AS(1) AS(1)
NAME
as - SGI MIPSpro Assembler
SYNOPSIS
as [ -o32 | -n32 | -64 ] [ option ] ... file ...
DESCRIPTION
as is the SGI assembler. It assembles a symbolic assembly language
source program, producing an object file in elf format. The SGI
assembler support three different Application Binary Interfaces
controlled by the options -o32 , -n32 , and -64 (see abi(5) ) As never
runs the loader.
as always defines the preprocessor symbols: _LANGUAGE_ASSEMBLY, __sgi,
__mips, __host_mips, __unix, _MIPSEB, _SYSTYPE_SVR4, _SVR4_SOURCE,
_SGI_SOURCE, _MIPS_ISA, _MIPS_SIM, _MIPS_FPSET, _MIPS_SZINT,
_MIPS_SZLONG, and _MIPS_SZPTR. These are shown by the -show option to
as(1). The C preprocessor adds other standard definitions of its own
(see cpp(1)).
The following options are interpreted by as and have the same meaning in
cc(1). See ld(1) for load-time options.
Commandline Options
This first set of options control the choice of ABI and ISA (Instruction
Set Architecture).
-o32 or -32
Generate a 32-bit object. This is the default on all systems that
are not based on the R8000. This implies -mips2 if -mips1 has not
been specified.
-64 Generate a 64-bit object. This is the default on R8000 systems.
This implies -mips4 if -mips3 has not been specified.
-n32 Generate an n32 object. This implies -mips3 if -mips4 has not been
specified.
-mips1
Generate code using the instruction set of the R3000 RISC
architecture. This implies -o32.
-mips2
Generate code using the MIPS II instruction set (MIPS I + some R4000
specific extensions). This implies -o32.
-mips3
Generate code using the full R4000 instruction set. This implies
-n32 (except on R8000-based systems it implies -64)
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-mips4
Generate code using the full MIPS IV instruction set (64-bit R8000
extensions). This implies -n32 (except on R8000-based systems it
implies -64)
Options valid in all three ABI's.
-cpp Run the C macro preprocessor on assembly source files before
compiling. This is the default.
-Dname=def
-Dname
Define the name to the C macro preprocessor, as if by `#define'. If
no definition is given, the name is defined as "1".
-E Run only the C macro preprocessor on the specified assembly source
files, and send the result to the standard output.
-G num
Specify the maximum size, in bytes, of a data item that is to be
accessed from the global pointer. Num is assumed to be a decimal
number. If num is zero, no data is accessed from the global
pointer. The default value for num is 8 bytes when using -64 or
-n32. The default value for num is 0 when using -o32.
-g0 Have the assembler produce no symbol table information for symbolic
debugging.
-g Have the assembler produce additional symbol table information for
full symbolic debugging. This is the default.
-Idir
`#include' files whose names do not begin with `/' are always sought
first in the directory of the file argument, then in directories
specified in -I options, and finally in the standard directory
(/usr/include).
-I This option will cause `#include' files never to be searched for in
the standard directory (/usr/include).
-keep
Build and use intermediate file names with the last component of the
source file's name replacing its suffix with the conventional
suffix for the type of file (for example `.i' file for preprocessed
source). These intermediate files are not removed. This option is
primarily for compiler debugging.
-nocpp
Do not run the C macro preprocessor on assembly source before
compiling.
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-nonshared
Don't generate position-independent code (PIC).
-O0 Turn off all optimizations. This is the default for -64 or -n32.
-O1 Turn on all optimizations that can be done easily. This is the
default for -o32.
-O or -O2
Turn on all optimizations. For -64 or -n32 this just means
scheduling the code; for -o32 this also means more aggressive
optimizations.
-o output
Name the final output file output. If this option is not used, the
output file is the input file name with a `.o' suffix rather than
the `.s' suffix.
-P Run only the C macro preprocessor and put the result for each `.s'
file in a corresponding `.i' file. The `.i' file has no `#' lines
in it.
-show
Print the passes as they execute with their arguments and their
input and output files.
-Uname
Remove any initial definition of name.
Commandline Options (-n32 or -64 only)
-help
This will not run the assembler, but will list all the available
options.
-woff all
Suppress all warning messages.
The options described below primarily aid compiler development and are
not generally used:
-Wa,arg1[,arg2...]
Pass the argument[s] argi to the assembler pass. The commas between
the arguments are translated into spaces.
-Ya,directory
Use the asm pass from the given directory.
Commandline Options (-o32 only)
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The options described below primarily aid compiler development and are
not generally used:
-fullasopt
Enable all the global optimizations done by the assembler. The
assembler can perform several global optimizations that are enabled
automatically for high level languages like C, Pascal and Fortran.
These optimizations are turned off by default while compiling an
assembly language source file. This is done because the
optimizations rely on the procedure calling convention to be
strictly followed. Several assembly language programs violate these
restrictions. The -fullasopt option allows enabling of these
optimizations for .s files.
-Hc Halt compiling after the pass specified by the character c,
producing an intermediate file for the next pass. The c can be [ a
]. It selects the assembler pass in the same way as the -t option.
If this option is used, the symbol table file produced and used by
the passes,is the last component of the source file with the suffix
changed to `.T' and is not removed. Please note that this switch is
non-standard and may not be supported across product lines.
-KPIC
Activates the assembler directives for generating position-
independent code (PIC). This is the default.
The options -t[hpab], -hpath, and -Bstring select a name to use for a
particular pass. These arguments are processed from left to right so
their order is significant. When the -B option is encountered, the
selection of names takes place using the last -h and -t options. These
three options must be used together.
-t[hpab]
Select the names. The names selected are those designated by the
characters following the -t option according to the following table:
Name Character
include h
cpp p
as0 a
as1 b
If the character `h' is in the -t argument then a directory is added
to the list of directories to be used in searching for `#include'
files. This directory name has the form /usr/includestring. This
directory is to contain the include files for the string release of
the compiler. The standard directory is still searched.
-hpath
Use path rather than the directory where the name is normally found.
Please note that this switch is non-standard and may not be
supported across product lines.
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-Bstring
Append string to all names specified by the -t option. If no -t
option has been processed before the -B, the -t option is assumed to
be ``hpab''. This list designates all names.
-Wc,arg1[,arg2...]
Pass the argument[s] argi to the assembler pass c. The c is one of [
pab ]. The c selects the assembler pass in the same way as the -t
option. Of particular interest are several options to affect the
various optimizations done by the assembler. Most of these assembler
optimizations are fairly new and so are perhaps more likely to have
problems than other parts of the compiler:
-Wb,-noxbb
Turn off cross basic block instruction scheduling.
-Wb,-nopeep
Turn off peephole optimizations.
-Wb,-noswpipe
Turn off software pipelining.
-Wb,-nosymregs
Turn off symbolic register renaming.
Note: these global optimizations are enabled only when optimization level
-O2 or higher is selected for high level languages or the -fullasopt
option is used for assembly language files.
If the environment variable TMPDIR is set, the value is used as the
directory to place any temporary files rather than the default /tmp.
FILES
file.o object file output
/usr/include standard `#include' file directory
(-o32 ONLY)
/tmp/ctm* temporary files
/usr/lib/cpp C macro preprocessor
/usr/lib/as0 symbolic assembly language translator
/usr/lib/as1 binary assembler and reorganizer
(-n32 and -64 ONLY)
/tmp/cmplr* temporary files
/usr/lib32/cmplrs/cpp C macro preprocessor
/usr/lib32/cmplrs/asm symbolic assembler
BUGS
The assembler attempts to continue after finding semantic errors. These
errors may result in internal errors.
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SEE ALSO
MIPSpro Assembly Language Programmer's Guide,
MIPSpro N32 ABI Guide,
MIPSpro 64-bit Porting and Transition Guide,
cc(1), what(1), getabi(3c)
DIAGNOSTICS
The diagnostics produced by the assembler are intended to be self-
explanatory.
NOTES:
The environment variable SGIABI can be used to change the default ABI
behavior to be -o32 , -n32 , or -64 ; see getabi(3c). Also, the
/etc/compiler.defaults file can be used to change default behavior. See
the cc(1) man page for more information.
The environment variables COMP_TARGET_ROOT, TOOLROOT, RLS_ID_OBJECT are
used by as while compiling the compiler itself. Their meaning is left
undefined intentionally. They should not be set in your environment.
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