AS - the portable GNU assembler.
as [-a[cdhlns][=file]] [-D] [--defsym sym=val]
[-f] [--gstabs] [--gdwarf2] [--help] [-I dir]
[-J] [-K] [-L]
[--keep-locals] [-o objfile] [-R] [--statistics] [-v]
[-version] [--version] [-W] [--warn] [--fatal-warnings]
[-w] [-x] [-Z] [--target-help] [target-options]
Target Alpha options:
[-mdebug | -no-mdebug]
[-relax] [-g] [-Gsize]
Target ARC options:
Target ARM options:
[-mthumb-interwork] [-moabi] [-k]
Target CRIS options:
[--underscore | --no-underscore]
[--emulation=criself | --emulation=crisaout]
Target D10V options:
Target D30V options:
Target i386 options:
Target i960 options:
Target IP2K options:
Target MCORE options:
[-jsri2bsr] [-sifilter] [-relax]
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] [-mips32r2]
[-trap] [-no-break] [-break] [-no-trap]
Target MMIX options:
[--gnu-syntax] [--relax] [--no-predefined-symbols]
[--no-expand] [--no-merge-gregs] [-x]
Target PDP11 options:
[-mpic|-mno-pic] [-mall] [-mno-extensions]
Target picoJava options:
Target PowerPC options:
Target SPARC options:
correctly everything that other assemblers for the same machine would
assemble. Any exceptions are documented explicitly. This doesn't mean
as always uses the same syntax as another assembler for the same archi-
tecture; for example, we know of several incompatible versions of 680x0
assembly language syntax.
Each time you run as it assembles exactly one source program. 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 file names. The
input files are read (from left file name to right). A command line
argument (in any position) that has no special meaning is taken to be
an input file name.
If you give as no file names it attempts to read one input file from
the as standard input, which is normally your terminal. You may have
to type ctl-D to tell as there is no more program to assemble.
Use -- if you need to explicitly name the standard input file in your
If the source is empty, as produces a small, empty object file.
as may write warnings and error messages to the standard error file
(usually your terminal). This should not happen when a compiler runs
as automatically. Warnings report an assumption made so that as could
keep assembling a flawed program; errors report a grave 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 assem-
bler arguments must be separated from each other (and the -Wa) by com-
mas. For example:
gcc -c -g -O -Wa,-alh,-L file.c
This passes two options to the assembler: -alh (emit a listing to stan-
dard output with high-level and assembly source) and -L (retain local
symbols in the symbol table).
Usually you do not need to use this -Wa mechanism, since many compiler
command-line options are automatically passed to the assembler by the
compiler. (You can call the GNU compiler driver with the -v option to
see precisely what options it passes to each compilation pass, includ-
ing the assembler.)
Turn on listings, in any of a variety of ways:
-ac omit false conditionals
-ad omit debugging directives
-ah include high-level source
set the name of the listing file
You may combine these options; for example, use -aln for assembly
listing without forms processing. The =file option, if used, must
be the last one. By itself, -a defaults to -ahls.
-D Ignored. This option is accepted for script compatibility with
calls to other assemblers.
Define the symbol sym to be value before assembling the input file.
value must be an integer constant. As in C, a leading 0x indicates
a hexadecimal value, and a leading 0 indicates an octal value.
-f ``fast''---skip whitespace and comment preprocessing (assume source
is compiler output).
Generate stabs debugging information for each assembler line. This
may help debugging assembler code, if the debugger can handle it.
Generate DWARF2 debugging information for each assembler line.
This may help debugging assembler code, if the debugger can handle
it. Note - this option is only supported by some targets, not all
Print a summary of the command line options and exit.
Print a summary of all target specific options and exit.
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.
Keep (in the symbol table) local symbols. On traditional a.out
systems these start with L, but different systems have different
local label prefixes.
Set the maximum width, in words, of the output data column for an
assembler listing to number.
Set the maximum width, in words, of the output data column for con-
tinuation lines in an assembler listing to number.
Set the maximum width of an input source line, as displayed in a
listing, to number bytes.
Print the maximum space (in bytes) and total time (in seconds) used
Remove local absolute symbols from the outgoing symbol table.
Print the as version.
Print the as version and exit.
Suppress warning messages.
Treat warnings as errors.
Don't suppress warning messages or treat them as errors.
-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 for an ARC
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 ARM
Specify which ARM processor variant is the target.
Specify which ARM architecture variant is used by the target.
Select which Floating Point architecture is the target.
Enable Thumb only instruction decoding.
Thumb and ARM 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 for a D10V
-O Optimize output by parallelizing instructions.
The following options are available when as is configured for a D30V
-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 the Intel
-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.
Do not alter compare-and-branch instructions for long displace-
ments; error if necessary.
The following options are available when as is configured for the Ubi-
com IP2K series.
Specifies that the extended IP2022 instructions are allowed.
Restores the default behaviour, which restricts the permitted
instructions to just the basic IP2022 ones.
The following options are available when as is configured for the Mit-
subishi M32R series.
Specify which processor in the M32R family is the target. The
default is normally the M32R, but this option changes it to the
--warn-explicit-parallel-conflicts or --Wp
Produce warning messages when questionable parallel constructs are
--no-warn-explicit-parallel-conflicts or --Wnp
Do not produce warning messages when questionable parallel con-
structs are encountered.
| -m68333 | -m68340 | -mcpu32 | -m5200
Specify what processor in the 68000 family is the target. The
default is normally the 68020, but this can be changed at configu-
-m68881 | -m68882 | -mno-68881 | -mno-68882
The target machine does (or does not) have a floating-point copro-
cessor. The default is to assume a coprocessor for 68020, 68030,
and cpu32. Although the basic 68000 is not compatible with the
68881, a combination of the two can be specified, since it's possi-
ble to do emulation of the coprocessor instructions with the main
-m68851 | -mno-68851
The target machine does (or does not) have a memory-management unit
coprocessor. The default is to assume an MMU for 68020 and up.
For details about the PDP-11 machine dependent features options, see
-mpic | -mno-pic
Generate position-independent (or position-dependent) code. The
default is -mpic.
Enable all instruction set extensions. This is the default.
Disable all instruction set extensions.
-mextension | -mno-extension
Enable (or disable) a particular instruction set extension.
Enable the instruction set extensions supported by a particular
CPU, and disable all other extensions.
Enable the instruction set extensions supported by a particular
machine model, and disable all other extensions.
The following options are available when as is configured for a pico-
-mb Generate ``big endian'' format output.
-ml Generate ``little endian'' format output.
The following options are available when as is configured for the
Motorola 68HC11 or 68HC12 series.
-m68hc11 | -m68hc12 | -m68hcs12
Specify what processor is the target. The default is defined by
the configuration option when building the assembler.
Specify to use the 64-bit double ABI.
Relative branches are turned into absolute ones. This concerns con-
ditional branches, unconditional branches and branches to a sub
-S | --short-branchs
Do not turn relative branchs into absolute ones when the offset is
out of range.
Do not turn the direct addressing mode into extended addressing
mode when the instruction does not support direct addressing mode.
Print the syntax of instruction in case of error.
print the list of instructions with syntax and then exit.
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 configured for the SPARC
-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 with Ultra-
-xarch=v8plus | -xarch=v8plusa
For compatibility with the Solaris v9 assembler. These options are
equivalent to -Av8plus and -Av8plusa, respectively.
Warn when the assembler switches to another architecture.
The following options are available when as is configured for a MIPS
This option sets the largest size of an object that can be refer-
enced implicitly with the "gp" register. It is only accepted for
targets that use 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.
Generate code for a particular MIPS Instruction Set Architecture
level. -mips1 is an alias for -march=r3000, -mips2 is an alias for
-march=r6000, -mips3 is an alias for -march=r4000 and -mips4 is an
alias for -march=r8000. -mips5, -mips32, -mips32r2, and -mips64
correspond to generic MIPS V, MIPS32, MIPS32 Release 2, and MIPS64
ISA processors, respectively.
Generate code for a particular MIPS cpu.
Schedule and tune for a particular MIPS cpu.
Cause nops to be inserted if the read of the destination register
of an mfhi or mflo instruction occurs in the following two instruc-
Cause stabs-style debugging output to go into an ECOFF-style .mde-
bug section instead of the standard ELF .stabs sections.
The register sizes are normally inferred from the ISA and ABI, but
these flags force a certain group of registers to be treated as 32
bits wide at all times. -mgp32 controls the size of general-pur-
pose registers and -mfp32 controls the size of floating-point reg-
Generate code for the MIPS 16 processor. This is equivalent to
putting ".set mips16" at the start of the assembly file.
-no-mips16 turns off this option.
Generate code for the MIPS-3D Application Specific Extension. This
tells the assembler to accept MIPS-3D instructions. -no-mips3d
turns off this option.
Generate code for the MDMX Application Specific Extension. This
tells the assembler to accept MDMX instructions. -no-mdmx turns
off this option.
The --no-construct-floats option disables the construction of dou-
ble width floating point constants by loading the two halves of the
value into the two single width floating point registers that make
up the double width register. By default --construct-floats is
selected, allowing construction of these floating point constants.
mary target for which the assembler was configured; the others
change the default to little- or big-endian as indicated by the b
or l in the name. Using -EB or -EL will override the endianness
selection in any case.
This option is currently supported only when the primary target as
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 for the other format, if
both are to be available. For example, the Irix 5 configuration
includes support for both.
Eventually, this option will support more configurations, with more
fine-grained control over the assembler's behavior, and will be
supported for more processors.
as ignores this option. It is accepted for compatibility with the
Control how to deal with multiplication overflow and division by
zero. --trap or --no-break (which are synonyms) take a trap excep-
tion (and only work for Instruction Set Architecture level 2 and
higher); --break or --no-trap (also synonyms, and the default) take
a break exception.
-n When this option is used, as will issue a warning every time it
generates a nop instruction from a macro.
The following options are available when as is configured for an MCore
Enable or disable the JSRI to BSR transformation. By default this
is enabled. The command line option -nojsri2bsr can be used to
Enable or disable the silicon filter behaviour. By default this is
disabled. The default can be overridden by the -sifilter command
Alter jump instructions for long displacements.
Select the cpu type on the target hardware. This controls which
instructions can be assembled.
-EB Assemble for a big endian target.
Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
Texts. A copy of the license is included in the section entitled "GNU
Free Documentation License".
binutils-18.104.22.168.18 2003-02-24 as(1)