command produces an object file from the concatenation
of the named assembly language input files.
The default is to generate the object file in COFF format,
unless the option -b elf is used, in which case an ELF
binary is produced.
There must be at least one file argument, except when
the -V option is given.
Multiple input files are not allowed when generating a COFF binary.
When the option -b elf is used, there can be multiple input files
and the name -, designating the standard input,
can appear anywhere within the list of files.
The recognized assembly language
does not include a general macro processing capability.
provides for optional preprocessing of the input by the
The following options are common to producing both types
of binary and may be specified in any order:
Produce the binary in type format. type can be
one of coff (default), ibcs2 (equivalent to
coff) and elf.
The default is to produce the object file in COFF format.
Run the m4 macro processor
on the input prior to assembly.
All file operands are passed unmodified to the
If the predefined macros file,
LIBDIR/cm4defs, is present, it
is given to the
command as the initial input file.
options can also be preserved and passed through to the m4
command by using the -- option-terminator,
when the option -b elf is used.
See the ``Examples'' section.
Put the output of the assembly in the file objfile.
If this option is not used, the name of the output file depends on
the name of the input files (and the requested file format of the object file).
The default output filename is always formed
by taking the filename of the first input file that has a .s suffix
and replacing the .s with a .o suffix.
If no input filename has the .s suffix,
the output file is a.out for ELF
binaries and file.o for COFF binaries.
Write the assembler's packaging, release, and version information
on the standard error output.
As a special case,
the assembler does no other processing
if no input files are specified.
Find the m4 preprocessor (m)
and/or the file of predefined macros (d)
in directory dir instead of in the customary place.
For COFF format,
there must be a space between the -Y flag and its
Options for COFF format
These options can be used to control how the COFF binaries
are generated. They are effective only when the option
-b elf is not used.
Do not produce line number information in the object file.
Turn off long/short address optimization.
By default, address optimization takes place.
Remove (unlink) the input file after assembly is completed.
Options for ELF format
These options can be used to control how the ELF binaries
are generated. They must be used with the option
Accept input that contains COFF directives.
the object file produced is still in ELF format.
In certain circumstances, the ELF binary generated may not
be as effective as it would be in its corresponding
native COFF format.
Append the assembler's release information
to the .comment
section of the generated output object file
if yn is
(if yn is
or if no -Q option is specified),
nothing is added.
Specify the target processor to be cpu,
which may be one of 486 (the default),
pentium (the Intel Pentium processor).
This option causes code generation specifically tuned
to the selected processor.
Upon successful completion,
the exit status of as is 0,
otherwise the exit status is non-zero.
assembler directive may not work in the .text
section for COFF format binaries when optimization is performed.
Arithmetic expressions may only have one forward
referenced symbol per expression.
Wherever possible, the assembler should be accessed
through a compilation system interface program such
If the -m option (m4 macro processor
invocation) is used, keywords for m4
(index and len, for example)
cannot be used as symbols (variables, functions, labels)
in the input file since m4 cannot determine
which are assembler symbols and which are real
The following command example,
as -b elf -m -Yd,. -- -DK=7 mydefs sys/file.s
sends, in order,
./cm4defs (if it exists) and mydefs
and sys/file.s through m4
with the macro K predefined to be 7,
assembles the output of m4,
and generates the ELF object file output in
TMPDIR is usually /usr/tmp but can be
redefined by setting the environment variable TMPDIR.
See tempnam() in
language-specific message file.
See LANG in
as is not part of any
currently supported standard;
it was developed by UNIX System Laboratories, Inc. and
is used by permission.
© 2003 Commands for Programming (CP)
SCO OpenServer Release 5.0.7 -- 11 February 2003