MAN page from Trustix binutils-2.13.2-3tr.i586.rpm

AS

Section: GNU Development Tools (1)
Updated: 2002-12-20
Index

NAME

AS - the portable GNU assembler.

SYNOPSIS

as [-a[cdhlns][=file]] [-D] [--defsym sym=val]
[-f] [--gstabs] [--gdwarf2] [--help] [-I dir]
[-J] [-K] [-L]
[--listing-lhs-width=NUM] [--listing-lhs-width2=NUM]
[--listing-rhs-width=NUM] [--listing-cont-lines=NUM]
[--keep-locals] [-o objfile] [-R] [--statistics] [-v]
[-version] [--version] [-W] [--warn] [--fatal-warnings]
[-w] [-x] [-Z] [--target-help] [target-options]
[--|files ...]

Target Alpha options:
   [-mcpu]
   [-mdebug | -no-mdebug]
   [-relax] [-g] [-Gsize]
   [-F] [-32addr]

Target ARC options:
[-marc[5|6|7|8]]
[-EB|-EL]

Target ARM options:
   [-mcpu=processor[+extension...]]
   [-march=architecture[+extension...]]
   [-mfpu=floating-point-fromat]
   [-mthumb]
   [-EB|-EL]
   [-mapcs-32|-mapcs-26|-mapcs-float|
    -mapcs-reentrant]
   [-mthumb-interwork] [-moabi] [-k]

Target CRIS options:
   [--underscore | --no-underscore]
   [--pic] [-N]
   [--emulation=criself | --emulation=crisaout]

Target D10V options:
[-O]

Target D30V options:
[-O|-n|-N]

Target i386 options:
[--32|--64]

Target i960 options:
   [-ACA|-ACA_A|-ACB|-ACC|-AKA|-AKB|
    -AKC|-AMC]
   [-b] [-no-relax]

Target M32R options:
[--m32rx|--[no-]warn-explicit-parallel-conflicts|
--W[n]p]

Target M680X0 options:
[-l] [-m68000|-m68010|-m68020|...]

Target M68HC11 options:
   [-m68hc11|-m68hc12]
   [--force-long-branchs] [--short-branchs]
   [--strict-direct-mode] [--print-insn-syntax]
   [--print-opcodes] [--generate-example]

Target MCORE options:
[-jsri2bsr] [-sifilter] [-relax]
[-mcpu=[210|340]]

Target MIPS options:
   [-nocpp] [-EL] [-EB] [-n] [-O[optimization level]]
   [-g[debug level]] [-G num] [-KPIC] [-call_shared]
   [-non_shared] [-xgot] [--membedded-pic]
   [-mabi=ABI] [-32] [-n32] [-64] [-mfp32] [-mgp32]
   [-march=CPU] [-mtune=CPU] [-mips1] [-mips2]
   [-mips3] [-mips4] [-mips5] [-mips32] [-mips64]
   [-construct-floats] [-no-construct-floats]
   [-trap] [-no-break] [-break] [-no-trap]
   [-mfix7000] [-mno-fix7000]
   [-mips16] [-no-mips16]
   [-mips3d] [-no-mips3d]
   [-mdmx] [-no-mdmx]
   [-mdebug] [-no-mdebug]

Target MMIX options:
   [--fixed-special-register-names] [--globalize-symbols]
   [--gnu-syntax] [--relax] [--no-predefined-symbols]
   [--no-expand] [--no-merge-gregs] [-x]
   [--linker-allocated-gregs]

Target PDP11 options:
   [-mpic|-mno-pic] [-mall] [-mno-extensions]
   [-mextension|-mno-extension]
   [-mcpu] [-mmachine]

Target picoJava options:
[-mb|-me]

DESCRIPTION

GNU as is really a family of assemblers.If you use (or have used) the GNU assembler on one architecture, youshould find a fairly similar environment when you use it on anotherarchitecture. Each version has much in common with the others,including object file formats, most assembler directives (often calledpseudo-ops) and assembler syntax.

as is primarily intended to assemble the output of theGNU C compiler for use by the linker. Nevertheless, we've tried to make asassemble correctly everything that other assemblers for the samemachine would assemble.Any exceptions are documented explicitly.This doesn't mean as always uses the same syntax as anotherassembler for the same architecture; for example, we know of severalincompatible versions of 680x0 assembly language syntax.

Each time you run as it assembles exactly one sourceprogram. The source program is made up of one or more files.(The standard input is also a file.)

You give as a command line that has zero or more input filenames. The input files are read (from left file name to right). Acommand line argument (in any position) that has no special meaningis taken to be an input file name.

If you give as no file names it attempts to read one input filefrom the as standard input, which is normally your terminal. Youmay have to type ctl-D to tell as there is no more programto assemble.

Use -- if you need to explicitly name the standard input filein your command line.

If the source is empty, as produces a small, empty objectfile.

as may write warnings and error messages to the standard errorfile (usually your terminal). This should not happen when a compilerruns as automatically. Warnings report an assumption made sothat as could keep assembling a flawed program; errors report agrave problem that stops the assembly.

If you are invoking as via the GNU C compiler (version 2),you can use the -Wa option to pass arguments through to the assembler.The assembler arguments must be separated from each other (and the -Wa)by commas. For example:

        gcc -c -g -O -Wa,-alh,-L file.c

This passes two options to the assembler: -alh (emit a listing tostandard output with high-level and assembly source) and -L (retainlocal symbols in the symbol table).

Usually you do not need to use this -Wa mechanism, since many compilercommand-line options are automatically passed to the assembler by the compiler.(You can call the GNU compiler driver with the -v option to seeprecisely what options it passes to each compilation pass, including theassembler.)

OPTIONS

-a[cdhlmns]

Turn on listings, in any of a variety of ways:

-ac: omit false conditionals
-ad: omit debugging directives
-ah: include high-level source
-al: include assembly
-am: include macro expansions
-an: omit forms processing
-as: include symbols
=file: set the name of the listing file

: You may combine these options; for example, use -aln for assemblylisting without forms processing. The =file option, if used, must bethe last one. By itself, -a defaults to -ahls.

-D

Ignored. This option is accepted for script compatibility with calls toother assemblers.

--defsym sym=value

Define the symbol sym to be value before assembling the input file.value must be an integer constant. As in C, a leading 0xindicates a hexadecimal value, and a leading 0 indicates an octal value.

-f

``fast''---skip whitespace and comment preprocessing (assume source iscompiler output).

--gstabs

Generate stabs debugging information for each assembler line. Thismay help debugging assembler code, if the debugger can handle it.

--gdwarf2

Generate DWARF2 debugging information for each assembler line. Thismay help debugging assembler code, if the debugger can handle it. Note - thisoption is only supported by some targets, not all of them.

--help

Print a summary of the command line options and exit.

--target-help

Print a summary of all target specific options and exit.

-I dir

Add directory dir to the search list for ".include" directives.

-J

Don't warn about signed overflow.

-K

This option is accepted but has no effect on the TARGET family.

-L

--keep-locals

Keep (in the symbol table) local symbols. On traditional a.out systemsthese start with L, but different systems have different locallabel prefixes.

--listing-lhs-width=number

Set the maximum width, in words, of the output data column for an assemblerlisting to number.

--listing-lhs-width2=number

Set the maximum width, in words, of the output data column for continuationlines in an assembler listing to number.

--listing-rhs-width=number

Set the maximum width of an input source line, as displayed in a listing, tonumber bytes.

--listing-cont-lines=number

Set the maximum number of lines printed in a listing for a single line of inputto number + 1.

-o objfile

Name the object-file output from as objfile.

-R

Fold the data section into the text section.

--statistics

Print the maximum space (in bytes) and total time (in seconds) used byassembly.

--strip-local-absolute

Remove local absolute symbols from the outgoing symbol table.

-v

-version

Print the as version.

--version

Print the as version and exit.

-W

--no-warn

Suppress warning messages.

--fatal-warnings

Treat warnings as errors.

--warn

Don't suppress warning messages or treat them as errors.

-w

Ignored.

-x

Ignored.

-Z

Generate an object file even after errors.

-- | files ...

Standard input, or source files to assemble.

The following options are available when as is configured foran ARC processor.

-marc[5|6|7|8]: This option selects the core processor variant.
-EB | -EL: Select either big-endian (-EB) or little-endian (-EL) output.

The following options are available when as is configured for the ARMprocessor family.

-mcpu=processor[+extension...]: Specify which ARM processor variant is the target.
-march=architecture[+extension...]: Specify which ARM architecture variant is used by the target.
-mfpu=floating-point-format: Select which Floating Point architecture is the target.
-mthumb: Enable Thumb only instruction decoding.
-mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant | -moabi: Select which procedure calling convention is in use.
-EB | -EL: Select either big-endian (-EB) or little-endian (-EL) output.
-mthumb-interwork: Specify that the code has been generated with interworking between Thumb andARM code in mind.
-k: Specify that PIC code has been generated.

See the info pages for documentation of the CRIS-specific options.

The following options are available when as is configured fora D10V processor.

-O: Optimize output by parallelizing instructions.

The following options are available when as is configured for a D30Vprocessor.

-O: Optimize output by parallelizing instructions.
-n: Warn when nops are generated.
-N: Warn when a nop after a 32-bit multiply instruction is generated.

The following options are available when as is configured for theIntel 80960 processor.

-ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC: Specify which variant of the 960 architecture is the target.
-b: Add code to collect statistics about branches taken.
-no-relax: Do not alter compare-and-branch instructions for long displacements;error if necessary.

The following options are available when as is configured for theMitsubishi M32R series.

--m32rx: Specify which processor in the M32R family is the target. The defaultis normally the M32R, but this option changes it to the M32RX.
--warn-explicit-parallel-conflicts or --Wp: Produce warning messages when questionable parallel constructs areencountered.
--no-warn-explicit-parallel-conflicts or --Wnp: Do not produce warning messages when questionable parallel constructs are encountered.

The following options are available when as is configured for theMotorola 68000 series.

-l: Shorten references to undefined symbols, to one word instead of two.
-m68000 | -m68008 | -m68010 | -m68020 | -m68030
| -m68040 | -m68060 | -m68302 | -m68331 | -m68332
| -m68333 | -m68340 | -mcpu32 | -m5200: Specify what processor in the 68000 family is the target. The defaultis normally the 68020, but this can be changed at configuration time.
-m68881 | -m68882 | -mno-68881 | -mno-68882: The target machine does (or does not) have a floating-point coprocessor.The default is to assume a coprocessor for 68020, 68030, and cpu32. Althoughthe basic 68000 is not compatible with the 68881, a combination of thetwo can be specified, since it's possible to do emulation of thecoprocessor instructions with the main processor.
-m68851 | -mno-68851: The target machine does (or does not) have a memory-managementunit coprocessor. The default is to assume an MMU for 68020 and up.

For details about the PDP-11 machine dependent features options,see @ref{PDP-11-Options}.

-mpic | -mno-pic: Generate position-independent (or position-dependent) code. Thedefault is -mpic.
-mall
-mall-extensions: Enable all instruction set extensions. This is the default.
-mno-extensions: Disable all instruction set extensions.
-mextension | -mno-extension: Enable (or disable) a particular instruction set extension.
-mcpu: Enable the instruction set extensions supported by a particular CPU, anddisable all other extensions.
-mmachine: Enable the instruction set extensions supported by a particular machinemodel, and disable all other extensions.

The following options are available when as is configured fora picoJava processor.

-mb: Generate ``big endian'' format output.
-ml: Generate ``little endian'' format output.

The following options are available when as is configured for theMotorola 68HC11 or 68HC12 series.

-m68hc11 | -m68hc12: Specify what processor is the target. The default isdefined by the configuration option when building the assembler.
--force-long-branchs: Relative branches are turned into absolute ones. This concernsconditional branches, unconditional branches and branches to asub routine.
-S | --short-branchs: Do not turn relative branchs into absolute oneswhen the offset is out of range.
--strict-direct-mode: Do not turn the direct addressing mode into extended addressing modewhen the instruction does not support direct addressing mode.
--print-insn-syntax: Print the syntax of instruction in case of error.
--print-opcodes: print the list of instructions with syntax and then exit.
--generate-example: print an example of instruction for each possible instruction and then exit.This option is only useful for testing as.

The following options are available when as is configuredfor the SPARC architecture:

-Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite

-Av8plus | -Av8plusa | -Av9 | -Av9a

Explicitly select a variant of the SPARC architecture.

-Av8plus and -Av8plusa select a 32 bit environment.-Av9 and -Av9a select a 64 bit environment.

-Av8plusa and -Av9a enable the SPARC V9 instruction set withUltraSPARC extensions.

-xarch=v8plus | -xarch=v8plusa

For compatibility with the Solaris v9 assembler. These options areequivalent to -Av8plus and -Av8plusa, respectively.

-bump

Warn when the assembler switches to another architecture.

The following options are available when as is configured fora MIPS processor.

-G num

This option sets the largest size of an object that can be referencedimplicitly with the "gp" register. It is only accepted for targets thatuse ECOFF format, such as a DECstation running Ultrix. The default value is 8.

-EB

Generate ``big endian'' format output.

-EL

Generate ``little endian'' format output.

-mips1

-mips2

-mips3

-mips4

-mips5

-mips32

-mips64

Generate code for a particular MIPS Instruction Set Architecture level.-mips1 is an alias for -march=r3000, -mips2 is analias for -march=r6000, -mips3 is an alias for-march=r4000 and -mips4 is an alias for -march=r8000.-mips5, -mips32, and -mips64 correspond to genericMIPS V, MIPS32, and MIPS64 ISA processors,respectively.

-march=CPU

Generate code for a particular MIPS cpu.

-mtune=cpu

Schedule and tune for a particular MIPS cpu.

-mfix7000

-mno-fix7000

Cause nops to be inserted if the read of the destination registerof an mfhi or mflo instruction occurs in the following two instructions.

-mdebug

-no-mdebug

Cause stabs-style debugging output to go into an ECOFF-style .mdebugsection instead of the standard ELF .stabs sections.

-mgp32

-mfp32

The register sizes are normally inferred from the ISA and ABI, but theseflags force a certain group of registers to be treated as 32 bits wide atall times. -mgp32 controls the size of general-purpose registersand -mfp32 controls the size of floating-point registers.

-mips16

-no-mips16

Generate code for the MIPS 16 processor. This is equivalent to putting".set mips16" at the start of the assembly file. -no-mips16turns off this option.

-mips3d

-no-mips3d

Generate code for the MIPS-3D Application Specific Extension.This tells the assembler to accept MIPS-3D instructions.-no-mips3d turns off this option.

-mdmx

-no-mdmx

Generate code for the MDMX Application Specific Extension.This tells the assembler to accept MDMX instructions.-no-mdmx turns off this option.

--construct-floats

--no-construct-floats

The --no-construct-floats option disables the construction ofdouble width floating point constants by loading the two halves of thevalue into the two single width floating point registers that make upthe double width register. By default --construct-floats isselected, allowing construction of these floating point constants.

--emulation=name

This option causes as to emulate as configuredfor some other target, in all respects, including output format (choosingbetween ELF and ECOFF only), handling of pseudo-opcodes which may generatedebugging information or store symbol table information, and defaultendianness. The available configuration names are: mipsecoff,mipself, mipslecoff, mipsbecoff, mipslelf,mipsbelf. The first two do not alter the default endianness from thatof the primary target for which the assembler was configured; the others changethe default to little- or big-endian as indicated by the b or lin the name. Using -EB or -EL will override the endiannessselection in any case.

This option is currently supported only when the primary targetas is configured for is a MIPS ELF or ECOFF target.Furthermore, the primary target or others specified with--enable-targets=... at configuration time must include support forthe other format, if both are to be available. For example, the Irix 5configuration includes support for both.

Eventually, this option will support more configurations, with morefine-grained control over the assembler's behavior, and will be supported formore processors.

-nocpp

as ignores this option. It is accepted for compatibility withthe native tools.

--trap

--no-trap

--break

--no-break

Control how to deal with multiplication overflow and division by zero.--trap or --no-break (which are synonyms) take a trap exception(and only work for Instruction Set Architecture level 2 and higher);--break or --no-trap (also synonyms, and the default) take abreak exception.

-n

When this option is used, as will issue a warning everytime it generates a nop instruction from a macro.

The following options are available when as is configured foran MCore processor.

-jsri2bsr
-nojsri2bsr: Enable or disable the JSRI to BSR transformation. By default this is enabled.The command line option -nojsri2bsr can be used to disable it.
-sifilter
-nosifilter: Enable or disable the silicon filter behaviour. By default this is disabled.The default can be overridden by the -sifilter command line option.
-relax: Alter jump instructions for long displacements.
-mcpu=[210|340]: Select the cpu type on the target hardware. This controls which instructionscan be assembled.
-EB: Assemble for a big endian target.
-EL: Assemble for a little endian target.

See the info pages for documentation of the MMIX-specific options.

COPYRIGHT

Permission is granted to copy, distribute and/or modify this documentunder the terms of the GNU Free Documentation License, Version 1.1or any later version published by the Free Software Foundation;with no Invariant Sections, with no Front-Cover Texts, and with noBack-Cover Texts. A copy of the license is included in thesection entitled ``GNU Free Documentation License''.

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