number}
1480 @kindex --listing-lhs-width2
1481 @cindex Width of continuation lines of disassembly output
1482 Sets the maximum width, in words, of any further lines of the hex byte dump for
1483 a given inut source line. If this value is not specified, it defaults to being
1484 the same as the value specified for @samp{--listing-lhs-width}. If neither
1485 switch is used the default is to one.
1487 @item --listing-rhs-width=@samp{number}
1488 @kindex --listing-rhs-width
1489 @cindex Width of source line output
1490 Sets the maximum width, in characters, of the source line that is displayed
1491 alongside the hex dump. The default value for this parameter is 100. The
1492 source line is displayed on the right hand side of the listing output.
1494 @item --listing-cont-lines=@samp{number}
1495 @kindex --listing-cont-lines
1496 @cindex Maximum number of continuation lines
1497 Sets the maximum number of continuation lines of hex dump that will be
1498 displayed for a given single line of source input. The default value is 4.
1502 @section Assemble in MRI Compatibility Mode: @option{-M}
1505 @cindex MRI compatibility mode
1506 The @option{-M} or @option{--mri} option selects MRI compatibility mode. This
1507 changes the syntax and pseudo-op handling of @command{@value{AS}} to make it
1508 compatible with the @code{ASM68K} or the @code{ASM960} (depending upon the
1509 configured target) assembler from Microtec Research. The exact nature of the
1510 MRI syntax will not be documented here; see the MRI manuals for more
1511 information. Note in particular that the handling of macros and macro
1512 arguments is somewhat different. The purpose of this option is to permit
1513 assembling existing MRI assembler code using @command{@value{AS}}.
1515 The MRI compatibility is not complete. Certain operations of the MRI assembler
1516 depend upon its object file format, and can not be supported using other object
1517 file formats. Supporting these would require enhancing each object file format
1518 individually. These are:
1521 @item global symbols in common section
1523 The m68k MRI assembler supports common sections which are merged by the linker.
1524 Other object file formats do not support this. @command{@value{AS}} handles
1525 common sections by treating them as a single common symbol. It permits local
1526 symbols to be defined within a common section, but it can not support global
1527 symbols, since it has no way to describe them.
1529 @item complex relocations
1531 The MRI assemblers support relocations against a negated section address, and
1532 relocations which combine the start addresses of two or more sections. These
1533 are not support by other object file formats.
1535 @item @code{END} pseudo-op specifying start address
1537 The MRI @code{END} pseudo-op permits the specification of a start address.
1538 This is not supported by other object file formats. The start address may
1539 instead be specified using the @option{-e} option to the linker, or in a linker
1542 @item @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops
1544 The MRI @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops assign a module
1545 name to the output file. This is not supported by other object file formats.
1547 @item @code{ORG} pseudo-op
1549 The m68k MRI @code{ORG} pseudo-op begins an absolute section at a given
1550 address. This differs from the usual @command{@value{AS}} @code{.org} pseudo-op,
1551 which changes the location within the current section. Absolute sections are
1552 not supported by other object file formats. The address of a section may be
1553 assigned within a linker script.
1556 There are some other features of the MRI assembler which are not supported by
1557 @command{@value{AS}}, typically either because they are difficult or because they
1558 seem of little consequence. Some of these may be supported in future releases.
1562 @item EBCDIC strings
1564 EBCDIC strings are not supported.
1566 @item packed binary coded decimal
1568 Packed binary coded decimal is not supported. This means that the @code{DC.P}
1569 and @code{DCB.P} pseudo-ops are not supported.
1571 @item @code{FEQU} pseudo-op
1573 The m68k @code{FEQU} pseudo-op is not supported.
1575 @item @code{NOOBJ} pseudo-op
1577 The m68k @code{NOOBJ} pseudo-op is not supported.
1579 @item @code{OPT} branch control options
1581 The m68k @code{OPT} branch control options---@code{B}, @code{BRS}, @code{BRB},
1582 @code{BRL}, and @code{BRW}---are ignored. @command{@value{AS}} automatically
1583 relaxes all branches, whether forward or backward, to an appropriate size, so
1584 these options serve no purpose.
1586 @item @code{OPT} list control options
1588 The following m68k @code{OPT} list control options are ignored: @code{C},
1589 @code{CEX}, @code{CL}, @code{CRE}, @code{E}, @code{G}, @code{I}, @code{M},
1590 @code{MEX}, @code{MC}, @code{MD}, @code{X}.
1592 @item other @code{OPT} options
1594 The following m68k @code{OPT} options are ignored: @code{NEST}, @code{O},
1595 @code{OLD}, @code{OP}, @code{P}, @code{PCO}, @code{PCR}, @code{PCS}, @code{R}.
1597 @item @code{OPT} @code{D} option is default
1599 The m68k @code{OPT} @code{D} option is the default, unlike the MRI assembler.
1600 @code{OPT NOD} may be used to turn it off.
1602 @item @code{XREF} pseudo-op.
1604 The m68k @code{XREF} pseudo-op is ignored.
1606 @item @code{.debug} pseudo-op
1608 The i960 @code{.debug} pseudo-op is not supported.
1610 @item @code{.extended} pseudo-op
1612 The i960 @code{.extended} pseudo-op is not supported.
1614 @item @code{.list} pseudo-op.
1616 The various options of the i960 @code{.list} pseudo-op are not supported.
1618 @item @code{.optimize} pseudo-op
1620 The i960 @code{.optimize} pseudo-op is not supported.
1622 @item @code{.output} pseudo-op
1624 The i960 @code{.output} pseudo-op is not supported.
1626 @item @code{.setreal} pseudo-op
1628 The i960 @code{.setreal} pseudo-op is not supported.
1633 @section Dependency tracking: @option{--MD}
1636 @cindex dependency tracking
1639 @command{@value{AS}} can generate a dependency file for the file it creates. This
1640 file consists of a single rule suitable for @code{make} describing the
1641 dependencies of the main source file.
1643 The rule is written to the file named in its argument.
1645 This feature is used in the automatic updating of makefiles.
1648 @section Name the Object File: @option{-o}
1651 @cindex naming object file
1652 @cindex object file name
1653 There is always one object file output when you run @command{@value{AS}}. By
1654 default it has the name
1657 @file{a.out} (or @file{b.out}, for Intel 960 targets only).
1671 You use this option (which takes exactly one filename) to give the
1672 object file a different name.
1674 Whatever the object file is called, @command{@value{AS}} overwrites any
1675 existing file of the same name.
1678 @section Join Data and Text Sections: @option{-R}
1681 @cindex data and text sections, joining
1682 @cindex text and data sections, joining
1683 @cindex joining text and data sections
1684 @cindex merging text and data sections
1685 @option{-R} tells @command{@value{AS}} to write the object file as if all
1686 data-section data lives in the text section. This is only done at
1687 the very last moment: your binary data are the same, but data
1688 section parts are relocated differently. The data section part of
1689 your object file is zero bytes long because all its bytes are
1690 appended to the text section. (@xref{Sections,,Sections and Relocation}.)
1692 When you specify @option{-R} it would be possible to generate shorter
1693 address displacements (because we do not have to cross between text and
1694 data section). We refrain from doing this simply for compatibility with
1695 older versions of @command{@value{AS}}. In future, @option{-R} may work this way.
1698 When @command{@value{AS}} is configured for COFF output,
1699 this option is only useful if you use sections named @samp{.text} and
1704 @option{-R} is not supported for any of the HPPA targets. Using
1705 @option{-R} generates a warning from @command{@value{AS}}.
1709 @section Display Assembly Statistics: @option{--statistics}
1711 @kindex --statistics
1712 @cindex statistics, about assembly
1713 @cindex time, total for assembly
1714 @cindex space used, maximum for assembly
1715 Use @samp{--statistics} to display two statistics about the resources used by
1716 @command{@value{AS}}: the maximum amount of space allocated during the assembly
1717 (in bytes), and the total execution time taken for the assembly (in @sc{cpu}
1720 @node traditional-format
1721 @section Compatible output: @option{--traditional-format}
1723 @kindex --traditional-format
1724 For some targets, the output of @command{@value{AS}} is different in some ways
1725 from the output of some existing assembler. This switch requests
1726 @command{@value{AS}} to use the traditional format instead.
1728 For example, it disables the exception frame optimizations which
1729 @command{@value{AS}} normally does by default on @code{@value{GCC}} output.
1732 @section Announce Version: @option{-v}
1736 @cindex assembler version
1737 @cindex version of assembler
1738 You can find out what version of as is running by including the
1739 option @samp{-v} (which you can also spell as @samp{-version}) on the
1743 @section Control Warnings: @option{-W}, @option{--warn}, @option{--no-warn}, @option{--fatal-warnings}
1745 @command{@value{AS}} should never give a warning or error message when
1746 assembling compiler output. But programs written by people often
1747 cause @command{@value{AS}} to give a warning that a particular assumption was
1748 made. All such warnings are directed to the standard error file.
1751 @kindex @samp{--no-warn}
1752 @cindex suppressing warnings
1753 @cindex warnings, suppressing
1754 If you use the @option{-W} and @option{--no-warn} options, no warnings are issued.
1755 This only affects the warning messages: it does not change any particular of
1756 how @command{@value{AS}} assembles your file. Errors, which stop the assembly,
1759 @kindex @samp{--fatal-warnings}
1760 @cindex errors, caused by warnings
1761 @cindex warnings, causing error
1762 If you use the @option{--fatal-warnings} option, @command{@value{AS}} considers
1763 files that generate warnings to be in error.
1765 @kindex @samp{--warn}
1766 @cindex warnings, switching on
1767 You can switch these options off again by specifying @option{--warn}, which
1768 causes warnings to be output as usual.
1771 @section Generate Object File in Spite of Errors: @option{-Z}
1772 @cindex object file, after errors
1773 @cindex errors, continuing after
1774 After an error message, @command{@value{AS}} normally produces no output. If for
1775 some reason you are interested in object file output even after
1776 @command{@value{AS}} gives an error message on your program, use the @samp{-Z}
1777 option. If there are any errors, @command{@value{AS}} continues anyways, and
1778 writes an object file after a final warning message of the form @samp{@var{n}
1779 errors, @var{m} warnings, generating bad object file.}
1784 @cindex machine-independent syntax
1785 @cindex syntax, machine-independent
1786 This chapter describes the machine-independent syntax allowed in a
1787 source file. @command{@value{AS}} syntax is similar to what many other
1788 assemblers use; it is inspired by the BSD 4.2
1793 assembler, except that @command{@value{AS}} does not assemble Vax bit-fields.
1797 * Preprocessing:: Preprocessing
1798 * Whitespace:: Whitespace
1799 * Comments:: Comments
1800 * Symbol Intro:: Symbols
1801 * Statements:: Statements
1802 * Constants:: Constants
1806 @section Preprocessing
1808 @cindex preprocessing
1809 The @command{@value{AS}} internal preprocessor:
1811 @cindex whitespace, removed by preprocessor
1813 adjusts and removes extra whitespace. It leaves one space or tab before
1814 the keywords on a line, and turns any other whitespace on the line into
1817 @cindex comments, removed by preprocessor
1819 removes all comments, replacing them with a single space, or an
1820 appropriate number of newlines.
1822 @cindex constants, converted by preprocessor
1824 converts character constants into the appropriate numeric values.
1827 It does not do macro processing, include file handling, or
1828 anything else you may get from your C compiler's preprocessor. You can
1829 do include file processing with the @code{.include} directive
1830 (@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver
1831 to get other ``CPP'' style preprocessing, by giving the input file a
1832 @samp{.S} suffix. @xref{Overall Options,, Options Controlling the Kind of
1833 Output, gcc.info, Using GNU CC}.
1835 Excess whitespace, comments, and character constants
1836 cannot be used in the portions of the input text that are not
1839 @cindex turning preprocessing on and off
1840 @cindex preprocessing, turning on and off
1843 If the first line of an input file is @code{#NO_APP} or if you use the
1844 @samp{-f} option, whitespace and comments are not removed from the input file.
1845 Within an input file, you can ask for whitespace and comment removal in
1846 specific portions of the by putting a line that says @code{#APP} before the
1847 text that may contain whitespace or comments, and putting a line that says
1848 @code{#NO_APP} after this text. This feature is mainly intend to support
1849 @code{asm} statements in compilers whose output is otherwise free of comments
1856 @dfn{Whitespace} is one or more blanks or tabs, in any order.
1857 Whitespace is used to separate symbols, and to make programs neater for
1858 people to read. Unless within character constants
1859 (@pxref{Characters,,Character Constants}), any whitespace means the same
1860 as exactly one space.
1866 There are two ways of rendering comments to @command{@value{AS}}. In both
1867 cases the comment is equivalent to one space.
1869 Anything from @samp{/*} through the next @samp{*/} is a comment.
1870 This means you may not nest these comments.
1874 The only way to include a newline ('\n') in a comment
1875 is to use this sort of comment.
1878 /* This sort of comment does not nest. */
1881 @cindex line comment character
1882 Anything from the @dfn{line comment} character to the next newline
1883 is considered a comment and is ignored. The line comment character is
1885 @samp{;} for the AMD 29K family;
1888 @samp{;} on the ARC;
1891 @samp{@@} on the ARM;
1894 @samp{;} for the H8/300 family;
1897 @samp{!} for the H8/500 family;
1900 @samp{;} for the HPPA;
1903 @samp{#} on the i386 and x86-64;
1906 @samp{#} on the i960;
1909 @samp{;} for the PDP-11;
1912 @samp{;} for picoJava;
1915 @samp{;} for Motorola PowerPC;
1918 @samp{!} for the Hitachi SH;
1921 @samp{!} on the SPARC;
1924 @samp{#} on the m32r;
1927 @samp{|} on the 680x0;
1930 @samp{#} on the 68HC11 and 68HC12;
1933 @samp{;} on the M880x0;
1936 @samp{#} on the Vax;
1939 @samp{!} for the Z8000;
1942 @samp{#} on the V850;
1944 see @ref{Machine Dependencies}. @refill
1945 @c FIXME What about i860?
1948 On some machines there are two different line comment characters. One
1949 character only begins a comment if it is the first non-whitespace character on
1950 a line, while the other always begins a comment.
1954 The V850 assembler also supports a double dash as starting a comment that
1955 extends to the end of the line.
1961 @cindex lines starting with @code{#}
1962 @cindex logical line numbers
1963 To be compatible with past assemblers, lines that begin with @samp{#} have a
1964 special interpretation. Following the @samp{#} should be an absolute
1965 expression (@pxref{Expressions}): the logical line number of the @emph{next}
1966 line. Then a string (@pxref{Strings,, Strings}) is allowed: if present it is a
1967 new logical file name. The rest of the line, if any, should be whitespace.
1969 If the first non-whitespace characters on the line are not numeric,
1970 the line is ignored. (Just like a comment.)
1973 # This is an ordinary comment.
1974 # 42-6 "new_file_name" # New logical file name
1975 # This is logical line # 36.
1977 This feature is deprecated, and may disappear from future versions
1978 of @command{@value{AS}}.
1983 @cindex characters used in symbols
1984 @ifclear SPECIAL-SYMS
1985 A @dfn{symbol} is one or more characters chosen from the set of all
1986 letters (both upper and lower case), digits and the three characters
1992 A @dfn{symbol} is one or more characters chosen from the set of all
1993 letters (both upper and lower case), digits and the three characters
1994 @samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in
2000 On most machines, you can also use @code{$} in symbol names; exceptions
2001 are noted in @ref{Machine Dependencies}.
2003 No symbol may begin with a digit. Case is significant.
2004 There is no length limit: all characters are significant. Symbols are
2005 delimited by characters not in that set, or by the beginning of a file
2006 (since the source program must end with a newline, the end of a file is
2007 not a possible symbol delimiter). @xref{Symbols}.
2008 @cindex length of symbols
2013 @cindex statements, structure of
2014 @cindex line separator character
2015 @cindex statement separator character
2017 @ifclear abnormal-separator
2018 A @dfn{statement} ends at a newline character (@samp{\n}) or at a
2019 semicolon (@samp{;}). The newline or semicolon is considered part of
2020 the preceding statement. Newlines and semicolons within character
2021 constants are an exception: they do not end statements.
2023 @ifset abnormal-separator
2025 A @dfn{statement} ends at a newline character (@samp{\n}) or an ``at''
2026 sign (@samp{@@}). The newline or at sign is considered part of the
2027 preceding statement. Newlines and at signs within character constants
2028 are an exception: they do not end statements.
2031 A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation
2032 point (@samp{!}). The newline or exclamation point is considered part of the
2033 preceding statement. Newlines and exclamation points within character
2034 constants are an exception: they do not end statements.
2037 A @dfn{statement} ends at a newline character (@samp{\n}); or (for the
2038 H8/300) a dollar sign (@samp{$}); or (for the
2041 (@samp{;}). The newline or separator character is considered part of
2042 the preceding statement. Newlines and separators within character
2043 constants are an exception: they do not end statements.
2048 A @dfn{statement} ends at a newline character (@samp{\n}) or line
2049 separator character. (The line separator is usually @samp{;}, unless
2050 this conflicts with the comment character; @pxref{Machine Dependencies}.) The
2051 newline or separator character is considered part of the preceding
2052 statement. Newlines and separators within character constants are an
2053 exception: they do not end statements.
2056 @cindex newline, required at file end
2057 @cindex EOF, newline must precede
2058 It is an error to end any statement with end-of-file: the last
2059 character of any input file should be a newline.@refill
2061 An empty statement is allowed, and may include whitespace. It is ignored.
2063 @cindex instructions and directives
2064 @cindex directives and instructions
2065 @c "key symbol" is not used elsewhere in the document; seems pedantic to
2066 @c @defn{} it in that case, as was done previously... doc@cygnus.com,
2068 A statement begins with zero or more labels, optionally followed by a
2069 key symbol which determines what kind of statement it is. The key
2070 symbol determines the syntax of the rest of the statement. If the
2071 symbol begins with a dot @samp{.} then the statement is an assembler
2072 directive: typically valid for any computer. If the symbol begins with
2073 a letter the statement is an assembly language @dfn{instruction}: it
2074 assembles into a machine language instruction.
2076 Different versions of @command{@value{AS}} for different computers
2077 recognize different instructions. In fact, the same symbol may
2078 represent a different instruction in a different computer's assembly
2082 @cindex @code{:} (label)
2083 @cindex label (@code{:})
2084 A label is a symbol immediately followed by a colon (@code{:}).
2085 Whitespace before a label or after a colon is permitted, but you may not
2086 have whitespace between a label's symbol and its colon. @xref{Labels}.
2089 For HPPA targets, labels need not be immediately followed by a colon, but
2090 the definition of a label must begin in column zero. This also implies that
2091 only one label may be defined on each line.
2095 label: .directive followed by something
2096 another_label: # This is an empty statement.
2097 instruction operand_1, operand_2, @dots{}
2104 A constant is a number, written so that its value is known by
2105 inspection, without knowing any context. Like this:
2108 .byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
2109 .ascii "Ring the bell\7" # A string constant.
2110 .octa 0x123456789abcdef0123456789ABCDEF0 # A bignum.
2111 .float 0f-314159265358979323846264338327\
2112 95028841971.693993751E-40 # - pi, a flonum.
2117 * Characters:: Character Constants
2118 * Numbers:: Number Constants
2122 @subsection Character Constants
2124 @cindex character constants
2125 @cindex constants, character
2126 There are two kinds of character constants. A @dfn{character} stands
2127 for one character in one byte and its value may be used in
2128 numeric expressions. String constants (properly called string
2129 @emph{literals}) are potentially many bytes and their values may not be
2130 used in arithmetic expressions.
2134 * Chars:: Characters
2138 @subsubsection Strings
2140 @cindex string constants
2141 @cindex constants, string
2142 A @dfn{string} is written between double-quotes. It may contain
2143 double-quotes or null characters. The way to get special characters
2144 into a string is to @dfn{escape} these characters: precede them with
2145 a backslash @samp{\} character. For example @samp{\\} represents
2146 one backslash: the first @code{\} is an escape which tells
2147 @command{@value{AS}} to interpret the second character literally as a backslash
2148 (which prevents @command{@value{AS}} from recognizing the second @code{\} as an
2149 escape character). The complete list of escapes follows.
2151 @cindex escape codes, character
2152 @cindex character escape codes
2155 @c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
2157 @cindex @code{\b} (backspace character)
2158 @cindex backspace (@code{\b})
2160 Mnemonic for backspace; for ASCII this is octal code 010.
2163 @c Mnemonic for EOText; for ASCII this is octal code 004.
2165 @cindex @code{\f} (formfeed character)
2166 @cindex formfeed (@code{\f})
2168 Mnemonic for FormFeed; for ASCII this is octal code 014.
2170 @cindex @code{\n} (newline character)
2171 @cindex newline (@code{\n})
2173 Mnemonic for newline; for ASCII this is octal code 012.
2176 @c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
2178 @cindex @code{\r} (carriage return character)
2179 @cindex carriage return (@code{\r})
2181 Mnemonic for carriage-Return; for ASCII this is octal code 015.
2184 @c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
2185 @c other assemblers.
2187 @cindex @code{\t} (tab)
2188 @cindex tab (@code{\t})
2190 Mnemonic for horizontal Tab; for ASCII this is octal code 011.
2193 @c Mnemonic for Vertical tab; for ASCII this is octal code 013.
2194 @c @item \x @var{digit} @var{digit} @var{digit}
2195 @c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
2197 @cindex @code{\@var{ddd}} (octal character code)
2198 @cindex octal character code (@code{\@var{ddd}})
2199 @item \ @var{digit} @var{digit} @var{digit}
2200 An octal character code. The numeric code is 3 octal digits.
2201 For compatibility with other Unix systems, 8 and 9 are accepted as digits:
2202 for example, @code{\008} has the value 010, and @code{\009} the value 011.
2204 @cindex @code{\@var{xd...}} (hex character code)
2205 @cindex hex character code (@code{\@var{xd...}})
2206 @item \@code{x} @var{hex-digits...}
2207 A hex character code. All trailing hex digits are combined. Either upper or
2208 lower case @code{x} works.
2210 @cindex @code{\\} (@samp{\} character)
2211 @cindex backslash (@code{\\})
2213 Represents one @samp{\} character.
2216 @c Represents one @samp{'} (accent acute) character.
2217 @c This is needed in single character literals
2218 @c (@xref{Characters,,Character Constants}.) to represent
2221 @cindex @code{\"} (doublequote character)
2222 @cindex doublequote (@code{\"})
2224 Represents one @samp{"} character. Needed in strings to represent
2225 this character, because an unescaped @samp{"} would end the string.
2227 @item \ @var{anything-else}
2228 Any other character when escaped by @kbd{\} gives a warning, but
2229 assembles as if the @samp{\} was not present. The idea is that if
2230 you used an escape sequence you clearly didn't want the literal
2231 interpretation of the following character. However @command{@value{AS}} has no
2232 other interpretation, so @command{@value{AS}} knows it is giving you the wrong
2233 code and warns you of the fact.
2236 Which characters are escapable, and what those escapes represent,
2237 varies widely among assemblers. The current set is what we think
2238 the BSD 4.2 assembler recognizes, and is a subset of what most C
2239 compilers recognize. If you are in doubt, do not use an escape
2243 @subsubsection Characters
2245 @cindex single character constant
2246 @cindex character, single
2247 @cindex constant, single character
2248 A single character may be written as a single quote immediately
2249 followed by that character. The same escapes apply to characters as
2250 to strings. So if you want to write the character backslash, you
2251 must write @kbd{'\\} where the first @code{\} escapes the second
2252 @code{\}. As you can see, the quote is an acute accent, not a
2253 grave accent. A newline
2255 @ifclear abnormal-separator
2256 (or semicolon @samp{;})
2258 @ifset abnormal-separator
2260 (or at sign @samp{@@})
2263 (or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the
2269 immediately following an acute accent is taken as a literal character
2270 and does not count as the end of a statement. The value of a character
2271 constant in a numeric expression is the machine's byte-wide code for
2272 that character. @command{@value{AS}} assumes your character code is ASCII:
2273 @kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill
2276 @subsection Number Constants
2278 @cindex constants, number
2279 @cindex number constants
2280 @command{@value{AS}} distinguishes three kinds of numbers according to how they
2281 are stored in the target machine. @emph{Integers} are numbers that
2282 would fit into an @code{int} in the C language. @emph{Bignums} are
2283 integers, but they are stored in more than 32 bits. @emph{Flonums}
2284 are floating point numbers, described below.
2287 * Integers:: Integers
2292 * Bit Fields:: Bit Fields
2298 @subsubsection Integers
2300 @cindex constants, integer
2302 @cindex binary integers
2303 @cindex integers, binary
2304 A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
2305 the binary digits @samp{01}.
2307 @cindex octal integers
2308 @cindex integers, octal
2309 An octal integer is @samp{0} followed by zero or more of the octal
2310 digits (@samp{01234567}).
2312 @cindex decimal integers
2313 @cindex integers, decimal
2314 A decimal integer starts with a non-zero digit followed by zero or
2315 more digits (@samp{0123456789}).
2317 @cindex hexadecimal integers
2318 @cindex integers, hexadecimal
2319 A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
2320 more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
2322 Integers have the usual values. To denote a negative integer, use
2323 the prefix operator @samp{-} discussed under expressions
2324 (@pxref{Prefix Ops,,Prefix Operators}).
2327 @subsubsection Bignums
2330 @cindex constants, bignum
2331 A @dfn{bignum} has the same syntax and semantics as an integer
2332 except that the number (or its negative) takes more than 32 bits to
2333 represent in binary. The distinction is made because in some places
2334 integers are permitted while bignums are not.
2337 @subsubsection Flonums
2339 @cindex floating point numbers
2340 @cindex constants, floating point
2342 @cindex precision, floating point
2343 A @dfn{flonum} represents a floating point number. The translation is
2344 indirect: a decimal floating point number from the text is converted by
2345 @command{@value{AS}} to a generic binary floating point number of more than
2346 sufficient precision. This generic floating point number is converted
2347 to a particular computer's floating point format (or formats) by a
2348 portion of @command{@value{AS}} specialized to that computer.
2350 A flonum is written by writing (in order)
2355 (@samp{0} is optional on the HPPA.)
2359 A letter, to tell @command{@value{AS}} the rest of the number is a flonum.
2361 @kbd{e} is recommended. Case is not important.
2363 @c FIXME: verify if flonum syntax really this vague for most cases
2364 (Any otherwise illegal letter works here, but that might be changed. Vax BSD
2365 4.2 assembler seems to allow any of @samp{defghDEFGH}.)
2368 On the H8/300, H8/500,
2370 and AMD 29K architectures, the letter must be
2371 one of the letters @samp{DFPRSX} (in upper or lower case).
2373 On the ARC, the letter must be one of the letters @samp{DFRS}
2374 (in upper or lower case).
2376 On the Intel 960 architecture, the letter must be
2377 one of the letters @samp{DFT} (in upper or lower case).
2379 On the HPPA architecture, the letter must be @samp{E} (upper case only).
2383 One of the letters @samp{DFPRSX} (in upper or lower case).
2386 One of the letters @samp{DFRS} (in upper or lower case).
2389 One of the letters @samp{DFPRSX} (in upper or lower case).
2392 The letter @samp{E} (upper case only).
2395 One of the letters @samp{DFT} (in upper or lower case).
2400 An optional sign: either @samp{+} or @samp{-}.
2403 An optional @dfn{integer part}: zero or more decimal digits.
2406 An optional @dfn{fractional part}: @samp{.} followed by zero
2407 or more decimal digits.
2410 An optional exponent, consisting of:
2414 An @samp{E} or @samp{e}.
2415 @c I can't find a config where "EXP_CHARS" is other than 'eE', but in
2416 @c principle this can perfectly well be different on different targets.
2418 Optional sign: either @samp{+} or @samp{-}.
2420 One or more decimal digits.
2425 At least one of the integer part or the fractional part must be
2426 present. The floating point number has the usual base-10 value.
2428 @command{@value{AS}} does all processing using integers. Flonums are computed
2429 independently of any floating point hardware in the computer running
2430 @command{@value{AS}}.
2434 @c Bit fields are written as a general facility but are also controlled
2435 @c by a conditional-compilation flag---which is as of now (21mar91)
2436 @c turned on only by the i960 config of GAS.
2438 @subsubsection Bit Fields
2441 @cindex constants, bit field
2442 You can also define numeric constants as @dfn{bit fields}.
2443 specify two numbers separated by a colon---
2445 @var{mask}:@var{value}
2448 @command{@value{AS}} applies a bitwise @sc{and} between @var{mask} and
2451 The resulting number is then packed
2453 @c this conditional paren in case bit fields turned on elsewhere than 960
2454 (in host-dependent byte order)
2456 into a field whose width depends on which assembler directive has the
2457 bit-field as its argument. Overflow (a result from the bitwise and
2458 requiring more binary digits to represent) is not an error; instead,
2459 more constants are generated, of the specified width, beginning with the
2460 least significant digits.@refill
2462 The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long},
2463 @code{.short}, and @code{.word} accept bit-field arguments.
2468 @chapter Sections and Relocation
2473 * Secs Background:: Background
2474 * Ld Sections:: Linker Sections
2475 * As Sections:: Assembler Internal Sections
2476 * Sub-Sections:: Sub-Sections
2480 @node Secs Background
2483 Roughly, a section is a range of addresses, with no gaps; all data
2484 ``in'' those addresses is treated the same for some particular purpose.
2485 For example there may be a ``read only'' section.
2487 @cindex linker, and assembler
2488 @cindex assembler, and linker
2489 The linker @code{@value{LD}} reads many object files (partial programs) and
2490 combines their contents to form a runnable program. When @command{@value{AS}}
2491 emits an object file, the partial program is assumed to start at address 0.
2492 @code{@value{LD}} assigns the final addresses for the partial program, so that
2493 different partial programs do not overlap. This is actually an
2494 oversimplification, but it suffices to explain how @command{@value{AS}} uses
2497 @code{@value{LD}} moves blocks of bytes of your program to their run-time
2498 addresses. These blocks slide to their run-time addresses as rigid
2499 units; their length does not change and neither does the order of bytes
2500 within them. Such a rigid unit is called a @emph{section}. Assigning
2501 run-time addresses to sections is called @dfn{relocation}. It includes
2502 the task of adjusting mentions of object-file addresses so they refer to
2503 the proper run-time addresses.
2505 For the H8/300 and H8/500,
2506 and for the Hitachi SH,
2507 @command{@value{AS}} pads sections if needed to
2508 ensure they end on a word (sixteen bit) boundary.
2511 @cindex standard assembler sections
2512 An object file written by @command{@value{AS}} has at least three sections, any
2513 of which may be empty. These are named @dfn{text}, @dfn{data} and
2518 When it generates COFF output,
2520 @command{@value{AS}} can also generate whatever other named sections you specify
2521 using the @samp{.section} directive (@pxref{Section,,@code{.section}}).
2522 If you do not use any directives that place output in the @samp{.text}
2523 or @samp{.data} sections, these sections still exist, but are empty.
2528 When @command{@value{AS}} generates SOM or ELF output for the HPPA,
2530 @command{@value{AS}} can also generate whatever other named sections you
2531 specify using the @samp{.space} and @samp{.subspace} directives. See
2532 @cite{HP9000 Series 800 Assembly Language Reference Manual}
2533 (HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
2534 assembler directives.
2537 Additionally, @command{@value{AS}} uses different names for the standard
2538 text, data, and bss sections when generating SOM output. Program text
2539 is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
2540 BSS into @samp{$BSS$}.
2544 Within the object file, the text section starts at address @code{0}, the
2545 data section follows, and the bss section follows the data section.
2548 When generating either SOM or ELF output files on the HPPA, the text
2549 section starts at address @code{0}, the data section at address
2550 @code{0x4000000}, and the bss section follows the data section.
2553 To let @code{@value{LD}} know which data changes when the sections are
2554 relocated, and how to change that data, @command{@value{AS}} also writes to the
2555 object file details of the relocation needed. To perform relocation
2556 @code{@value{LD}} must know, each time an address in the object
2560 Where in the object file is the beginning of this reference to
2563 How long (in bytes) is this reference?
2565 Which section does the address refer to? What is the numeric value of
2567 (@var{address}) @minus{} (@var{start-address of section})?
2570 Is the reference to an address ``Program-Counter relative''?
2573 @cindex addresses, format of
2574 @cindex section-relative addressing
2575 In fact, every address @command{@value{AS}} ever uses is expressed as
2577 (@var{section}) + (@var{offset into section})
2580 Further, most expressions @command{@value{AS}} computes have this section-relative
2583 (For some object formats, such as SOM for the HPPA, some expressions are
2584 symbol-relative instead.)
2587 In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset
2588 @var{N} into section @var{secname}.''
2590 Apart from text, data and bss sections you need to know about the
2591 @dfn{absolute} section. When @code{@value{LD}} mixes partial programs,
2592 addresses in the absolute section remain unchanged. For example, address
2593 @code{@{absolute 0@}} is ``relocated'' to run-time address 0 by
2594 @code{@value{LD}}. Although the linker never arranges two partial programs'
2595 data sections with overlapping addresses after linking, @emph{by definition}
2596 their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one
2597 part of a program is always the same address when the program is running as
2598 address @code{@{absolute@ 239@}} in any other part of the program.
2600 The idea of sections is extended to the @dfn{undefined} section. Any
2601 address whose section is unknown at assembly time is by definition
2602 rendered @{undefined @var{U}@}---where @var{U} is filled in later.
2603 Since numbers are always defined, the only way to generate an undefined
2604 address is to mention an undefined symbol. A reference to a named
2605 common block would be such a symbol: its value is unknown at assembly
2606 time so it has section @emph{undefined}.
2608 By analogy the word @emph{section} is used to describe groups of sections in
2609 the linked program. @code{@value{LD}} puts all partial programs' text
2610 sections in contiguous addresses in the linked program. It is
2611 customary to refer to the @emph{text section} of a program, meaning all
2612 the addresses of all partial programs' text sections. Likewise for
2613 data and bss sections.
2615 Some sections are manipulated by @code{@value{LD}}; others are invented for
2616 use of @command{@value{AS}} and have no meaning except during assembly.
2619 @section Linker Sections
2620 @code{@value{LD}} deals with just four kinds of sections, summarized below.
2625 @cindex named sections
2626 @cindex sections, named
2627 @item named sections
2630 @cindex text section
2631 @cindex data section
2635 These sections hold your program. @command{@value{AS}} and @code{@value{LD}} treat them as
2636 separate but equal sections. Anything you can say of one section is
2639 When the program is running, however, it is
2640 customary for the text section to be unalterable. The
2641 text section is often shared among processes: it contains
2642 instructions, constants and the like. The data section of a running
2643 program is usually alterable: for example, C variables would be stored
2644 in the data section.
2649 This section contains zeroed bytes when your program begins running. It
2650 is used to hold uninitialized variables or common storage. The length of
2651 each partial program's bss section is important, but because it starts
2652 out containing zeroed bytes there is no need to store explicit zero
2653 bytes in the object file. The bss section was invented to eliminate
2654 those explicit zeros from object files.
2656 @cindex absolute section
2657 @item absolute section
2658 Address 0 of this section is always ``relocated'' to runtime address 0.
2659 This is useful if you want to refer to an address that @code{@value{LD}} must
2660 not change when relocating. In this sense we speak of absolute
2661 addresses being ``unrelocatable'': they do not change during relocation.
2663 @cindex undefined section
2664 @item undefined section
2665 This ``section'' is a catch-all for address references to objects not in
2666 the preceding sections.
2667 @c FIXME: ref to some other doc on obj-file formats could go here.
2670 @cindex relocation example
2671 An idealized example of three relocatable sections follows.
2673 The example uses the traditional section names @samp{.text} and @samp{.data}.
2675 Memory addresses are on the horizontal axis.
2679 @c END TEXI2ROFF-KILL
2682 partial program # 1: |ttttt|dddd|00|
2689 partial program # 2: |TTT|DDD|000|
2692 +--+---+-----+--+----+---+-----+~~
2693 linked program: | |TTT|ttttt| |dddd|DDD|00000|
2694 +--+---+-----+--+----+---+-----+~~
2696 addresses: 0 @dots{}
2703 \line{\it Partial program \#1: \hfil}
2704 \line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2705 \line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
2707 \line{\it Partial program \#2: \hfil}
2708 \line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2709 \line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
2711 \line{\it linked program: \hfil}
2712 \line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
2713 \line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
2714 ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
2715 DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
2717 \line{\it addresses: \hfil}
2721 @c END TEXI2ROFF-KILL
2724 @section Assembler Internal Sections
2726 @cindex internal assembler sections
2727 @cindex sections in messages, internal
2728 These sections are meant only for the internal use of @command{@value{AS}}. They
2729 have no meaning at run-time. You do not really need to know about these
2730 sections for most purposes; but they can be mentioned in @command{@value{AS}}
2731 warning messages, so it might be helpful to have an idea of their
2732 meanings to @command{@value{AS}}. These sections are used to permit the
2733 value of every expression in your assembly language program to be a
2734 section-relative address.
2737 @cindex assembler internal logic error
2738 @item ASSEMBLER-INTERNAL-LOGIC-ERROR!
2739 An internal assembler logic error has been found. This means there is a
2740 bug in the assembler.
2742 @cindex expr (internal section)
2744 The assembler stores complex expression internally as combinations of
2745 symbols. When it needs to represent an expression as a symbol, it puts
2746 it in the expr section.
2748 @c FIXME item transfer[t] vector preload
2749 @c FIXME item transfer[t] vector postload
2750 @c FIXME item register
2754 @section Sub-Sections
2756 @cindex numbered subsections
2757 @cindex grouping data
2763 fall into two sections: text and data.
2765 You may have separate groups of
2767 data in named sections
2771 data in named sections
2777 that you want to end up near to each other in the object file, even though they
2778 are not contiguous in the assembler source. @command{@value{AS}} allows you to
2779 use @dfn{subsections} for this purpose. Within each section, there can be
2780 numbered subsections with values from 0 to 8192. Objects assembled into the
2781 same subsection go into the object file together with other objects in the same
2782 subsection. For example, a compiler might want to store constants in the text
2783 section, but might not want to have them interspersed with the program being
2784 assembled. In this case, the compiler could issue a @samp{.text 0} before each
2785 section of code being output, and a @samp{.text 1} before each group of
2786 constants being output.
2788 Subsections are optional. If you do not use subsections, everything
2789 goes in subsection number zero.
2792 Each subsection is zero-padded up to a multiple of four bytes.
2793 (Subsections may be padded a different amount on different flavors
2794 of @command{@value{AS}}.)
2798 On the H8/300 and H8/500 platforms, each subsection is zero-padded to a word
2799 boundary (two bytes).
2800 The same is true on the Hitachi SH.
2803 @c FIXME section padding (alignment)?
2804 @c Rich Pixley says padding here depends on target obj code format; that
2805 @c doesn't seem particularly useful to say without further elaboration,
2806 @c so for now I say nothing about it. If this is a generic BFD issue,
2807 @c these paragraphs might need to vanish from this manual, and be
2808 @c discussed in BFD chapter of binutils (or some such).
2811 On the AMD 29K family, no particular padding is added to section or
2812 subsection sizes; @value{AS} forces no alignment on this platform.
2816 Subsections appear in your object file in numeric order, lowest numbered
2817 to highest. (All this to be compatible with other people's assemblers.)
2818 The object file contains no representation of subsections; @code{@value{LD}} and
2819 other programs that manipulate object files see no trace of them.
2820 They just see all your text subsections as a text section, and all your
2821 data subsections as a data section.
2823 To specify which subsection you want subsequent statements assembled
2824 into, use a numeric argument to specify it, in a @samp{.text
2825 @var{expression}} or a @samp{.data @var{expression}} statement.
2828 When generating COFF output, you
2833 can also use an extra subsection
2834 argument with arbitrary named sections: @samp{.section @var{name},
2837 @var{Expression} should be an absolute expression.
2838 (@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0}
2839 is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
2840 begins in @code{text 0}. For instance:
2842 .text 0 # The default subsection is text 0 anyway.
2843 .ascii "This lives in the first text subsection. *"
2845 .ascii "But this lives in the second text subsection."
2847 .ascii "This lives in the data section,"
2848 .ascii "in the first data subsection."
2850 .ascii "This lives in the first text section,"
2851 .ascii "immediately following the asterisk (*)."
2854 Each section has a @dfn{location counter} incremented by one for every byte
2855 assembled into that section. Because subsections are merely a convenience
2856 restricted to @command{@value{AS}} there is no concept of a subsection location
2857 counter. There is no way to directly manipulate a location counter---but the
2858 @code{.align} directive changes it, and any label definition captures its
2859 current value. The location counter of the section where statements are being
2860 assembled is said to be the @dfn{active} location counter.
2863 @section bss Section
2866 @cindex common variable storage
2867 The bss section is used for local common variable storage.
2868 You may allocate address space in the bss section, but you may
2869 not dictate data to load into it before your program executes. When
2870 your program starts running, all the contents of the bss
2871 section are zeroed bytes.
2873 The @code{.lcomm} pseudo-op defines a symbol in the bss section; see
2874 @ref{Lcomm,,@code{.lcomm}}.
2876 The @code{.comm} pseudo-op may be used to declare a common symbol, which is
2877 another form of uninitialized symbol; see @xref{Comm,,@code{.comm}}.
2880 When assembling for a target which supports multiple sections, such as ELF or
2881 COFF, you may switch into the @code{.bss} section and define symbols as usual;
2882 see @ref{Section,,@code{.section}}. You may only assemble zero values into the
2883 section. Typically the section will only contain symbol definitions and
2884 @code{.skip} directives (@pxref{Skip,,@code{.skip}}).
2891 Symbols are a central concept: the programmer uses symbols to name
2892 things, the linker uses symbols to link, and the debugger uses symbols
2896 @cindex debuggers, and symbol order
2897 @emph{Warning:} @command{@value{AS}} does not place symbols in the object file in
2898 the same order they were declared. This may break some debuggers.
2903 * Setting Symbols:: Giving Symbols Other Values
2904 * Symbol Names:: Symbol Names
2905 * Dot:: The Special Dot Symbol
2906 * Symbol Attributes:: Symbol Attributes
2913 A @dfn{label} is written as a symbol immediately followed by a colon
2914 @samp{:}. The symbol then represents the current value of the
2915 active location counter, and is, for example, a suitable instruction
2916 operand. You are warned if you use the same symbol to represent two
2917 different locations: the first definition overrides any other
2921 On the HPPA, the usual form for a label need not be immediately followed by a
2922 colon, but instead must start in column zero. Only one label may be defined on
2923 a single line. To work around this, the HPPA version of @command{@value{AS}} also
2924 provides a special directive @code{.label} for defining labels more flexibly.
2927 @node Setting Symbols
2928 @section Giving Symbols Other Values
2930 @cindex assigning values to symbols
2931 @cindex symbol values, assigning
2932 A symbol can be given an arbitrary value by writing a symbol, followed
2933 by an equals sign @samp{=}, followed by an expression
2934 (@pxref{Expressions}). This is equivalent to using the @code{.set}
2935 directive. @xref{Set,,@code{.set}}.
2938 @section Symbol Names
2940 @cindex symbol names
2941 @cindex names, symbol
2942 @ifclear SPECIAL-SYMS
2943 Symbol names begin with a letter or with one of @samp{._}. On most
2944 machines, you can also use @code{$} in symbol names; exceptions are
2945 noted in @ref{Machine Dependencies}. That character may be followed by any
2946 string of digits, letters, dollar signs (unless otherwise noted in
2947 @ref{Machine Dependencies}), and underscores.
2950 For the AMD 29K family, @samp{?} is also allowed in the
2951 body of a symbol name, though not at its beginning.
2956 Symbol names begin with a letter or with one of @samp{._}. On the
2958 H8/500, you can also use @code{$} in symbol names. That character may
2959 be followed by any string of digits, letters, dollar signs (save on the
2960 H8/300), and underscores.
2964 Case of letters is significant: @code{foo} is a different symbol name
2967 Each symbol has exactly one name. Each name in an assembly language program
2968 refers to exactly one symbol. You may use that symbol name any number of times
2971 @subheading Local Symbol Names
2973 @cindex local symbol names
2974 @cindex symbol names, local
2975 @cindex temporary symbol names
2976 @cindex symbol names, temporary
2977 Local symbols help compilers and programmers use names temporarily.
2978 They create symbols which are guaranteed to be unique over the entire scope of
2979 the input source code and which can be referred to by a simple notation.
2980 To define a local symbol, write a label of the form @samp{@b{N}:} (where @b{N}
2981 represents any positive integer). To refer to the most recent previous
2982 definition of that symbol write @samp{@b{N}b}, using the same number as when
2983 you defined the label. To refer to the next definition of a local label, write
2984 @samp{@b{N}f}--- The @samp{b} stands for``backwards'' and the @samp{f} stands
2987 There is no restriction on how you can use these labels, and you can reuse them
2988 too. So that it is possible to repeatedly define the same local label (using
2989 the same number @samp{@b{N}}), although you can only refer to the most recently
2990 defined local label of that number (for a backwards reference) or the next
2991 definition of a specific local label for a forward reference. It is also worth
2992 noting that the first 10 local labels (@samp{@b{0:}}@dots{}@samp{@b{9:}}) are
2993 implemented in a slightly more efficient manner than the others.
3004 Which is the equivalent of:
3007 label_1: branch label_3
3008 label_2: branch label_1
3009 label_3: branch label_4
3010 label_4: branch label_3
3013 Local symbol names are only a notational device. They are immediately
3014 transformed into more conventional symbol names before the assembler uses them.
3015 The symbol names stored in the symbol table, appearing in error messages and
3016 optionally emitted to the object file. The names are constructed using these
3021 All local labels begin with @samp{L}. Normally both @command{@value{AS}} and
3022 @code{@value{LD}} forget symbols that start with @samp{L}. These labels are
3023 used for symbols you are never intended to see. If you use the
3024 @samp{-L} option then @command{@value{AS}} retains these symbols in the
3025 object file. If you also instruct @code{@value{LD}} to retain these symbols,
3026 you may use them in debugging.
3029 This is the number that was used in the local label definition. So if the
3030 label is written @samp{55:} then the number is @samp{55}.
3033 This unusual character is included so you do not accidentally invent a symbol
3034 of the same name. The character has ASCII value of @samp{\002} (control-B).
3036 @item @emph{ordinal number}
3037 This is a serial number to keep the labels distinct. The first definition of
3038 @samp{0:} gets the number @samp{1}. The 15th definition of @samp{0:} gets the
3039 number @samp{15}, and so on. Likewise the first definition of @samp{1:} gets
3040 the number @samp{1} and its 15th defintion gets @samp{15} as well.
3043 So for example, the first @code{1:} is named @code{L1@kbd{C-B}1}, the 44th
3044 @code{3:} is named @code{L3@kbd{C-B}44}.
3046 @subheading Dollar Local Labels
3047 @cindex dollar local symbols
3049 @code{@value{AS}} also supports an even more local form of local labels called
3050 dollar labels. These labels go out of scope (ie they become undefined) as soon
3051 as a non-local label is defined. Thus they remain valid for only a small
3052 region of the input source code. Normal local labels, by contrast, remain in
3053 scope for the entire file, or until they are redefined by another occurrence of
3054 the same local label.
3056 Dollar labels are defined in exactly the same way as ordinary local labels,
3057 except that instead of being terminated by a colon, they are terminated by a
3058 dollar sign. eg @samp{@b{55$}}.
3060 They can also be distinguished from ordinary local labels by their transformed
3061 name which uses ASCII character @samp{\001} (control-A) as the magic character
3062 to distinguish them from ordinary labels. Thus the 5th defintion of @samp{6$}
3063 is named @samp{L6@kbd{C-A}5}.
3066 @section The Special Dot Symbol
3068 @cindex dot (symbol)
3069 @cindex @code{.} (symbol)
3070 @cindex current address
3071 @cindex location counter
3072 The special symbol @samp{.} refers to the current address that
3073 @command{@value{AS}} is assembling into. Thus, the expression @samp{melvin:
3074 .long .} defines @code{melvin} to contain its own address.
3075 Assigning a value to @code{.} is treated the same as a @code{.org}
3076 directive. Thus, the expression @samp{.=.+4} is the same as saying
3077 @ifclear no-space-dir
3086 @node Symbol Attributes
3087 @section Symbol Attributes
3089 @cindex symbol attributes
3090 @cindex attributes, symbol
3091 Every symbol has, as well as its name, the attributes ``Value'' and
3092 ``Type''. Depending on output format, symbols can also have auxiliary
3095 The detailed definitions are in @file{a.out.h}.
3098 If you use a symbol without defining it, @command{@value{AS}} assumes zero for
3099 all these attributes, and probably won't warn you. This makes the
3100 symbol an externally defined symbol, which is generally what you
3104 * Symbol Value:: Value
3105 * Symbol Type:: Type
3108 * a.out Symbols:: Symbol Attributes: @code{a.out}
3112 * a.out Symbols:: Symbol Attributes: @code{a.out}
3115 * a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out}
3120 * COFF Symbols:: Symbol Attributes for COFF
3123 * SOM Symbols:: Symbol Attributes for SOM
3130 @cindex value of a symbol
3131 @cindex symbol value
3132 The value of a symbol is (usually) 32 bits. For a symbol which labels a
3133 location in the text, data, bss or absolute sections the value is the
3134 number of addresses from the start of that section to the label.
3135 Naturally for text, data and bss sections the value of a symbol changes
3136 as @code{@value{LD}} changes section base addresses during linking. Absolute
3137 symbols' values do not change during linking: that is why they are
3140 The value of an undefined symbol is treated in a special way. If it is
3141 0 then the symbol is not defined in this assembler source file, and
3142 @code{@value{LD}} tries to determine its value from other files linked into the
3143 same program. You make this kind of symbol simply by mentioning a symbol
3144 name without defining it. A non-zero value represents a @code{.comm}
3145 common declaration. The value is how much common storage to reserve, in
3146 bytes (addresses). The symbol refers to the first address of the
3152 @cindex type of a symbol
3154 The type attribute of a symbol contains relocation (section)
3155 information, any flag settings indicating that a symbol is external, and
3156 (optionally), other information for linkers and debuggers. The exact
3157 format depends on the object-code output format in use.
3162 @c The following avoids a "widow" subsection title. @group would be
3163 @c better if it were available outside examples.
3166 @subsection Symbol Attributes: @code{a.out}, @code{b.out}
3168 @cindex @code{b.out} symbol attributes
3169 @cindex symbol attributes, @code{b.out}
3170 These symbol attributes appear only when @command{@value{AS}} is configured for
3171 one of the Berkeley-descended object output formats---@code{a.out} or
3177 @subsection Symbol Attributes: @code{a.out}
3179 @cindex @code{a.out} symbol attributes
3180 @cindex symbol attributes, @code{a.out}
3186 @subsection Symbol Attributes: @code{a.out}
3188 @cindex @code{a.out} symbol attributes
3189 @cindex symbol attributes, @code{a.out}
3193 * Symbol Desc:: Descriptor
3194 * Symbol Other:: Other
3198 @subsubsection Descriptor
3200 @cindex descriptor, of @code{a.out} symbol
3201 This is an arbitrary 16-bit value. You may establish a symbol's
3202 descriptor value by using a @code{.desc} statement
3203 (@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
3204 @command{@value{AS}}.
3207 @subsubsection Other
3209 @cindex other attribute, of @code{a.out} symbol
3210 This is an arbitrary 8-bit value. It means nothing to @command{@value{AS}}.
3215 @subsection Symbol Attributes for COFF
3217 @cindex COFF symbol attributes
3218 @cindex symbol attributes, COFF
3220 The COFF format supports a multitude of auxiliary symbol attributes;
3221 like the primary symbol attributes, they are set between @code{.def} and
3222 @code{.endef} directives.
3224 @subsubsection Primary Attributes
3226 @cindex primary attributes, COFF symbols
3227 The symbol name is set with @code{.def}; the value and type,
3228 respectively, with @code{.val} and @code{.type}.
3230 @subsubsection Auxiliary Attributes
3232 @cindex auxiliary attributes, COFF symbols
3233 The @command{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
3234 @code{.size}, and @code{.tag} can generate auxiliary symbol table
3235 information for COFF.
3240 @subsection Symbol Attributes for SOM
3242 @cindex SOM symbol attributes
3243 @cindex symbol attributes, SOM
3245 The SOM format for the HPPA supports a multitude of symbol attributes set with
3246 the @code{.EXPORT} and @code{.IMPORT} directives.
3248 The attributes are described in @cite{HP9000 Series 800 Assembly
3249 Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
3250 @code{EXPORT} assembler directive documentation.
3254 @chapter Expressions
3258 @cindex numeric values
3259 An @dfn{expression} specifies an address or numeric value.
3260 Whitespace may precede and/or follow an expression.
3262 The result of an expression must be an absolute number, or else an offset into
3263 a particular section. If an expression is not absolute, and there is not
3264 enough information when @command{@value{AS}} sees the expression to know its
3265 section, a second pass over the source program might be necessary to interpret
3266 the expression---but the second pass is currently not implemented.
3267 @command{@value{AS}} aborts with an error message in this situation.
3270 * Empty Exprs:: Empty Expressions
3271 * Integer Exprs:: Integer Expressions
3275 @section Empty Expressions
3277 @cindex empty expressions
3278 @cindex expressions, empty
3279 An empty expression has no value: it is just whitespace or null.
3280 Wherever an absolute expression is required, you may omit the
3281 expression, and @command{@value{AS}} assumes a value of (absolute) 0. This
3282 is compatible with other assemblers.
3285 @section Integer Expressions
3287 @cindex integer expressions
3288 @cindex expressions, integer
3289 An @dfn{integer expression} is one or more @emph{arguments} delimited
3290 by @emph{operators}.
3293 * Arguments:: Arguments
3294 * Operators:: Operators
3295 * Prefix Ops:: Prefix Operators
3296 * Infix Ops:: Infix Operators
3300 @subsection Arguments
3302 @cindex expression arguments
3303 @cindex arguments in expressions
3304 @cindex operands in expressions
3305 @cindex arithmetic operands
3306 @dfn{Arguments} are symbols, numbers or subexpressions. In other
3307 contexts arguments are sometimes called ``arithmetic operands''. In
3308 this manual, to avoid confusing them with the ``instruction operands'' of
3309 the machine language, we use the term ``argument'' to refer to parts of
3310 expressions only, reserving the word ``operand'' to refer only to machine
3311 instruction operands.
3313 Symbols are evaluated to yield @{@var{section} @var{NNN}@} where
3314 @var{section} is one of text, data, bss, absolute,
3315 or undefined. @var{NNN} is a signed, 2's complement 32 bit
3318 Numbers are usually integers.
3320 A number can be a flonum or bignum. In this case, you are warned
3321 that only the low order 32 bits are used, and @command{@value{AS}} pretends
3322 these 32 bits are an integer. You may write integer-manipulating
3323 instructions that act on exotic constants, compatible with other
3326 @cindex subexpressions
3327 Subexpressions are a left parenthesis @samp{(} followed by an integer
3328 expression, followed by a right parenthesis @samp{)}; or a prefix
3329 operator followed by an argument.
3332 @subsection Operators
3334 @cindex operators, in expressions
3335 @cindex arithmetic functions
3336 @cindex functions, in expressions
3337 @dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
3338 operators are followed by an argument. Infix operators appear
3339 between their arguments. Operators may be preceded and/or followed by
3343 @subsection Prefix Operator
3345 @cindex prefix operators
3346 @command{@value{AS}} has the following @dfn{prefix operators}. They each take
3347 one argument, which must be absolute.
3349 @c the tex/end tex stuff surrounding this small table is meant to make
3350 @c it align, on the printed page, with the similar table in the next
3351 @c section (which is inside an enumerate).
3353 \global\advance\leftskip by \itemindent
3358 @dfn{Negation}. Two's complement negation.
3360 @dfn{Complementation}. Bitwise not.
3364 \global\advance\leftskip by -\itemindent
3368 @subsection Infix Operators
3370 @cindex infix operators
3371 @cindex operators, permitted arguments
3372 @dfn{Infix operators} take two arguments, one on either side. Operators
3373 have precedence, but operations with equal precedence are performed left
3374 to right. Apart from @code{+} or @option{-}, both arguments must be
3375 absolute, and the result is absolute.
3378 @cindex operator precedence
3379 @cindex precedence of operators
3386 @dfn{Multiplication}.
3389 @dfn{Division}. Truncation is the same as the C operator @samp{/}
3396 @dfn{Shift Left}. Same as the C operator @samp{<<}.
3400 @dfn{Shift Right}. Same as the C operator @samp{>>}.
3404 Intermediate precedence
3409 @dfn{Bitwise Inclusive Or}.
3415 @dfn{Bitwise Exclusive Or}.
3418 @dfn{Bitwise Or Not}.
3425 @cindex addition, permitted arguments
3426 @cindex plus, permitted arguments
3427 @cindex arguments for addition
3429 @dfn{Addition}. If either argument is absolute, the result has the section of
3430 the other argument. You may not add together arguments from different
3433 @cindex subtraction, permitted arguments
3434 @cindex minus, permitted arguments
3435 @cindex arguments for subtraction
3437 @dfn{Subtraction}. If the right argument is absolute, the
3438 result has the section of the left argument.
3439 If both arguments are in the same section, the result is absolute.
3440 You may not subtract arguments from different sections.
3441 @c FIXME is there still something useful to say about undefined - undefined ?
3443 @cindex comparison expressions
3444 @cindex expressions, comparison
3448 @dfn{Is Not Equal To}
3452 @dfn{Is Greater Than}
3454 @dfn{Is Greater Than Or Equal To}
3456 @dfn{Is Less Than Or Equal To}
3458 The comparison operators can be used as infix operators. A true results has a
3459 value of -1 whereas a false result has a value of 0. Note, these operators
3460 perform signed comparisons.
3463 @item Lowest Precedence
3472 These two logical operations can be used to combine the results of sub
3473 expressions. Note, unlike the comparison operators a true result returns a
3474 value of 1 but a false results does still return 0. Also note that the logical
3475 or operator has a slightly lower precedence than logical and.
3480 In short, it's only meaningful to add or subtract the @emph{offsets} in an
3481 address; you can only have a defined section in one of the two arguments.
3484 @chapter Assembler Directives
3486 @cindex directives, machine independent
3487 @cindex pseudo-ops, machine independent
3488 @cindex machine independent directives
3489 All assembler directives have names that begin with a period (@samp{.}).
3490 The rest of the name is letters, usually in lower case.
3492 This chapter discusses directives that are available regardless of the
3493 target machine configuration for the @sc{gnu} assembler.
3495 Some machine configurations provide additional directives.
3496 @xref{Machine Dependencies}.
3499 @ifset machine-directives
3500 @xref{Machine Dependencies} for additional directives.
3505 * Abort:: @code{.abort}
3507 * ABORT:: @code{.ABORT}
3510 * Align:: @code{.align @var{abs-expr} , @var{abs-expr}}
3511 * Ascii:: @code{.ascii "@var{string}"}@dots{}
3512 * Asciz:: @code{.asciz "@var{string}"}@dots{}
3513 * Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}}
3514 * Byte:: @code{.byte @var{expressions}}
3515 * Comm:: @code{.comm @var{symbol} , @var{length} }
3516 * Data:: @code{.data @var{subsection}}
3518 * Def:: @code{.def @var{name}}
3521 * Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
3527 * Double:: @code{.double @var{flonums}}
3528 * Eject:: @code{.eject}
3529 * Else:: @code{.else}
3530 * Elseif:: @code{.elseif}
3533 * Endef:: @code{.endef}
3536 * Endfunc:: @code{.endfunc}
3537 * Endif:: @code{.endif}
3538 * Equ:: @code{.equ @var{symbol}, @var{expression}}
3539 * Equiv:: @code{.equiv @var{symbol}, @var{expression}}
3541 * Exitm:: @code{.exitm}
3542 * Extern:: @code{.extern}
3543 * Fail:: @code{.fail}
3544 @ifclear no-file-dir
3545 * File:: @code{.file @var{string}}
3548 * Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}}
3549 * Float:: @code{.float @var{flonums}}
3550 * Func:: @code{.func}
3551 * Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}}
3553 * Hidden:: @code{.hidden @var{names}}
3556 * hword:: @code{.hword @var{expressions}}
3557 * Ident:: @code{.ident}
3558 * If:: @code{.if @var{absolute expression}}
3559 * Incbin:: @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
3560 * Include:: @code{.include "@var{file}"}
3561 * Int:: @code{.int @var{expressions}}
3563 * Internal:: @code{.internal @var{names}}
3566 * Irp:: @code{.irp @var{symbol},@var{values}}@dots{}
3567 * Irpc:: @code{.irpc @var{symbol},@var{values}}@dots{}
3568 * Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
3569 * Lflags:: @code{.lflags}
3570 @ifclear no-line-dir
3571 * Line:: @code{.line @var{line-number}}
3574 * Ln:: @code{.ln @var{line-number}}
3575 * Linkonce:: @code{.linkonce [@var{type}]}
3576 * List:: @code{.list}
3577 * Long:: @code{.long @var{expressions}}
3579 * Lsym:: @code{.lsym @var{symbol}, @var{expression}}
3582 * Macro:: @code{.macro @var{name} @var{args}}@dots{}
3583 * MRI:: @code{.mri @var{val}}
3584 * Nolist:: @code{.nolist}
3585 * Octa:: @code{.octa @var{bignums}}
3586 * Org:: @code{.org @var{new-lc} , @var{fill}}
3587 * P2align:: @code{.p2align @var{abs-expr} , @var{abs-expr}}
3589 * PopSection:: @code{.popsection}
3590 * Previous:: @code{.previous}
3593 * Print:: @code{.print @var{string}}
3595 * Protected:: @code{.protected @var{names}}
3598 * Psize:: @code{.psize @var{lines}, @var{columns}}
3599 * Purgem:: @code{.purgem @var{name}}
3601 * PushSection:: @code{.pushsection @var{name}}
3604 * Quad:: @code{.quad @var{bignums}}
3605 * Rept:: @code{.rept @var{count}}
3606 * Sbttl:: @code{.sbttl "@var{subheading}"}
3608 * Scl:: @code{.scl @var{class}}
3609 * Section:: @code{.section @var{name}, @var{subsection}}
3612 * Set:: @code{.set @var{symbol}, @var{expression}}
3613 * Short:: @code{.short @var{expressions}}
3614 * Single:: @code{.single @var{flonums}}
3615 * Size:: @code{.size [@var{name} , @var{expression}]}
3616 * Skip:: @code{.skip @var{size} , @var{fill}}
3617 * Sleb128:: @code{.sleb128 @var{expressions}}
3618 * Space:: @code{.space @var{size} , @var{fill}}
3620 * Stab:: @code{.stabd, .stabn, .stabs}
3623 * String:: @code{.string "@var{str}"}
3624 * Struct:: @code{.struct @var{expression}}
3626 * SubSection:: @code{.subsection}
3627 * Symver:: @code{.symver @var{name},@var{name2@@nodename}}
3631 * Tag:: @code{.tag @var{structname}}
3634 * Text:: @code{.text @var{subsection}}
3635 * Title:: @code{.title "@var{heading}"}
3636 * Type:: @code{.type <@var{int} | @var{name} , @var{type description}>}
3637 * Uleb128:: @code{.uleb128 @var{expressions}}
3639 * Val:: @code{.val @var{addr}}
3643 * Version:: @code{.version "@var{string}"}
3644 * VTableEntry:: @code{.vtable_entry @var{table}, @var{offset}}
3645 * VTableInherit:: @code{.vtable_inherit @var{child}, @var{parent}}
3646 * Weak:: @code{.weak @var{names}}
3649 * Word:: @code{.word @var{expressions}}
3650 * Deprecated:: Deprecated Directives
3654 @section @code{.abort}
3656 @cindex @code{abort} directive
3657 @cindex stopping the assembly
3658 This directive stops the assembly immediately. It is for
3659 compatibility with other assemblers. The original idea was that the
3660 assembly language source would be piped into the assembler. If the sender
3661 of the source quit, it could use this directive tells @command{@value{AS}} to
3662 quit also. One day @code{.abort} will not be supported.
3666 @section @code{.ABORT}
3668 @cindex @code{ABORT} directive
3669 When producing COFF output, @command{@value{AS}} accepts this directive as a
3670 synonym for @samp{.abort}.
3673 When producing @code{b.out} output, @command{@value{AS}} accepts this directive,
3679 @section @code{.align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3681 @cindex padding the location counter
3682 @cindex @code{align} directive
3683 Pad the location counter (in the current subsection) to a particular storage
3684 boundary. The first expression (which must be absolute) is the alignment
3685 required, as described below.
3687 The second expression (also absolute) gives the fill value to be stored in the
3688 padding bytes. It (and the comma) may be omitted. If it is omitted, the
3689 padding bytes are normally zero. However, on some systems, if the section is
3690 marked as containing code and the fill value is omitted, the space is filled
3691 with no-op instructions.
3693 The third expression is also absolute, and is also optional. If it is present,
3694 it is the maximum number of bytes that should be skipped by this alignment
3695 directive. If doing the alignment would require skipping more bytes than the
3696 specified maximum, then the alignment is not done at all. You can omit the
3697 fill value (the second argument) entirely by simply using two commas after the
3698 required alignment; this can be useful if you want the alignment to be filled
3699 with no-op instructions when appropriate.
3701 The way the required alignment is specified varies from system to system.
3702 For the a29k, hppa, m68k, m88k, w65, sparc, and Hitachi SH, and i386 using ELF
3704 the first expression is the
3705 alignment request in bytes. For example @samp{.align 8} advances
3706 the location counter until it is a multiple of 8. If the location counter
3707 is already a multiple of 8, no change is needed.
3709 For other systems, including the i386 using a.out format, and the arm and
3710 strongarm, it is the
3711 number of low-order zero bits the location counter must have after
3712 advancement. For example @samp{.align 3} advances the location
3713 counter until it a multiple of 8. If the location counter is already a
3714 multiple of 8, no change is needed.
3716 This inconsistency is due to the different behaviors of the various
3717 native assemblers for these systems which GAS must emulate.
3718 GAS also provides @code{.balign} and @code{.p2align} directives,
3719 described later, which have a consistent behavior across all
3720 architectures (but are specific to GAS).
3723 @section @code{.ascii "@var{string}"}@dots{}
3725 @cindex @code{ascii} directive
3726 @cindex string literals
3727 @code{.ascii} expects zero or more string literals (@pxref{Strings})
3728 separated by commas. It assembles each string (with no automatic
3729 trailing zero byte) into consecutive addresses.
3732 @section @code{.asciz "@var{string}"}@dots{}
3734 @cindex @code{asciz} directive
3735 @cindex zero-terminated strings
3736 @cindex null-terminated strings
3737 @code{.asciz} is just like @code{.ascii}, but each string is followed by
3738 a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
3741 @section @code{.balign[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3743 @cindex padding the location counter given number of bytes
3744 @cindex @code{balign} directive
3745 Pad the location counter (in the current subsection) to a particular
3746 storage boundary. The first expression (which must be absolute) is the
3747 alignment request in bytes. For example @samp{.balign 8} advances
3748 the location counter until it is a multiple of 8. If the location counter
3749 is already a multiple of 8, no change is needed.
3751 The second expression (also absolute) gives the fill value to be stored in the
3752 padding bytes. It (and the comma) may be omitted. If it is omitted, the
3753 padding bytes are normally zero. However, on some systems, if the section is
3754 marked as containing code and the fill value is omitted, the space is filled
3755 with no-op instructions.
3757 The third expression is also absolute, and is also optional. If it is present,
3758 it is the maximum number of bytes that should be skipped by this alignment
3759 directive. If doing the alignment would require skipping more bytes than the
3760 specified maximum, then the alignment is not done at all. You can omit the
3761 fill value (the second argument) entirely by simply using two commas after the
3762 required alignment; this can be useful if you want the alignment to be filled
3763 with no-op instructions when appropriate.
3765 @cindex @code{balignw} directive
3766 @cindex @code{balignl} directive
3767 The @code{.balignw} and @code{.balignl} directives are variants of the
3768 @code{.balign} directive. The @code{.balignw} directive treats the fill
3769 pattern as a two byte word value. The @code{.balignl} directives treats the
3770 fill pattern as a four byte longword value. For example, @code{.balignw
3771 4,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
3772 filled in with the value 0x368d (the exact placement of the bytes depends upon
3773 the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
3777 @section @code{.byte @var{expressions}}
3779 @cindex @code{byte} directive
3780 @cindex integers, one byte
3781 @code{.byte} expects zero or more expressions, separated by commas.
3782 Each expression is assembled into the next byte.
3785 @section @code{.comm @var{symbol} , @var{length} }
3787 @cindex @code{comm} directive
3788 @cindex symbol, common
3789 @code{.comm} declares a common symbol named @var{symbol}. When linking, a
3790 common symbol in one object file may be merged with a defined or common symbol
3791 of the same name in another object file. If @code{@value{LD}} does not see a
3792 definition for the symbol--just one or more common symbols--then it will
3793 allocate @var{length} bytes of uninitialized memory. @var{length} must be an
3794 absolute expression. If @code{@value{LD}} sees multiple common symbols with
3795 the same name, and they do not all have the same size, it will allocate space
3796 using the largest size.
3799 When using ELF, the @code{.comm} directive takes an optional third argument.
3800 This is the desired alignment of the symbol, specified as a byte boundary (for
3801 example, an alignment of 16 means that the least significant 4 bits of the
3802 address should be zero). The alignment must be an absolute expression, and it
3803 must be a power of two. If @code{@value{LD}} allocates uninitialized memory
3804 for the common symbol, it will use the alignment when placing the symbol. If
3805 no alignment is specified, @command{@value{AS}} will set the alignment to the
3806 largest power of two less than or equal to the size of the symbol, up to a
3811 The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
3812 @samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
3816 @section @code{.data @var{subsection}}
3818 @cindex @code{data} directive
3819 @code{.data} tells @command{@value{AS}} to assemble the following statements onto the
3820 end of the data subsection numbered @var{subsection} (which is an
3821 absolute expression). If @var{subsection} is omitted, it defaults
3826 @section @code{.def @var{name}}
3828 @cindex @code{def} directive
3829 @cindex COFF symbols, debugging
3830 @cindex debugging COFF symbols
3831 Begin defining debugging information for a symbol @var{name}; the
3832 definition extends until the @code{.endef} directive is encountered.
3835 This directive is only observed when @command{@value{AS}} is configured for COFF
3836 format output; when producing @code{b.out}, @samp{.def} is recognized,
3843 @section @code{.desc @var{symbol}, @var{abs-expression}}
3845 @cindex @code{desc} directive
3846 @cindex COFF symbol descriptor
3847 @cindex symbol descriptor, COFF
3848 This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
3849 to the low 16 bits of an absolute expression.
3852 The @samp{.desc} directive is not available when @command{@value{AS}} is
3853 configured for COFF output; it is only for @code{a.out} or @code{b.out}
3854 object format. For the sake of compatibility, @command{@value{AS}} accepts
3855 it, but produces no output, when configured for COFF.
3861 @section @code{.dim}
3863 @cindex @code{dim} directive
3864 @cindex COFF auxiliary symbol information
3865 @cindex auxiliary symbol information, COFF
3866 This directive is generated by compilers to include auxiliary debugging
3867 information in the symbol table. It is only permitted inside
3868 @code{.def}/@code{.endef} pairs.
3871 @samp{.dim} is only meaningful when generating COFF format output; when
3872 @command{@value{AS}} is generating @code{b.out}, it accepts this directive but
3878 @section @code{.double @var{flonums}}
3880 @cindex @code{double} directive
3881 @cindex floating point numbers (double)
3882 @code{.double} expects zero or more flonums, separated by commas. It
3883 assembles floating point numbers.
3885 The exact kind of floating point numbers emitted depends on how
3886 @command{@value{AS}} is configured. @xref{Machine Dependencies}.
3890 On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers
3891 in @sc{ieee} format.
3896 @section @code{.eject}
3898 @cindex @code{eject} directive
3899 @cindex new page, in listings
3900 @cindex page, in listings
3901 @cindex listing control: new page
3902 Force a page break at this point, when generating assembly listings.
3905 @section @code{.else}
3907 @cindex @code{else} directive
3908 @code{.else} is part of the @command{@value{AS}} support for conditional
3909 assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section
3910 of code to be assembled if the condition for the preceding @code{.if}
3914 @section @code{.elseif}
3916 @cindex @code{elseif} directive
3917 @code{.elseif} is part of the @command{@value{AS}} support for conditional
3918 assembly; @pxref{If,,@code{.if}}. It is shorthand for beginning a new
3919 @code{.if} block that would otherwise fill the entire @code{.else} section.
3922 @section @code{.end}
3924 @cindex @code{end} directive
3925 @code{.end} marks the end of the assembly file. @command{@value{AS}} does not
3926 process anything in the file past the @code{.end} directive.
3930 @section @code{.endef}
3932 @cindex @code{endef} directive
3933 This directive flags the end of a symbol definition begun with
3937 @samp{.endef} is only meaningful when generating COFF format output; if
3938 @command{@value{AS}} is configured to generate @code{b.out}, it accepts this
3939 directive but ignores it.
3944 @section @code{.endfunc}
3945 @cindex @code{endfunc} directive
3946 @code{.endfunc} marks the end of a function specified with @code{.func}.
3949 @section @code{.endif}
3951 @cindex @code{endif} directive
3952 @code{.endif} is part of the @command{@value{AS}} support for conditional assembly;
3953 it marks the end of a block of code that is only assembled
3954 conditionally. @xref{If,,@code{.if}}.
3957 @section @code{.equ @var{symbol}, @var{expression}}
3959 @cindex @code{equ} directive
3960 @cindex assigning values to symbols
3961 @cindex symbols, assigning values to
3962 This directive sets the value of @var{symbol} to @var{expression}.
3963 It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
3966 The syntax for @code{equ} on the HPPA is
3967 @samp{@var{symbol} .equ @var{expression}}.
3971 @section @code{.equiv @var{symbol}, @var{expression}}
3972 @cindex @code{equiv} directive
3973 The @code{.equiv} directive is like @code{.equ} and @code{.set}, except that
3974 the assembler will signal an error if @var{symbol} is already defined.
3976 Except for the contents of the error message, this is roughly equivalent to
3985 @section @code{.err}
3986 @cindex @code{err} directive
3987 If @command{@value{AS}} assembles a @code{.err} directive, it will print an error
3988 message and, unless the @option{-Z} option was used, it will not generate an
3989 object file. This can be used to signal error an conditionally compiled code.
3992 @section @code{.exitm}
3993 Exit early from the current macro definition. @xref{Macro}.
3996 @section @code{.extern}
3998 @cindex @code{extern} directive
3999 @code{.extern} is accepted in the source program---for compatibility
4000 with other assemblers---but it is ignored. @command{@value{AS}} treats
4001 all undefined symbols as external.
4004 @section @code{.fail @var{expression}}
4006 @cindex @code{fail} directive
4007 Generates an error or a warning. If the value of the @var{expression} is 500
4008 or more, @command{@value{AS}} will print a warning message. If the value is less
4009 than 500, @command{@value{AS}} will print an error message. The message will
4010 include the value of @var{expression}. This can occasionally be useful inside
4011 complex nested macros or conditional assembly.
4013 @ifclear no-file-dir
4015 @section @code{.file @var{string}}
4017 @cindex @code{file} directive
4018 @cindex logical file name
4019 @cindex file name, logical
4020 @code{.file} tells @command{@value{AS}} that we are about to start a new logical
4021 file. @var{string} is the new file name. In general, the filename is
4022 recognized whether or not it is surrounded by quotes @samp{"}; but if you wish
4023 to specify an empty file name, you must give the quotes--@code{""}. This
4024 statement may go away in future: it is only recognized to be compatible with
4025 old @command{@value{AS}} programs.
4027 In some configurations of @command{@value{AS}}, @code{.file} has already been
4028 removed to avoid conflicts with other assemblers. @xref{Machine Dependencies}.
4033 @section @code{.fill @var{repeat} , @var{size} , @var{value}}
4035 @cindex @code{fill} directive
4036 @cindex writing patterns in memory
4037 @cindex patterns, writing in memory
4038 @var{repeat}, @var{size} and @var{value} are absolute expressions.
4039 This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
4040 may be zero or more. @var{Size} may be zero or more, but if it is
4041 more than 8, then it is deemed to have the value 8, compatible with
4042 other people's assemblers. The contents of each @var{repeat} bytes
4043 is taken from an 8-byte number. The highest order 4 bytes are
4044 zero. The lowest order 4 bytes are @var{value} rendered in the
4045 byte-order of an integer on the computer @command{@value{AS}} is assembling for.
4046 Each @var{size} bytes in a repetition is taken from the lowest order
4047 @var{size} bytes of this number. Again, this bizarre behavior is
4048 compatible with other people's assemblers.
4050 @var{size} and @var{value} are optional.
4051 If the second comma and @var{value} are absent, @var{value} is
4052 assumed zero. If the first comma and following tokens are absent,
4053 @var{size} is assumed to be 1.
4056 @section @code{.float @var{flonums}}
4058 @cindex floating point numbers (single)
4059 @cindex @code{float} directive
4060 This directive assembles zero or more flonums, separated by commas. It
4061 has the same effect as @code{.single}.
4063 The exact kind of floating point numbers emitted depends on how
4064 @command{@value{AS}} is configured.
4065 @xref{Machine Dependencies}.
4069 On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers
4070 in @sc{ieee} format.
4075 @section @code{.func @var{name}[,@var{label}]}
4076 @cindex @code{func} directive
4077 @code{.func} emits debugging information to denote function @var{name}, and
4078 is ignored unless the file is assembled with debugging enabled.
4079 Only @samp{--gstabs} is currently supported.
4080 @var{label} is the entry point of the function and if omitted @var{name}
4081 prepended with the @samp{leading char} is used.
4082 @samp{leading char} is usually @code{_} or nothing, depending on the target.
4083 All functions are currently defined to have @code{void} return type.
4084 The function must be terminated with @code{.endfunc}.
4087 @section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
4089 @cindex @code{global} directive
4090 @cindex symbol, making visible to linker
4091 @code{.global} makes the symbol visible to @code{@value{LD}}. If you define
4092 @var{symbol} in your partial program, its value is made available to
4093 other partial programs that are linked with it. Otherwise,
4094 @var{symbol} takes its attributes from a symbol of the same name
4095 from another file linked into the same program.
4097 Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
4098 compatibility with other assemblers.
4101 On the HPPA, @code{.global} is not always enough to make it accessible to other
4102 partial programs. You may need the HPPA-only @code{.EXPORT} directive as well.
4103 @xref{HPPA Directives,, HPPA Assembler Directives}.
4108 @section @code{.hidden @var{names}}
4110 @cindex @code{.hidden} directive
4112 This one of the ELF visibility directives. The other two are
4113 @code{.internal} (@pxref{Internal,,@code{.internal}}) and
4114 @code{.protected} (@pxref{Protected,,@code{.protected}}).
4116 This directive overrides the named symbols default visibility (which is set by
4117 their binding: local, global or weak). The directive sets the visibility to
4118 @code{hidden} which means that the symbols are not visible to other components.
4119 Such symbols are always considered to be @code{protected} as well.
4123 @section @code{.hword @var{expressions}}
4125 @cindex @code{hword} directive
4126 @cindex integers, 16-bit
4127 @cindex numbers, 16-bit
4128 @cindex sixteen bit integers
4129 This expects zero or more @var{expressions}, and emits
4130 a 16 bit number for each.
4133 This directive is a synonym for @samp{.short}; depending on the target
4134 architecture, it may also be a synonym for @samp{.word}.
4138 This directive is a synonym for @samp{.short}.
4141 This directive is a synonym for both @samp{.short} and @samp{.word}.
4146 @section @code{.ident}
4148 @cindex @code{ident} directive
4149 This directive is used by some assemblers to place tags in object files.
4150 @command{@value{AS}} simply accepts the directive for source-file
4151 compatibility with such assemblers, but does not actually emit anything
4155 @section @code{.if @var{absolute expression}}
4157 @cindex conditional assembly
4158 @cindex @code{if} directive
4159 @code{.if} marks the beginning of a section of code which is only
4160 considered part of the source program being assembled if the argument
4161 (which must be an @var{absolute expression}) is non-zero. The end of
4162 the conditional section of code must be marked by @code{.endif}
4163 (@pxref{Endif,,@code{.endif}}); optionally, you may include code for the
4164 alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}).
4165 If you have several conditions to check, @code{.elseif} may be used to avoid
4166 nesting blocks if/else within each subsequent @code{.else} block.
4168 The following variants of @code{.if} are also supported:
4170 @cindex @code{ifdef} directive
4171 @item .ifdef @var{symbol}
4172 Assembles the following section of code if the specified @var{symbol}
4175 @cindex @code{ifc} directive
4176 @item .ifc @var{string1},@var{string2}
4177 Assembles the following section of code if the two strings are the same. The
4178 strings may be optionally quoted with single quotes. If they are not quoted,
4179 the first string stops at the first comma, and the second string stops at the
4180 end of the line. Strings which contain whitespace should be quoted. The
4181 string comparison is case sensitive.
4183 @cindex @code{ifeq} directive
4184 @item .ifeq @var{absolute expression}
4185 Assembles the following section of code if the argument is zero.
4187 @cindex @code{ifeqs} directive
4188 @item .ifeqs @var{string1},@var{string2}
4189 Another form of @code{.ifc}. The strings must be quoted using double quotes.
4191 @cindex @code{ifge} directive
4192 @item .ifge @var{absolute expression}
4193 Assembles the following section of code if the argument is greater than or
4196 @cindex @code{ifgt} directive
4197 @item .ifgt @var{absolute expression}
4198 Assembles the following section of code if the argument is greater than zero.
4200 @cindex @code{ifle} directive
4201 @item .ifle @var{absolute expression}
4202 Assembles the following section of code if the argument is less than or equal
4205 @cindex @code{iflt} directive
4206 @item .iflt @var{absolute expression}
4207 Assembles the following section of code if the argument is less than zero.
4209 @cindex @code{ifnc} directive
4210 @item .ifnc @var{string1},@var{string2}.
4211 Like @code{.ifc}, but the sense of the test is reversed: this assembles the
4212 following section of code if the two strings are not the same.
4214 @cindex @code{ifndef} directive
4215 @cindex @code{ifnotdef} directive
4216 @item .ifndef @var{symbol}
4217 @itemx .ifnotdef @var{symbol}
4218 Assembles the following section of code if the specified @var{symbol}
4219 has not been defined. Both spelling variants are equivalent.
4221 @cindex @code{ifne} directive
4222 @item .ifne @var{absolute expression}
4223 Assembles the following section of code if the argument is not equal to zero
4224 (in other words, this is equivalent to @code{.if}).
4226 @cindex @code{ifnes} directive
4227 @item .ifnes @var{string1},@var{string2}
4228 Like @code{.ifeqs}, but the sense of the test is reversed: this assembles the
4229 following section of code if the two strings are not the same.
4233 @section @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
4235 @cindex @code{incbin} directive
4236 @cindex binary files, including
4237 The @code{incbin} directive includes @var{file} verbatim at the current
4238 location. You can control the search paths used with the @samp{-I} command-line
4239 option (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4242 The @var{skip} argument skips a number of bytes from the start of the
4243 @var{file}. The @var{count} argument indicates the maximum number of bytes to
4244 read. Note that the data is not aligned in any way, so it is the user's
4245 responsibility to make sure that proper alignment is provided both before and
4246 after the @code{incbin} directive.
4249 @section @code{.include "@var{file}"}
4251 @cindex @code{include} directive
4252 @cindex supporting files, including
4253 @cindex files, including
4254 This directive provides a way to include supporting files at specified
4255 points in your source program. The code from @var{file} is assembled as
4256 if it followed the point of the @code{.include}; when the end of the
4257 included file is reached, assembly of the original file continues. You
4258 can control the search paths used with the @samp{-I} command-line option
4259 (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4263 @section @code{.int @var{expressions}}
4265 @cindex @code{int} directive
4266 @cindex integers, 32-bit
4267 Expect zero or more @var{expressions}, of any section, separated by commas.
4268 For each expression, emit a number that, at run time, is the value of that
4269 expression. The byte order and bit size of the number depends on what kind
4270 of target the assembly is for.
4274 On the H8/500 and most forms of the H8/300, @code{.int} emits 16-bit
4275 integers. On the H8/300H and the Hitachi SH, however, @code{.int} emits
4282 @section @code{.internal @var{names}}
4284 @cindex @code{.internal} directive
4286 This one of the ELF visibility directives. The other two are
4287 @code{.hidden} (@pxref{Hidden,,@code{.hidden}}) and
4288 @code{.protected} (@pxref{Protected,,@code{.protected}}).
4290 This directive overrides the named symbols default visibility (which is set by
4291 their binding: local, global or weak). The directive sets the visibility to
4292 @code{internal} which means that the symbols are considered to be @code{hidden}
4293 (ie not visible to other components), and that some extra, processor specific
4294 processing must also be performed upon the symbols as well.
4298 @section @code{.irp @var{symbol},@var{values}}@dots{}
4300 @cindex @code{irp} directive
4301 Evaluate a sequence of statements assigning different values to @var{symbol}.
4302 The sequence of statements starts at the @code{.irp} directive, and is
4303 terminated by an @code{.endr} directive. For each @var{value}, @var{symbol} is
4304 set to @var{value}, and the sequence of statements is assembled. If no
4305 @var{value} is listed, the sequence of statements is assembled once, with
4306 @var{symbol} set to the null string. To refer to @var{symbol} within the
4307 sequence of statements, use @var{\symbol}.
4309 For example, assembling
4317 is equivalent to assembling
4326 @section @code{.irpc @var{symbol},@var{values}}@dots{}
4328 @cindex @code{irpc} directive
4329 Evaluate a sequence of statements assigning different values to @var{symbol}.
4330 The sequence of statements starts at the @code{.irpc} directive, and is
4331 terminated by an @code{.endr} directive. For each character in @var{value},
4332 @var{symbol} is set to the character, and the sequence of statements is
4333 assembled. If no @var{value} is listed, the sequence of statements is
4334 assembled once, with @var{symbol} set to the null string. To refer to
4335 @var{symbol} within the sequence of statements, use @var{\symbol}.
4337 For example, assembling
4345 is equivalent to assembling
4354 @section @code{.lcomm @var{symbol} , @var{length}}
4356 @cindex @code{lcomm} directive
4357 @cindex local common symbols
4358 @cindex symbols, local common
4359 Reserve @var{length} (an absolute expression) bytes for a local common
4360 denoted by @var{symbol}. The section and value of @var{symbol} are
4361 those of the new local common. The addresses are allocated in the bss
4362 section, so that at run-time the bytes start off zeroed. @var{Symbol}
4363 is not declared global (@pxref{Global,,@code{.global}}), so is normally
4364 not visible to @code{@value{LD}}.
4367 Some targets permit a third argument to be used with @code{.lcomm}. This
4368 argument specifies the desired alignment of the symbol in the bss section.
4372 The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
4373 @samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
4377 @section @code{.lflags}
4379 @cindex @code{lflags} directive (ignored)
4380 @command{@value{AS}} accepts this directive, for compatibility with other
4381 assemblers, but ignores it.
4383 @ifclear no-line-dir
4385 @section @code{.line @var{line-number}}
4387 @cindex @code{line} directive
4391 @section @code{.ln @var{line-number}}
4393 @cindex @code{ln} directive
4395 @cindex logical line number
4397 Change the logical line number. @var{line-number} must be an absolute
4398 expression. The next line has that logical line number. Therefore any other
4399 statements on the current line (after a statement separator character) are
4400 reported as on logical line number @var{line-number} @minus{} 1. One day
4401 @command{@value{AS}} will no longer support this directive: it is recognized only
4402 for compatibility with existing assembler programs.
4406 @emph{Warning:} In the AMD29K configuration of @value{AS}, this command is
4407 not available; use the synonym @code{.ln} in that context.
4412 @ifclear no-line-dir
4413 Even though this is a directive associated with the @code{a.out} or
4414 @code{b.out} object-code formats, @command{@value{AS}} still recognizes it
4415 when producing COFF output, and treats @samp{.line} as though it
4416 were the COFF @samp{.ln} @emph{if} it is found outside a
4417 @code{.def}/@code{.endef} pair.
4419 Inside a @code{.def}, @samp{.line} is, instead, one of the directives
4420 used by compilers to generate auxiliary symbol information for
4425 @section @code{.linkonce [@var{type}]}
4427 @cindex @code{linkonce} directive
4428 @cindex common sections
4429 Mark the current section so that the linker only includes a single copy of it.
4430 This may be used to include the same section in several different object files,
4431 but ensure that the linker will only include it once in the final output file.
4432 The @code{.linkonce} pseudo-op must be used for each instance of the section.
4433 Duplicate sections are detected based on the section name, so it should be
4436 This directive is only supported by a few object file formats; as of this
4437 writing, the only object file format which supports it is the Portable
4438 Executable format used on Windows NT.
4440 The @var{type} argument is optional. If specified, it must be one of the
4441 following strings. For example:
4445 Not all types may be supported on all object file formats.
4449 Silently discard duplicate sections. This is the default.
4452 Warn if there are duplicate sections, but still keep only one copy.
4455 Warn if any of the duplicates have different sizes.
4458 Warn if any of the duplicates do not have exactly the same contents.
4462 @section @code{.ln @var{line-number}}
4464 @cindex @code{ln} directive
4465 @ifclear no-line-dir
4466 @samp{.ln} is a synonym for @samp{.line}.
4469 Tell @command{@value{AS}} to change the logical line number. @var{line-number}
4470 must be an absolute expression. The next line has that logical
4471 line number, so any other statements on the current line (after a
4472 statement separator character @code{;}) are reported as on logical
4473 line number @var{line-number} @minus{} 1.
4476 This directive is accepted, but ignored, when @command{@value{AS}} is
4477 configured for @code{b.out}; its effect is only associated with COFF
4483 @section @code{.mri @var{val}}
4485 @cindex @code{mri} directive
4486 @cindex MRI mode, temporarily
4487 If @var{val} is non-zero, this tells @command{@value{AS}} to enter MRI mode. If
4488 @var{val} is zero, this tells @command{@value{AS}} to exit MRI mode. This change
4489 affects code assembled until the next @code{.mri} directive, or until the end
4490 of the file. @xref{M, MRI mode, MRI mode}.
4493 @section @code{.list}
4495 @cindex @code{list} directive
4496 @cindex listing control, turning on
4497 Control (in conjunction with the @code{.nolist} directive) whether or
4498 not assembly listings are generated. These two directives maintain an
4499 internal counter (which is zero initially). @code{.list} increments the
4500 counter, and @code{.nolist} decrements it. Assembly listings are
4501 generated whenever the counter is greater than zero.
4503 By default, listings are disabled. When you enable them (with the
4504 @samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
4505 the initial value of the listing counter is one.
4508 @section @code{.long @var{expressions}}
4510 @cindex @code{long} directive
4511 @code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}.
4514 @c no one seems to know what this is for or whether this description is
4515 @c what it really ought to do
4517 @section @code{.lsym @var{symbol}, @var{expression}}
4519 @cindex @code{lsym} directive
4520 @cindex symbol, not referenced in assembly
4521 @code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
4522 the hash table, ensuring it cannot be referenced by name during the
4523 rest of the assembly. This sets the attributes of the symbol to be
4524 the same as the expression value:
4526 @var{other} = @var{descriptor} = 0
4527 @var{type} = @r{(section of @var{expression})}
4528 @var{value} = @var{expression}
4531 The new symbol is not flagged as external.
4535 @section @code{.macro}
4538 The commands @code{.macro} and @code{.endm} allow you to define macros that
4539 generate assembly output. For example, this definition specifies a macro
4540 @code{sum} that puts a sequence of numbers into memory:
4543 .macro sum from=0, to=5
4552 With that definition, @samp{SUM 0,5} is equivalent to this assembly input:
4564 @item .macro @var{macname}
4565 @itemx .macro @var{macname} @var{macargs} @dots{}
4566 @cindex @code{macro} directive
4567 Begin the definition of a macro called @var{macname}. If your macro
4568 definition requires arguments, specify their names after the macro name,
4569 separated by commas or spaces. You can supply a default value for any
4570 macro argument by following the name with @samp{=@var{deflt}}. For
4571 example, these are all valid @code{.macro} statements:
4575 Begin the definition of a macro called @code{comm}, which takes no
4578 @item .macro plus1 p, p1
4579 @itemx .macro plus1 p p1
4580 Either statement begins the definition of a macro called @code{plus1},
4581 which takes two arguments; within the macro definition, write
4582 @samp{\p} or @samp{\p1} to evaluate the arguments.
4584 @item .macro reserve_str p1=0 p2
4585 Begin the definition of a macro called @code{reserve_str}, with two
4586 arguments. The first argument has a default value, but not the second.
4587 After the definition is complete, you can call the macro either as
4588 @samp{reserve_str @var{a},@var{b}} (with @samp{\p1} evaluating to
4589 @var{a} and @samp{\p2} evaluating to @var{b}), or as @samp{reserve_str
4590 ,@var{b}} (with @samp{\p1} evaluating as the default, in this case
4591 @samp{0}, and @samp{\p2} evaluating to @var{b}).
4594 When you call a macro, you can specify the argument values either by
4595 position, or by keyword. For example, @samp{sum 9,17} is equivalent to
4596 @samp{sum to=17, from=9}.
4599 @cindex @code{endm} directive
4600 Mark the end of a macro definition.
4603 @cindex @code{exitm} directive
4604 Exit early from the current macro definition.
4606 @cindex number of macros executed
4607 @cindex macros, count executed
4609 @command{@value{AS}} maintains a counter of how many macros it has
4610 executed in this pseudo-variable; you can copy that number to your
4611 output with @samp{\@@}, but @emph{only within a macro definition}.
4614 @item LOCAL @var{name} [ , @dots{} ]
4615 @emph{Warning: @code{LOCAL} is only available if you select ``alternate
4616 macro syntax'' with @samp{-a} or @samp{--alternate}.} @xref{Alternate,,
4617 Alternate macro syntax}.
4619 Generate a string replacement for each of the @var{name} arguments, and
4620 replace any instances of @var{name} in each macro expansion. The
4621 replacement string is unique in the assembly, and different for each
4622 separate macro expansion. @code{LOCAL} allows you to write macros that
4623 define symbols, without fear of conflict between separate macro expansions.
4628 @section @code{.nolist}
4630 @cindex @code{nolist} directive
4631 @cindex listing control, turning off
4632 Control (in conjunction with the @code{.list} directive) whether or
4633 not assembly listings are generated. These two directives maintain an
4634 internal counter (which is zero initially). @code{.list} increments the
4635 counter, and @code{.nolist} decrements it. Assembly listings are
4636 generated whenever the counter is greater than zero.
4639 @section @code{.octa @var{bignums}}
4641 @c FIXME: double size emitted for "octa" on i960, others? Or warn?
4642 @cindex @code{octa} directive
4643 @cindex integer, 16-byte
4644 @cindex sixteen byte integer
4645 This directive expects zero or more bignums, separated by commas. For each
4646 bignum, it emits a 16-byte integer.
4648 The term ``octa'' comes from contexts in which a ``word'' is two bytes;
4649 hence @emph{octa}-word for 16 bytes.
4652 @section @code{.org @var{new-lc} , @var{fill}}
4654 @cindex @code{org} directive
4655 @cindex location counter, advancing
4656 @cindex advancing location counter
4657 @cindex current address, advancing
4658 Advance the location counter of the current section to
4659 @var{new-lc}. @var{new-lc} is either an absolute expression or an
4660 expression with the same section as the current subsection. That is,
4661 you can't use @code{.org} to cross sections: if @var{new-lc} has the
4662 wrong section, the @code{.org} directive is ignored. To be compatible
4663 with former assemblers, if the section of @var{new-lc} is absolute,
4664 @command{@value{AS}} issues a warning, then pretends the section of @var{new-lc}
4665 is the same as the current subsection.
4667 @code{.org} may only increase the location counter, or leave it
4668 unchanged; you cannot use @code{.org} to move the location counter
4671 @c double negative used below "not undefined" because this is a specific
4672 @c reference to "undefined" (as SEG_UNKNOWN is called in this manual)
4673 @c section. doc@cygnus.com 18feb91
4674 Because @command{@value{AS}} tries to assemble programs in one pass, @var{new-lc}
4675 may not be undefined. If you really detest this restriction we eagerly await
4676 a chance to share your improved assembler.
4678 Beware that the origin is relative to the start of the section, not
4679 to the start of the subsection. This is compatible with other
4680 people's assemblers.
4682 When the location counter (of the current subsection) is advanced, the
4683 intervening bytes are filled with @var{fill} which should be an
4684 absolute expression. If the comma and @var{fill} are omitted,
4685 @var{fill} defaults to zero.
4688 @section @code{.p2align[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
4690 @cindex padding the location counter given a power of two
4691 @cindex @code{p2align} directive
4692 Pad the location counter (in the current subsection) to a particular
4693 storage boundary. The first expression (which must be absolute) is the
4694 number of low-order zero bits the location counter must have after
4695 advancement. For example @samp{.p2align 3} advances the location
4696 counter until it a multiple of 8. If the location counter is already a
4697 multiple of 8, no change is needed.
4699 The second expression (also absolute) gives the fill value to be stored in the
4700 padding bytes. It (and the comma) may be omitted. If it is omitted, the
4701 padding bytes are normally zero. However, on some systems, if the section is
4702 marked as containing code and the fill value is omitted, the space is filled
4703 with no-op instructions.
4705 The third expression is also absolute, and is also optional. If it is present,
4706 it is the maximum number of bytes that should be skipped by this alignment
4707 directive. If doing the alignment would require skipping more bytes than the
4708 specified maximum, then the alignment is not done at all. You can omit the
4709 fill value (the second argument) entirely by simply using two commas after the
4710 required alignment; this can be useful if you want the alignment to be filled
4711 with no-op instructions when appropriate.
4713 @cindex @code{p2alignw} directive
4714 @cindex @code{p2alignl} directive
4715 The @code{.p2alignw} and @code{.p2alignl} directives are variants of the
4716 @code{.p2align} directive. The @code{.p2alignw} directive treats the fill
4717 pattern as a two byte word value. The @code{.p2alignl} directives treats the
4718 fill pattern as a four byte longword value. For example, @code{.p2alignw
4719 2,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
4720 filled in with the value 0x368d (the exact placement of the bytes depends upon
4721 the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
4726 @section @code{.previous}
4728 @cindex @code{.previous} directive
4729 @cindex Section Stack
4730 This is one of the ELF section stack manipulation directives. The others are
4731 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4732 @code{.pushsection} (@pxref{PushSection}), and @code{.popsection}
4733 (@pxref{PopSection}).
4735 This directive swaps the current section (and subsection) with most recently
4736 referenced section (and subsection) prior to this one. Multiple
4737 @code{.previous} directives in a row will flip between two sections (and their
4740 In terms of the section stack, this directive swaps the current section with
4741 the top section on the section stack.
4746 @section @code{.popsection}
4748 @cindex @code{.popsection} directive
4749 @cindex Section Stack
4750 This is one of the ELF section stack manipulation directives. The others are
4751 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4752 @code{.pushsection} (@pxref{PushSection}), and @code{.previous}
4755 This directive replaces the current section (and subsection) with the top
4756 section (and subsection) on the section stack. This section is popped off the
4761 @section @code{.print @var{string}}
4763 @cindex @code{print} directive
4764 @command{@value{AS}} will print @var{string} on the standard output during
4765 assembly. You must put @var{string} in double quotes.
4769 @section @code{.protected @var{names}}
4771 @cindex @code{.protected} directive
4773 This one of the ELF visibility directives. The other two are
4774 @code{.hidden} (@pxref{Hidden}) and @code{.internal} (@pxref{Internal}).
4776 This directive overrides the named symbols default visibility (which is set by
4777 their binding: local, global or weak). The directive sets the visibility to
4778 @code{protected} which means that any references to the symbols from within the
4779 components that defines them must be resolved to the definition in that
4780 component, even if a definition in another component would normally preempt
4785 @section @code{.psize @var{lines} , @var{columns}}
4787 @cindex @code{psize} directive
4788 @cindex listing control: paper size
4789 @cindex paper size, for listings
4790 Use this directive to declare the number of lines---and, optionally, the
4791 number of columns---to use for each page, when generating listings.
4793 If you do not use @code{.psize}, listings use a default line-count
4794 of 60. You may omit the comma and @var{columns} specification; the
4795 default width is 200 columns.
4797 @command{@value{AS}} generates formfeeds whenever the specified number of
4798 lines is exceeded (or whenever you explicitly request one, using
4801 If you specify @var{lines} as @code{0}, no formfeeds are generated save
4802 those explicitly specified with @code{.eject}.
4805 @section @code{.purgem @var{name}}
4807 @cindex @code{purgem} directive
4808 Undefine the macro @var{name}, so that later uses of the string will not be
4809 expanded. @xref{Macro}.
4813 @section @code{.pushsection @var{name} , @var{subsection}}
4815 @cindex @code{.pushsection} directive
4816 @cindex Section Stack
4817 This is one of the ELF section stack manipulation directives. The others are
4818 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4819 @code{.popsection} (@pxref{PopSection}), and @code{.previous}
4822 This directive is a synonym for @code{.section}. It pushes the current section
4823 (and subsection) onto the top of the section stack, and then replaces the
4824 current section and subsection with @code{name} and @code{subsection}.
4828 @section @code{.quad @var{bignums}}
4830 @cindex @code{quad} directive
4831 @code{.quad} expects zero or more bignums, separated by commas. For
4832 each bignum, it emits
4834 an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a
4835 warning message; and just takes the lowest order 8 bytes of the bignum.
4836 @cindex eight-byte integer
4837 @cindex integer, 8-byte
4839 The term ``quad'' comes from contexts in which a ``word'' is two bytes;
4840 hence @emph{quad}-word for 8 bytes.
4843 a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
4844 warning message; and just takes the lowest order 16 bytes of the bignum.
4845 @cindex sixteen-byte integer
4846 @cindex integer, 16-byte
4850 @section @code{.rept @var{count}}
4852 @cindex @code{rept} directive
4853 Repeat the sequence of lines between the @code{.rept} directive and the next
4854 @code{.endr} directive @var{count} times.
4856 For example, assembling
4864 is equivalent to assembling
4873 @section @code{.sbttl "@var{subheading}"}
4875 @cindex @code{sbttl} directive
4876 @cindex subtitles for listings
4877 @cindex listing control: subtitle
4878 Use @var{subheading} as the title (third line, immediately after the
4879 title line) when generating assembly listings.
4881 This directive affects subsequent pages, as well as the current page if
4882 it appears within ten lines of the top of a page.
4886 @section @code{.scl @var{class}}
4888 @cindex @code{scl} directive
4889 @cindex symbol storage class (COFF)
4890 @cindex COFF symbol storage class
4891 Set the storage-class value for a symbol. This directive may only be
4892 used inside a @code{.def}/@code{.endef} pair. Storage class may flag
4893 whether a symbol is static or external, or it may record further
4894 symbolic debugging information.
4897 The @samp{.scl} directive is primarily associated with COFF output; when
4898 configured to generate @code{b.out} output format, @command{@value{AS}}
4899 accepts this directive but ignores it.
4904 @section @code{.section @var{name}} (COFF version)
4906 @cindex @code{section} directive
4907 @cindex named section
4908 Use the @code{.section} directive to assemble the following code into a section
4911 This directive is only supported for targets that actually support arbitrarily
4912 named sections; on @code{a.out} targets, for example, it is not accepted, even
4913 with a standard @code{a.out} section name.
4915 For COFF targets, the @code{.section} directive is used in one of the following
4919 .section @var{name}[, "@var{flags}"]
4920 .section @var{name}[, @var{subsegment}]
4923 If the optional argument is quoted, it is taken as flags to use for the
4924 section. Each flag is a single character. The following flags are recognized:
4927 bss section (uninitialized data)
4929 section is not loaded
4939 shared section (meaningful for PE targets)
4942 If no flags are specified, the default flags depend upon the section name. If
4943 the section name is not recognized, the default will be for the section to be
4944 loaded and writable. Note the @code{n} and @code{w} flags remove attributes
4945 from the section, rather than adding them, so if they are used on their own it
4946 will be as if no flags had been specified at all.
4948 If the optional argument to the @code{.section} directive is not quoted, it is
4949 taken as a subsegment number (@pxref{Sub-Sections}).
4952 @section @code{.section @var{name}} (ELF version)
4954 @cindex @code{section} directive
4955 @cindex named section
4957 @cindex Section Stack
4958 This is one of the ELF section stack manipulation directives. The others are
4959 @code{.subsection} (@pxref{SubSection}), @code{.pushsection}
4960 (@pxref{PushSection}), @code{.popsection} (@pxref{PopSection}), and
4961 @code{.previous} (@pxref{Previous}).
4964 For ELF targets, the @code{.section} directive is used like this:
4967 .section @var{name} [, "@var{flags}"[, @@@var{type}[, @@@var{entsize}]]]
4970 The optional @var{flags} argument is a quoted string which may contain any
4971 combination of the following characters:
4974 section is allocatable
4978 section is executable
4980 section is mergeable
4982 section contains zero terminated strings
4985 The optional @var{type} argument may contain one of the following constants:
4988 section contains data
4990 section does not contain data (i.e., section only occupies space)
4993 If @var{flags} contains @code{M} flag, @var{type} argument must be specified
4994 as well as @var{entsize} argument. Sections with @code{M} flag but not
4995 @code{S} flag must contain fixed size constants, each @var{entsize} octets
4996 long. Sections with both @code{M} and @code{S} must contain zero terminated
4997 strings where each character is @var{entsize} bytes long. The linker may remove
4998 duplicates within sections with the same name, same entity size and same flags.
5000 If no flags are specified, the default flags depend upon the section name. If
5001 the section name is not recognized, the default will be for the section to have
5002 none of the above flags: it will not be allocated in memory, nor writable, nor
5003 executable. The section will contain data.
5005 For ELF targets, the assembler supports another type of @code{.section}
5006 directive for compatibility with the Solaris assembler:
5009 .section "@var{name}"[, @var{flags}...]
5012 Note that the section name is quoted. There may be a sequence of comma
5016 section is allocatable
5020 section is executable
5023 This directive replaces the current section and subsection. The replaced
5024 section and subsection are pushed onto the section stack. See the contents of
5025 the gas testsuite directory @code{gas/testsuite/gas/elf} for some examples of
5026 how this directive and the other section stack directives work.
5029 @section @code{.set @var{symbol}, @var{expression}}
5031 @cindex @code{set} directive
5032 @cindex symbol value, setting
5033 Set the value of @var{symbol} to @var{expression}. This
5034 changes @var{symbol}'s value and type to conform to
5035 @var{expression}. If @var{symbol} was flagged as external, it remains
5036 flagged (@pxref{Symbol Attributes}).
5038 You may @code{.set} a symbol many times in the same assembly.
5040 If you @code{.set} a global symbol, the value stored in the object
5041 file is the last value stored into it.
5044 The syntax for @code{set} on the HPPA is
5045 @samp{@var{symbol} .set @var{expression}}.
5049 @section @code{.short @var{expressions}}
5051 @cindex @code{short} directive
5053 @code{.short} is normally the same as @samp{.word}.
5054 @xref{Word,,@code{.word}}.
5056 In some configurations, however, @code{.short} and @code{.word} generate
5057 numbers of different lengths; @pxref{Machine Dependencies}.
5061 @code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
5064 This expects zero or more @var{expressions}, and emits
5065 a 16 bit number for each.
5070 @section @code{.single @var{flonums}}
5072 @cindex @code{single} directive
5073 @cindex floating point numbers (single)
5074 This directive assembles zero or more flonums, separated by commas. It
5075 has the same effect as @code{.float}.
5077 The exact kind of floating point numbers emitted depends on how
5078 @command{@value{AS}} is configured. @xref{Machine Dependencies}.
5082 On the @value{TARGET} family, @code{.single} emits 32-bit floating point
5083 numbers in @sc{ieee} format.
5088 @section @code{.size} (COFF version)
5090 @cindex @code{size} directive
5091 This directive is generated by compilers to include auxiliary debugging
5092 information in the symbol table. It is only permitted inside
5093 @code{.def}/@code{.endef} pairs.
5096 @samp{.size} is only meaningful when generating COFF format output; when
5097 @command{@value{AS}} is generating @code{b.out}, it accepts this directive but
5101 @section @code{.size @var{name} , @var{expression}} (ELF version)
5102 @cindex @code{size} directive
5104 This directive is used to set the size associated with a symbol @var{name}.
5105 The size in bytes is computed from @var{expression} which can make use of label
5106 arithmetic. This directive is typically used to set the size of function
5110 @section @code{.sleb128 @var{expressions}}
5112 @cindex @code{sleb128} directive
5113 @var{sleb128} stands for ``signed little endian base 128.'' This is a
5114 compact, variable length representation of numbers used by the DWARF
5115 symbolic debugging format. @xref{Uleb128,@code{.uleb128}}.
5117 @ifclear no-space-dir
5119 @section @code{.skip @var{size} , @var{fill}}
5121 @cindex @code{skip} directive
5122 @cindex filling memory
5123 This directive emits @var{size} bytes, each of value @var{fill}. Both
5124 @var{size} and @var{fill} are absolute expressions. If the comma and
5125 @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same as
5129 @section @code{.space @var{size} , @var{fill}}
5131 @cindex @code{space} directive
5132 @cindex filling memory
5133 This directive emits @var{size} bytes, each of value @var{fill}. Both
5134 @var{size} and @var{fill} are absolute expressions. If the comma
5135 and @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same
5140 @emph{Warning:} @code{.space} has a completely different meaning for HPPA
5141 targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
5142 Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the
5143 @code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives},
5152 @section @code{.space}
5153 @cindex @code{space} directive
5155 On the AMD 29K, this directive is ignored; it is accepted for
5156 compatibility with other AMD 29K assemblers.
5159 @emph{Warning:} In most versions of the @sc{gnu} assembler, the directive
5160 @code{.space} has the effect of @code{.block} @xref{Machine Dependencies}.
5166 @section @code{.stabd, .stabn, .stabs}
5168 @cindex symbolic debuggers, information for
5169 @cindex @code{stab@var{x}} directives
5170 There are three directives that begin @samp{.stab}.
5171 All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
5172 The symbols are not entered in the @command{@value{AS}} hash table: they
5173 cannot be referenced elsewhere in the source file.
5174 Up to five fields are required:
5178 This is the symbol's name. It may contain any character except
5179 @samp{\000}, so is more general than ordinary symbol names. Some
5180 debuggers used to code arbitrarily complex structures into symbol names
5184 An absolute expression. The symbol's type is set to the low 8 bits of
5185 this expression. Any bit pattern is permitted, but @code{@value{LD}}
5186 and debuggers choke on silly bit patterns.
5189 An absolute expression. The symbol's ``other'' attribute is set to the
5190 low 8 bits of this expression.
5193 An absolute expression. The symbol's descriptor is set to the low 16
5194 bits of this expression.
5197 An absolute expression which becomes the symbol's value.
5200 If a warning is detected while reading a @code{.stabd}, @code{.stabn},
5201 or @code{.stabs} statement, the symbol has probably already been created;
5202 you get a half-formed symbol in your object file. This is
5203 compatible with earlier assemblers!
5206 @cindex @code{stabd} directive
5207 @item .stabd @var{type} , @var{other} , @var{desc}
5209 The ``name'' of the symbol generated is not even an empty string.
5210 It is a null pointer, for compatibility. Older assemblers used a
5211 null pointer so they didn't waste space in object files with empty
5214 The symbol's value is set to the location counter,
5215 relocatably. When your program is linked, the value of this symbol
5216 is the address of the location counter when the @code{.stabd} was
5219 @cindex @code{stabn} directive
5220 @item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
5221 The name of the symbol is set to the empty string @code{""}.
5223 @cindex @code{stabs} directive
5224 @item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
5225 All five fields are specified.
5231 @section @code{.string} "@var{str}"
5233 @cindex string, copying to object file
5234 @cindex @code{string} directive
5236 Copy the characters in @var{str} to the object file. You may specify more than
5237 one string to copy, separated by commas. Unless otherwise specified for a
5238 particular machine, the assembler marks the end of each string with a 0 byte.
5239 You can use any of the escape sequences described in @ref{Strings,,Strings}.
5242 @section @code{.struct @var{expression}}
5244 @cindex @code{struct} directive
5245 Switch to the absolute section, and set the section offset to @var{expression},
5246 which must be an absolute expression. You might use this as follows:
5255 This would define the symbol @code{field1} to have the value 0, the symbol
5256 @code{field2} to have the value 4, and the symbol @code{field3} to have the
5257 value 8. Assembly would be left in the absolute section, and you would need to
5258 use a @code{.section} directive of some sort to change to some other section
5259 before further assembly.
5263 @section @code{.subsection @var{name}}
5265 @cindex @code{.subsection} directive
5266 @cindex Section Stack
5267 This is one of the ELF section stack manipulation directives. The others are
5268 @code{.section} (@pxref{Section}), @code{.pushsection} (@pxref{PushSection}),
5269 @code{.popsection} (@pxref{PopSection}), and @code{.previous}
5272 This directive replaces the current subsection with @code{name}. The current
5273 section is not changed. The replaced subsection is put onto the section stack
5274 in place of the then current top of stack subsection.
5279 @section @code{.symver}
5280 @cindex @code{symver} directive
5281 @cindex symbol versioning
5282 @cindex versions of symbols
5283 Use the @code{.symver} directive to bind symbols to specific version nodes
5284 within a source file. This is only supported on ELF platforms, and is
5285 typically used when assembling files to be linked into a shared library.
5286 There are cases where it may make sense to use this in objects to be bound
5287 into an application itself so as to override a versioned symbol from a
5290 For ELF targets, the @code{.symver} directive can be used like this:
5292 .symver @var{name}, @var{name2@@nodename}
5294 If the symbol @var{name} is defined within the file
5295 being assembled, the @code{.symver} directive effectively creates a symbol
5296 alias with the name @var{name2@@nodename}, and in fact the main reason that we
5297 just don't try and create a regular alias is that the @var{@@} character isn't
5298 permitted in symbol names. The @var{name2} part of the name is the actual name
5299 of the symbol by which it will be externally referenced. The name @var{name}
5300 itself is merely a name of convenience that is used so that it is possible to
5301 have definitions for multiple versions of a function within a single source
5302 file, and so that the compiler can unambiguously know which version of a
5303 function is being mentioned. The @var{nodename} portion of the alias should be
5304 the name of a node specified in the version script supplied to the linker when
5305 building a shared library. If you are attempting to override a versioned
5306 symbol from a shared library, then @var{nodename} should correspond to the
5307 nodename of the symbol you are trying to override.
5309 If the symbol @var{name} is not defined within the file being assembled, all
5310 references to @var{name} will be changed to @var{name2@@nodename}. If no
5311 reference to @var{name} is made, @var{name2@@nodename} will be removed from the
5314 Another usage of the @code{.symver} directive is:
5316 .symver @var{name}, @var{name2@@@@nodename}
5318 In this case, the symbol @var{name} must exist and be defined within
5319 the file being assembled. It is similar to @var{name2@@nodename}. The
5320 difference is @var{name2@@@@nodename} will also be used to resolve
5321 references to @var{name2} by the linker.
5323 The third usage of the @code{.symver} directive is:
5325 .symver @var{name}, @var{name2@@@@@@nodename}
5327 When @var{name} is not defined within the
5328 file being assembled, it is treated as @var{name2@@nodename}. When
5329 @var{name} is defined within the file being assembled, the symbol
5330 name, @var{name}, will be changed to @var{name2@@@@nodename}.
5335 @section @code{.tag @var{structname}}
5337 @cindex COFF structure debugging
5338 @cindex structure debugging, COFF
5339 @cindex @code{tag} directive
5340 This directive is generated by compilers to include auxiliary debugging
5341 information in the symbol table. It is only permitted inside
5342 @code{.def}/@code{.endef} pairs. Tags are used to link structure
5343 definitions in the symbol table with instances of those structures.
5346 @samp{.tag} is only used when generating COFF format output; when
5347 @command{@value{AS}} is generating @code{b.out}, it accepts this directive but
5353 @section @code{.text @var{subsection}}
5355 @cindex @code{text} directive
5356 Tells @command{@value{AS}} to assemble the following statements onto the end of
5357 the text subsection numbered @var{subsection}, which is an absolute
5358 expression. If @var{subsection} is omitted, subsection number zero
5362 @section @code{.title "@var{heading}"}
5364 @cindex @code{title} directive
5365 @cindex listing control: title line
5366 Use @var{heading} as the title (second line, immediately after the
5367 source file name and pagenumber) when generating assembly listings.
5369 This directive affects subsequent pages, as well as the current page if
5370 it appears within ten lines of the top of a page.
5373 @section @code{.type @var{int}} (COFF version)
5375 @cindex COFF symbol type
5376 @cindex symbol type, COFF
5377 @cindex @code{type} directive
5378 This directive, permitted only within @code{.def}/@code{.endef} pairs,
5379 records the integer @var{int} as the type attribute of a symbol table entry.
5382 @samp{.type} is associated only with COFF format output; when
5383 @command{@value{AS}} is configured for @code{b.out} output, it accepts this
5384 directive but ignores it.
5387 @section @code{.type @var{name} , @var{type description}} (ELF version)
5389 @cindex ELF symbol type
5390 @cindex symbol type, ELF
5391 @cindex @code{type} directive
5392 This directive is used to set the type of symbol @var{name} to be either a
5393 function symbol or an object symbol. There are five different syntaxes
5394 supported for the @var{type description} field, in order to provide
5395 compatibility with various other assemblers. The syntaxes supported are:
5398 .type <name>,#function
5399 .type <name>,#object
5401 .type <name>,@@function
5402 .type <name>,@@object
5404 .type <name>,%function
5405 .type <name>,%object
5407 .type <name>,"function"
5408 .type <name>,"object"
5410 .type <name> STT_FUNCTION
5411 .type <name> STT_OBJECT
5415 @section @code{.uleb128 @var{expressions}}
5417 @cindex @code{uleb128} directive
5418 @var{uleb128} stands for ``unsigned little endian base 128.'' This is a
5419 compact, variable length representation of numbers used by the DWARF
5420 symbolic debugging format. @xref{Sleb128,@code{.sleb128}}.
5424 @section @code{.val @var{addr}}
5426 @cindex @code{val} directive
5427 @cindex COFF value attribute
5428 @cindex value attribute, COFF
5429 This directive, permitted only within @code{.def}/@code{.endef} pairs,
5430 records the address @var{addr} as the value attribute of a symbol table
5434 @samp{.val} is used only for COFF output; when @command{@value{AS}} is
5435 configured for @code{b.out}, it accepts this directive but ignores it.
5441 @section @code{.version "@var{string}"}
5443 @cindex @code{.version}
5444 This directive creates a @code{.note} section and places into it an ELF
5445 formatted note of type NT_VERSION. The note's name is set to @code{string}.
5450 @section @code{.vtable_entry @var{table}, @var{offset}}
5452 @cindex @code{.vtable_entry}
5453 This directive finds or creates a symbol @code{table} and creates a
5454 @code{VTABLE_ENTRY} relocation for it with an addend of @code{offset}.
5457 @section @code{.vtable_inherit @var{child}, @var{parent}}
5459 @cindex @code{.vtable_inherit}
5460 This directive finds the symbol @code{child} and finds or creates the symbol
5461 @code{parent} and then creates a @code{VTABLE_INHERIT} relocation for the
5462 parent whose addend is the value of the child symbol. As a special case the
5463 parent name of @code{0} is treated as refering the @code{*ABS*} section.
5468 @section @code{.weak @var{names}}
5470 @cindex @code{.weak}
5471 This directive sets the weak attribute on the comma separated list of symbol
5472 @code{names}. If the symbols do not already exist, they will be created.
5476 @section @code{.word @var{expressions}}
5478 @cindex @code{word} directive
5479 This directive expects zero or more @var{expressions}, of any section,
5480 separated by commas.
5483 For each expression, @command{@value{AS}} emits a 32-bit number.
5486 For each expression, @command{@value{AS}} emits a 16-bit number.
5491 The size of the number emitted, and its byte order,
5492 depend on what target computer the assembly is for.
5495 @c on amd29k, i960, sparc the "special treatment to support compilers" doesn't
5496 @c happen---32-bit addressability, period; no long/short jumps.
5497 @ifset DIFF-TBL-KLUGE
5498 @cindex difference tables altered
5499 @cindex altered difference tables
5501 @emph{Warning: Special Treatment to support Compilers}
5505 Machines with a 32-bit address space, but that do less than 32-bit
5506 addressing, require the following special treatment. If the machine of
5507 interest to you does 32-bit addressing (or doesn't require it;
5508 @pxref{Machine Dependencies}), you can ignore this issue.
5511 In order to assemble compiler output into something that works,
5512 @command{@value{AS}} occasionally does strange things to @samp{.word} directives.
5513 Directives of the form @samp{.word sym1-sym2} are often emitted by
5514 compilers as part of jump tables. Therefore, when @command{@value{AS}} assembles a
5515 directive of the form @samp{.word sym1-sym2}, and the difference between
5516 @code{sym1} and @code{sym2} does not fit in 16 bits, @command{@value{AS}}
5517 creates a @dfn{secondary jump table}, immediately before the next label.
5518 This secondary jump table is preceded by a short-jump to the
5519 first byte after the secondary table. This short-jump prevents the flow
5520 of control from accidentally falling into the new table. Inside the
5521 table is a long-jump to @code{sym2}. The original @samp{.word}
5522 contains @code{sym1} minus the address of the long-jump to
5525 If there were several occurrences of @samp{.word sym1-sym2} before the
5526 secondary jump table, all of them are adjusted. If there was a
5527 @samp{.word sym3-sym4}, that also did not fit in sixteen bits, a
5528 long-jump to @code{sym4} is included in the secondary jump table,
5529 and the @code{.word} directives are adjusted to contain @code{sym3}
5530 minus the address of the long-jump to @code{sym4}; and so on, for as many
5531 entries in the original jump table as necessary.
5534 @emph{This feature may be disabled by compiling @command{@value{AS}} with the
5535 @samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse
5536 assembly language programmers.
5539 @c end DIFF-TBL-KLUGE
5542 @section Deprecated Directives
5544 @cindex deprecated directives
5545 @cindex obsolescent directives
5546 One day these directives won't work.
5547 They are included for compatibility with older assemblers.
5554 @node Machine Dependencies
5555 @chapter Machine Dependent Features
5557 @cindex machine dependencies
5558 The machine instruction sets are (almost by definition) different on
5559 each machine where @command{@value{AS}} runs. Floating point representations
5560 vary as well, and @command{@value{AS}} often supports a few additional
5561 directives or command-line options for compatibility with other
5562 assemblers on a particular platform. Finally, some versions of
5563 @command{@value{AS}} support special pseudo-instructions for branch
5566 This chapter discusses most of these differences, though it does not
5567 include details on any machine's instruction set. For details on that
5568 subject, see the hardware manufacturer's manual.
5572 * AMD29K-Dependent:: AMD 29K Dependent Features
5575 * ARC-Dependent:: ARC Dependent Features
5578 * ARM-Dependent:: ARM Dependent Features
5581 * D10V-Dependent:: D10V Dependent Features
5584 * D30V-Dependent:: D30V Dependent Features
5587 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
5590 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
5593 * HPPA-Dependent:: HPPA Dependent Features
5596 * ESA/390-Dependent:: IBM ESA/390 Dependent Features
5599 * i386-Dependent:: Intel 80386 and AMD x86-64 Dependent Features
5602 * i860-Dependent:: Intel 80860 Dependent Features
5605 * i960-Dependent:: Intel 80960 Dependent Features
5608 * M32R-Dependent:: M32R Dependent Features
5611 * M68K-Dependent:: M680x0 Dependent Features
5614 * M68HC11-Dependent:: M68HC11 and 68HC12 Dependent Features
5617 * M88K-Dependent:: M880x0 Dependent Features
5620 * MIPS-Dependent:: MIPS Dependent Features
5623 * MMIX-Dependent:: MMIX Dependent Features
5626 * SH-Dependent:: Hitachi SH Dependent Features
5629 * PDP-11-Dependent:: PDP-11 Dependent Features
5632 * PJ-Dependent:: picoJava Dependent Features
5635 * PPC-Dependent:: PowerPC Dependent Features
5638 * Sparc-Dependent:: SPARC Dependent Features
5641 * TIC54X-Dependent:: TI TMS320C54x Dependent Features
5644 * V850-Dependent:: V850 Dependent Features
5647 * Z8000-Dependent:: Z8000 Dependent Features
5650 * Vax-Dependent:: VAX Dependent Features
5657 @c The following major nodes are *sections* in the GENERIC version, *chapters*
5658 @c in single-cpu versions. This is mainly achieved by @lowersections. There is a
5659 @c peculiarity: to preserve cross-references, there must be a node called
5660 @c "Machine Dependencies". Hence the conditional nodenames in each
5661 @c major node below. Node defaulting in makeinfo requires adjacency of
5662 @c node and sectioning commands; hence the repetition of @chapter BLAH
5663 @c in both conditional blocks.
5670 @include c-a29k.texi
5679 @node Machine Dependencies
5680 @chapter Machine Dependent Features
5682 The machine instruction sets are different on each Hitachi chip family,
5683 and there are also some syntax differences among the families. This
5684 chapter describes the specific @command{@value{AS}} features for each
5688 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
5689 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
5690 * SH-Dependent:: Hitachi SH Dependent Features
5697 @include c-d10v.texi
5701 @include c-d30v.texi
5705 @include c-h8300.texi
5709 @include c-h8500.texi
5713 @include c-hppa.texi
5717 @include c-i370.texi
5721 @include c-i386.texi
5725 @include c-i860.texi
5729 @include c-i960.texi
5733 @include c-m32r.texi
5737 @include c-m68k.texi
5741 @include c-m68hc11.texi
5745 @include c-m88k.texi
5749 @include c-mips.texi
5753 @include c-mmix.texi
5757 @include c-ns32k.texi
5761 @include c-pdp11.texi
5777 @include c-sparc.texi
5781 @include c-tic54x.texi
5793 @include c-v850.texi
5797 @c reverse effect of @down at top of generic Machine-Dep chapter
5801 @node Reporting Bugs
5802 @chapter Reporting Bugs
5803 @cindex bugs in assembler
5804 @cindex reporting bugs in assembler
5806 Your bug reports play an essential role in making @command{@value{AS}} reliable.
5808 Reporting a bug may help you by bringing a solution to your problem, or it may
5809 not. But in any case the principal function of a bug report is to help the
5810 entire community by making the next version of @command{@value{AS}} work better.
5811 Bug reports are your contribution to the maintenance of @command{@value{AS}}.
5813 In order for a bug report to serve its purpose, you must include the
5814 information that enables us to fix the bug.
5817 * Bug Criteria:: Have you found a bug?
5818 * Bug Reporting:: How to report bugs
5822 @section Have you found a bug?
5823 @cindex bug criteria
5825 If you are not sure whether you have found a bug, here are some guidelines:
5828 @cindex fatal signal
5829 @cindex assembler crash
5830 @cindex crash of assembler
5832 If the assembler gets a fatal signal, for any input whatever, that is a
5833 @command{@value{AS}} bug. Reliable assemblers never crash.
5835 @cindex error on valid input
5837 If @command{@value{AS}} produces an error message for valid input, that is a bug.
5839 @cindex invalid input
5841 If @command{@value{AS}} does not produce an error message for invalid input, that
5842 is a bug. However, you should note that your idea of ``invalid input'' might
5843 be our idea of ``an extension'' or ``support for traditional practice''.
5846 If you are an experienced user of assemblers, your suggestions for improvement
5847 of @command{@value{AS}} are welcome in any case.
5851 @section How to report bugs
5853 @cindex assembler bugs, reporting
5855 A number of companies and individuals offer support for @sc{gnu} products. If
5856 you obtained @command{@value{AS}} from a support organization, we recommend you
5857 contact that organization first.
5859 You can find contact information for many support companies and
5860 individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
5863 In any event, we also recommend that you send bug reports for @command{@value{AS}}
5864 to @samp{bug-binutils@@gnu.org}.
5866 The fundamental principle of reporting bugs usefully is this:
5867 @strong{report all the facts}. If you are not sure whether to state a
5868 fact or leave it out, state it!
5870 Often people omit facts because they think they know what causes the problem
5871 and assume that some details do not matter. Thus, you might assume that the
5872 name of a symbol you use in an example does not matter. Well, probably it does
5873 not, but one cannot be sure. Perhaps the bug is a stray memory reference which
5874 happens to fetch from the location where that name is stored in memory;
5875 perhaps, if the name were different, the contents of that location would fool
5876 the assembler into doing the right thing despite the bug. Play it safe and
5877 give a specific, complete example. That is the easiest thing for you to do,
5878 and the most helpful.
5880 Keep in mind that the purpose of a bug report is to enable us to fix the bug if
5881 it is new to us. Therefore, always write your bug reports on the assumption
5882 that the bug has not been reported previously.
5884 Sometimes people give a few sketchy facts and ask, ``Does this ring a
5885 bell?'' Those bug reports are useless, and we urge everyone to
5886 @emph{refuse to respond to them} except to chide the sender to report
5889 To enable us to fix the bug, you should include all these things:
5893 The version of @command{@value{AS}}. @command{@value{AS}} announces it if you start
5894 it with the @samp{--version} argument.
5896 Without this, we will not know whether there is any point in looking for
5897 the bug in the current version of @command{@value{AS}}.
5900 Any patches you may have applied to the @command{@value{AS}} source.
5903 The type of machine you are using, and the operating system name and
5907 What compiler (and its version) was used to compile @command{@value{AS}}---e.g.
5911 The command arguments you gave the assembler to assemble your example and
5912 observe the bug. To guarantee you will not omit something important, list them
5913 all. A copy of the Makefile (or the output from make) is sufficient.
5915 If we were to try to guess the arguments, we would probably guess wrong
5916 and then we might not encounter the bug.
5919 A complete input file that will reproduce the bug. If the bug is observed when
5920 the assembler is invoked via a compiler, send the assembler source, not the
5921 high level language source. Most compilers will produce the assembler source
5922 when run with the @samp{-S} option. If you are using @code{@value{GCC}}, use
5923 the options @samp{-v --save-temps}; this will save the assembler source in a
5924 file with an extension of @file{.s}, and also show you exactly how
5925 @command{@value{AS}} is being run.
5928 A description of what behavior you observe that you believe is
5929 incorrect. For example, ``It gets a fatal signal.''
5931 Of course, if the bug is that @command{@value{AS}} gets a fatal signal, then we
5932 will certainly notice it. But if the bug is incorrect output, we might not
5933 notice unless it is glaringly wrong. You might as well not give us a chance to
5936 Even if the problem you experience is a fatal signal, you should still say so
5937 explicitly. Suppose something strange is going on, such as, your copy of
5938 @command{@value{AS}} is out of synch, or you have encountered a bug in the C
5939 library on your system. (This has happened!) Your copy might crash and ours
5940 would not. If you told us to expect a crash, then when ours fails to crash, we
5941 would know that the bug was not happening for us. If you had not told us to
5942 expect a crash, then we would not be able to draw any conclusion from our
5946 If you wish to suggest changes to the @command{@value{AS}} source, send us context
5947 diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p}
5948 option. Always send diffs from the old file to the new file. If you even
5949 discuss something in the @command{@value{AS}} source, refer to it by context, not
5952 The line numbers in our development sources will not match those in your
5953 sources. Your line numbers would convey no useful information to us.
5956 Here are some things that are not necessary:
5960 A description of the envelope of the bug.
5962 Often people who encounter a bug spend a lot of time investigating
5963 which changes to the input file will make the bug go away and which
5964 changes will not affect it.
5966 This is often time consuming and not very useful, because the way we
5967 will find the bug is by running a single example under the debugger
5968 with breakpoints, not by pure deduction from a series of examples.
5969 We recommend that you save your time for something else.
5971 Of course, if you can find a simpler example to report @emph{instead}
5972 of the original one, that is a convenience for us. Errors in the
5973 output will be easier to spot, running under the debugger will take
5974 less time, and so on.
5976 However, simplification is not vital; if you do not want to do this,
5977 report the bug anyway and send us the entire test case you used.
5980 A patch for the bug.
5982 A patch for the bug does help us if it is a good one. But do not omit
5983 the necessary information, such as the test case, on the assumption that
5984 a patch is all we need. We might see problems with your patch and decide
5985 to fix the problem another way, or we might not understand it at all.
5987 Sometimes with a program as complicated as @command{@value{AS}} it is very hard to
5988 construct an example that will make the program follow a certain path through
5989 the code. If you do not send us the example, we will not be able to construct
5990 one, so we will not be able to verify that the bug is fixed.
5992 And if we cannot understand what bug you are trying to fix, or why your
5993 patch should be an improvement, we will not install it. A test case will
5994 help us to understand.
5997 A guess about what the bug is or what it depends on.
5999 Such guesses are usually wrong. Even we cannot guess right about such
6000 things without first using the debugger to find the facts.
6003 @node Acknowledgements
6004 @chapter Acknowledgements
6006 If you have contributed to @command{@value{AS}} and your name isn't listed here,
6007 it is not meant as a slight. We just don't know about it. Send mail to the
6008 maintainer, and we'll correct the situation. Currently
6010 the maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}).
6012 Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any
6015 Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug
6016 information and the 68k series machines, most of the preprocessing pass, and
6017 extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}.
6019 K. Richard Pixley maintained GAS for a while, adding various enhancements and
6020 many bug fixes, including merging support for several processors, breaking GAS
6021 up to handle multiple object file format back ends (including heavy rewrite,
6022 testing, an integration of the coff and b.out back ends), adding configuration
6023 including heavy testing and verification of cross assemblers and file splits
6024 and renaming, converted GAS to strictly ANSI C including full prototypes, added
6025 support for m680[34]0 and cpu32, did considerable work on i960 including a COFF
6026 port (including considerable amounts of reverse engineering), a SPARC opcode
6027 file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know''
6028 assertions and made them work, much other reorganization, cleanup, and lint.
6030 Ken Raeburn wrote the high-level BFD interface code to replace most of the code
6031 in format-specific I/O modules.
6033 The original VMS support was contributed by David L. Kashtan. Eric Youngdale
6034 has done much work with it since.
6036 The Intel 80386 machine description was written by Eliot Dresselhaus.
6038 Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
6040 The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
6041 University and Torbjorn Granlund of the Swedish Institute of Computer Science.
6043 Keith Knowles at the Open Software Foundation wrote the original MIPS back end
6044 (@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support
6045 (which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to
6046 support a.out format.
6048 Support for the Zilog Z8k and Hitachi H8/300 and H8/500 processors (tc-z8k,
6049 tc-h8300, tc-h8500), and IEEE 695 object file format (obj-ieee), was written by
6050 Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
6051 use BFD for some low-level operations, for use with the H8/300 and AMD 29k
6054 John Gilmore built the AMD 29000 support, added @code{.include} support, and
6055 simplified the configuration of which versions accept which directives. He
6056 updated the 68k machine description so that Motorola's opcodes always produced
6057 fixed-size instructions (e.g. @code{jsr}), while synthetic instructions
6058 remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested
6059 cross-compilation support, and one bug in relaxation that took a week and
6060 required the proverbial one-bit fix.
6062 Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the
6063 68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
6064 added support for MIPS ECOFF and ELF targets, wrote the initial RS/6000 and
6065 PowerPC assembler, and made a few other minor patches.
6067 Steve Chamberlain made @command{@value{AS}} able to generate listings.
6069 Hewlett-Packard contributed support for the HP9000/300.
6071 Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM)
6072 along with a fairly extensive HPPA testsuite (for both SOM and ELF object
6073 formats). This work was supported by both the Center for Software Science at
6074 the University of Utah and Cygnus Support.
6076 Support for ELF format files has been worked on by Mark Eichin of Cygnus
6077 Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
6078 Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
6079 Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
6080 and some initial 64-bit support).
6082 Linas Vepstas added GAS support for the ESA/390 "IBM 370" architecture.
6084 Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote GAS and BFD
6085 support for openVMS/Alpha.
6087 Timothy Wall, Michael Hayes, and Greg Smart contributed to the various tic*
6090 Several engineers at Cygnus Support have also provided many small bug fixes and
6091 configuration enhancements.
6093 Many others have contributed large or small bugfixes and enhancements. If
6094 you have contributed significant work and are not mentioned on this list, and
6095 want to be, let us know. Some of the history has been lost; we are not
6096 intentionally leaving anyone out.
6098 @node GNU Free Documentation License
6099 @chapter GNU Free Documentation License
6101 GNU Free Documentation License
6103 Version 1.1, March 2000
6105 Copyright (C) 2000 Free Software Foundation, Inc.
6106 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
6108 Everyone is permitted to copy and distribute verbatim copies
6109 of this license document, but changing it is not allowed.
6114 The purpose of this License is to make a manual, textbook, or other
6115 written document "free" in the sense of freedom: to assure everyone
6116 the effective freedom to copy and redistribute it, with or without
6117 modifying it, either commercially or noncommercially. Secondarily,
6118 this License preserves for the author and publisher a way to get
6119 credit for their work, while not being considered responsible for
6120 modifications made by others.
6122 This License is a kind of "copyleft", which means that derivative
6123 works of the document must themselves be free in the same sense. It
6124 complements the GNU General Public License, which is a copyleft
6125 license designed for free software.
6127 We have designed this License in order to use it for manuals for free
6128 software, because free software needs free documentation: a free
6129 program should come with manuals providing the same freedoms that the
6130 software does. But this License is not limited to software manuals;
6131 it can be used for any textual work, regardless of subject matter or
6132 whether it is published as a printed book. We recommend this License
6133 principally for works whose purpose is instruction or reference.
6136 1. APPLICABILITY AND DEFINITIONS
6138 This License applies to any manual or other work that contains a
6139 notice placed by the copyright holder saying it can be distributed
6140 under the terms of this License. The "Document", below, refers to any
6141 such manual or work. Any member of the public is a licensee, and is
6144 A "Modified Version" of the Document means any work containing the
6145 Document or a portion of it, either copied verbatim, or with
6146 modifications and/or translated into another language.
6148 A "Secondary Section" is a named appendix or a front-matter section of
6149 the Document that deals exclusively with the relationship of the
6150 publishers or authors of the Document to the Document's overall subject
6151 (or to related matters) and contains nothing that could fall directly
6152 within that overall subject. (For example, if the Document is in part a
6153 textbook of mathematics, a Secondary Section may not explain any
6154 mathematics.) The relationship could be a matter of historical
6155 connection with the subject or with related matters, or of legal,
6156 commercial, philosophical, ethical or political position regarding
6159 The "Invariant Sections" are certain Secondary Sections whose titles
6160 are designated, as being those of Invariant Sections, in the notice
6161 that says that the Document is released under this License.
6163 The "Cover Texts" are certain short passages of text that are listed,
6164 as Front-Cover Texts or Back-Cover Texts, in the notice that says that
6165 the Document is released under this License.
6167 A "Transparent" copy of the Document means a machine-readable copy,
6168 represented in a format whose specification is available to the
6169 general public, whose contents can be viewed and edited directly and
6170 straightforwardly with generic text editors or (for images composed of
6171 pixels) generic paint programs or (for drawings) some widely available
6172 drawing editor, and that is suitable for input to text formatters or
6173 for automatic translation to a variety of formats suitable for input
6174 to text formatters. A copy made in an otherwise Transparent file
6175 format whose markup has been designed to thwart or discourage
6176 subsequent modification by readers is not Transparent. A copy that is
6177 not "Transparent" is called "Opaque".
6179 Examples of suitable formats for Transparent copies include plain
6180 ASCII without markup, Texinfo input format, LaTeX input format, SGML
6181 or XML using a publicly available DTD, and standard-conforming simple
6182 HTML designed for human modification. Opaque formats include
6183 PostScript, PDF, proprietary formats that can be read and edited only
6184 by proprietary word processors, SGML or XML for which the DTD and/or
6185 processing tools are not generally available, and the
6186 machine-generated HTML produced by some word processors for output
6189 The "Title Page" means, for a printed book, the title page itself,
6190 plus such following pages as are needed to hold, legibly, the material
6191 this License requires to appear in the title page. For works in
6192 formats which do not have any title page as such, "Title Page" means
6193 the text near the most prominent appearance of the work's title,
6194 preceding the beginning of the body of the text.
6199 You may copy and distribute the Document in any medium, either
6200 commercially or noncommercially, provided that this License, the
6201 copyright notices, and the license notice saying this License applies
6202 to the Document are reproduced in all copies, and that you add no other
6203 conditions whatsoever to those of this License. You may not use
6204 technical measures to obstruct or control the reading or further
6205 copying of the copies you make or distribute. However, you may accept
6206 compensation in exchange for copies. If you distribute a large enough
6207 number of copies you must also follow the conditions in section 3.
6209 You may also lend copies, under the same conditions stated above, and
6210 you may publicly display copies.
6213 3. COPYING IN QUANTITY
6215 If you publish printed copies of the Document numbering more than 100,
6216 and the Document's license notice requires Cover Texts, you must enclose
6217 the copies in covers that carry, clearly and legibly, all these Cover
6218 Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
6219 the back cover. Both covers must also clearly and legibly identify
6220 you as the publisher of these copies. The front cover must present
6221 the full title with all words of the title equally prominent and
6222 visible. You may add other material on the covers in addition.
6223 Copying with changes limited to the covers, as long as they preserve
6224 the title of the Document and satisfy these conditions, can be treated
6225 as verbatim copying in other respects.
6227 If the required texts for either cover are too voluminous to fit
6228 legibly, you should put the first ones listed (as many as fit
6229 reasonably) on the actual cover, and continue the rest onto adjacent
6232 If you publish or distribute Opaque copies of the Document numbering
6233 more than 100, you must either include a machine-readable Transparent
6234 copy along with each Opaque copy, or state in or with each Opaque copy
6235 a publicly-accessible computer-network location containing a complete
6236 Transparent copy of the Document, free of added material, which the
6237 general network-using public has access to download anonymously at no
6238 charge using public-standard network protocols. If you use the latter
6239 option, you must take reasonably prudent steps, when you begin
6240 distribution of Opaque copies in quantity, to ensure that this
6241 Transparent copy will remain thus accessible at the stated location
6242 until at least one year after the last time you distribute an Opaque
6243 copy (directly or through your agents or retailers) of that edition to
6246 It is requested, but not required, that you contact the authors of the
6247 Document well before redistributing any large number of copies, to give
6248 them a chance to provide you with an updated version of the Document.
6253 You may copy and distribute a Modified Version of the Document under
6254 the conditions of sections 2 and 3 above, provided that you release
6255 the Modified Version under precisely this License, with the Modified
6256 Version filling the role of the Document, thus licensing distribution
6257 and modification of the Modified Version to whoever possesses a copy
6258 of it. In addition, you must do these things in the Modified Version:
6260 A. Use in the Title Page (and on the covers, if any) a title distinct
6261 from that of the Document, and from those of previous versions
6262 (which should, if there were any, be listed in the History section
6263 of the Document). You may use the same title as a previous version
6264 if the original publisher of that version gives permission.
6265 B. List on the Title Page, as authors, one or more persons or entities
6266 responsible for authorship of the modifications in the Modified
6267 Version, together with at least five of the principal authors of the
6268 Document (all of its principal authors, if it has less than five).
6269 C. State on the Title page the name of the publisher of the
6270 Modified Version, as the publisher.
6271 D. Preserve all the copyright notices of the Document.
6272 E. Add an appropriate copyright notice for your modifications
6273 adjacent to the other copyright notices.
6274 F. Include, immediately after the copyright notices, a license notice
6275 giving the public permission to use the Modified Version under the
6276 terms of this License, in the form shown in the Addendum below.
6277 G. Preserve in that license notice the full lists of Invariant Sections
6278 and required Cover Texts given in the Document's license notice.
6279 H. Include an unaltered copy of this License.
6280 I. Preserve the section entitled "History", and its title, and add to
6281 it an item stating at least the title, year, new authors, and
6282 publisher of the Modified Version as given on the Title Page. If
6283 there is no section entitled "History" in the Document, create one
6284 stating the title, year, authors, and publisher of the Document as
6285 given on its Title Page, then add an item describing the Modified
6286 Version as stated in the previous sentence.
6287 J. Preserve the network location, if any, given in the Document for
6288 public access to a Transparent copy of the Document, and likewise
6289 the network locations given in the Document for previous versions
6290 it was based on. These may be placed in the "History" section.
6291 You may omit a network location for a work that was published at
6292 least four years before the Document itself, or if the original
6293 publisher of the version it refers to gives permission.
6294 K. In any section entitled "Acknowledgements" or "Dedications",
6295 preserve the section's title, and preserve in the section all the
6296 substance and tone of each of the contributor acknowledgements
6297 and/or dedications given therein.
6298 L. Preserve all the Invariant Sections of the Document,
6299 unaltered in their text and in their titles. Section numbers
6300 or the equivalent are not considered part of the section titles.
6301 M. Delete any section entitled "Endorsements". Such a section
6302 may not be included in the Modified Version.
6303 N. Do not retitle any existing section as "Endorsements"
6304 or to conflict in title with any Invariant Section.
6306 If the Modified Version includes new front-matter sections or
6307 appendices that qualify as Secondary Sections and contain no material
6308 copied from the Document, you may at your option designate some or all
6309 of these sections as invariant. To do this, add their titles to the
6310 list of Invariant Sections in the Modified Version's license notice.
6311 These titles must be distinct from any other section titles.
6313 You may add a section entitled "Endorsements", provided it contains
6314 nothing but endorsements of your Modified Version by various
6315 parties--for example, statements of peer review or that the text has
6316 been approved by an organization as the authoritative definition of a
6319 You may add a passage of up to five words as a Front-Cover Text, and a
6320 passage of up to 25 words as a Back-Cover Text, to the end of the list
6321 of Cover Texts in the Modified Version. Only one passage of
6322 Front-Cover Text and one of Back-Cover Text may be added by (or
6323 through arrangements made by) any one entity. If the Document already
6324 includes a cover text for the same cover, previously added by you or
6325 by arrangement made by the same entity you are acting on behalf of,
6326 you may not add another; but you may replace the old one, on explicit
6327 permission from the previous publisher that added the old one.
6329 The author(s) and publisher(s) of the Document do not by this License
6330 give permission to use their names for publicity for or to assert or
6331 imply endorsement of any Modified Version.
6334 5. COMBINING DOCUMENTS
6336 You may combine the Document with other documents released under this
6337 License, under the terms defined in section 4 above for modified
6338 versions, provided that you include in the combination all of the
6339 Invariant Sections of all of the original documents, unmodified, and
6340 list them all as Invariant Sections of your combined work in its
6343 The combined work need only contain one copy of this License, and
6344 multiple identical Invariant Sections may be replaced with a single
6345 copy. If there are multiple Invariant Sections with the same name but
6346 different contents, make the title of each such section unique by
6347 adding at the end of it, in parentheses, the name of the original
6348 author or publisher of that section if known, or else a unique number.
6349 Make the same adjustment to the section titles in the list of
6350 Invariant Sections in the license notice of the combined work.
6352 In the combination, you must combine any sections entitled "History"
6353 in the various original documents, forming one section entitled
6354 "History"; likewise combine any sections entitled "Acknowledgements",
6355 and any sections entitled "Dedications". You must delete all sections
6356 entitled "Endorsements."
6359 6. COLLECTIONS OF DOCUMENTS
6361 You may make a collection consisting of the Document and other documents
6362 released under this License, and replace the individual copies of this
6363 License in the various documents with a single copy that is included in
6364 the collection, provided that you follow the rules of this License for
6365 verbatim copying of each of the documents in all other respects.
6367 You may extract a single document from such a collection, and distribute
6368 it individually under this License, provided you insert a copy of this
6369 License into the extracted document, and follow this License in all
6370 other respects regarding verbatim copying of that document.
6373 7. AGGREGATION WITH INDEPENDENT WORKS
6375 A compilation of the Document or its derivatives with other separate
6376 and independent documents or works, in or on a volume of a storage or
6377 distribution medium, does not as a whole count as a Modified Version
6378 of the Document, provided no compilation copyright is claimed for the
6379 compilation. Such a compilation is called an "aggregate", and this
6380 License does not apply to the other self-contained works thus compiled
6381 with the Document, on account of their being thus compiled, if they
6382 are not themselves derivative works of the Document.
6384 If the Cover Text requirement of section 3 is applicable to these
6385 copies of the Document, then if the Document is less than one quarter
6386 of the entire aggregate, the Document's Cover Texts may be placed on
6387 covers that surround only the Document within the aggregate.
6388 Otherwise they must appear on covers around the whole aggregate.
6393 Translation is considered a kind of modification, so you may
6394 distribute translations of the Document under the terms of section 4.
6395 Replacing Invariant Sections with translations requires special
6396 permission from their copyright holders, but you may include
6397 translations of some or all Invariant Sections in addition to the
6398 original versions of these Invariant Sections. You may include a
6399 translation of this License provided that you also include the
6400 original English version of this License. In case of a disagreement
6401 between the translation and the original English version of this
6402 License, the original English version will prevail.
6407 You may not copy, modify, sublicense, or distribute the Document except
6408 as expressly provided for under this License. Any other attempt to
6409 copy, modify, sublicense or distribute the Document is void, and will
6410 automatically terminate your rights under this License. However,
6411 parties who have received copies, or rights, from you under this
6412 License will not have their licenses terminated so long as such
6413 parties remain in full compliance.
6416 10. FUTURE REVISIONS OF THIS LICENSE
6418 The Free Software Foundation may publish new, revised versions
6419 of the GNU Free Documentation License from time to time. Such new
6420 versions will be similar in spirit to the present version, but may
6421 differ in detail to address new problems or concerns. See
6422 http://www.gnu.org/copyleft/.
6424 Each version of the License is given a distinguishing version number.
6425 If the Document specifies that a particular numbered version of this
6426 License "or any later version" applies to it, you have the option of
6427 following the terms and conditions either of that specified version or
6428 of any later version that has been published (not as a draft) by the
6429 Free Software Foundation. If the Document does not specify a version
6430 number of this License, you may choose any version ever published (not
6431 as a draft) by the Free Software Foundation.
6434 ADDENDUM: How to use this License for your documents
6436 To use this License in a document you have written, include a copy of
6437 the License in the document and put the following copyright and
6438 license notices just after the title page:
6441 Copyright (c) YEAR YOUR NAME.
6442 Permission is granted to copy, distribute and/or modify this document
6443 under the terms of the GNU Free Documentation License, Version 1.1
6444 or any later version published by the Free Software Foundation;
6445 with the Invariant Sections being LIST THEIR TITLES, with the
6446 Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
6447 A copy of the license is included in the section entitled "GNU
6448 Free Documentation License".
6451 If you have no Invariant Sections, write "with no Invariant Sections"
6452 instead of saying which ones are invariant. If you have no
6453 Front-Cover Texts, write "no Front-Cover Texts" instead of
6454 "Front-Cover Texts being LIST"; likewise for Back-Cover Texts.
6456 If your document contains nontrivial examples of program code, we
6457 recommend releasing these examples in parallel under your choice of
6458 free software license, such as the GNU General Public License,
6459 to permit their use in free software.
projects / external / binutils.git / blob