gasp - a preprocessor for assembly programs
gasp [-a|--alternate] [-c CHAR | --commentchar CHAR] [-d|--debug]
[-h|--help] [-M|--mri] [-o OUTFILE | --output OUTFILE]
[-p|--print] [-s|--copysource] [-u|--unreasonable]
[-v|--version] INFILE ...
The primary purpose of the GNU assembler is to assemble the output of
other programs--notably compilers. When you have to hand-code
specialized routines in assembly, that means the GNU assembler is an
unfriendly processor: it has no directives for macros, conditionals, or
many other conveniences that you might expect.
In some cases you can simply use the C preprocessor, or a generalized
preprocessor like M4; but this can be awkward, since none of these
things are designed with assembly in mind.
gasp fills this need. It is expressly designed to provide the
facilities you need with hand-coded assembly code. Implementing it as
a preprocessor, rather than part of the assembler, allows the maximum
flexibility: you can use it with hand-coded assembly, without paying a
penalty of added complexity in the assembler you use for compiler
INFILE... are the files to be preprocessed.
The simplest way to use GASP is to run it as a filter and assemble its
output. In Unix and its ilk, you can do this, for example:
$ gasp prog.asm | as -o prog.o
Naturally, there are also a few command-line options to allow you to
request variations on this basic theme. Here is the full set of
possibilities for the GASP command line.
Use alternative macro syntax. *Note Alternate macro syntax:
Alternate, for a discussion of how this syntax differs from the
default GASP syntax.
Use CHAR as the comment character. The default comment
character is `!'. For example, to use a semicolon as the
comment character, specify `-c ';'' on the GASP command line.
Since assembler command characters often have special
significance to command shells, it is a good idea to quote or
escape CHAR when you specify a comment character.
For the sake of simplicity, all examples in this manual use the
default comment character `!'.
Show debugging statistics. In this version of GASP, this option
produces statistics about the string buffers that GASP allocates
internally. For each defined buffersize S, GASP shows the
number of strings N that it allocated, with a line like this:
strings size S : N
GASP displays these statistics on the standard error stream,
when done preprocessing.
--help Display a summary of the GASP command line options.
--mri Use MRI compatibility mode. Using this option causes GASP to
accept the syntax and pseudo-ops used by the Microtec Research
`-o OUTFILE' `--output OUTFILE' Write the output in a file
called OUTFILE. If you do not use the `-o' option, GASP writes
its output on the standard output stream.
Print line numbers. GASP obeys this option _only_ if you also
specify `-s' to copy source lines to its output. With `-s -p',
GASP displays the line number of each source line copied
(immediately after the comment character at the beginning of the
Copy the source lines to the output file. Use this option to
see the effect of each preprocessor line on the GASP output.
GASP places a comment character (`!' by default) at the
beginning of each source line it copies, so that you can use
this option and still assemble the result.
Bypass "unreasonable expansion" limit. Since you can define
GASP macros inside other macro definitions, the preprocessor
normally includes a sanity check. If your program requires more
than 1,000 nested expansions, GASP normally exits with an error
message. Use this option to turn off this check, allowing
unlimited nested expansions.
Display the GASP version number.
The input file names. You must specify at least one input file;
if you specify more, GASP preprocesses them all, concatenating
the output in the order you list the INFILE arguments.
Mark the end of each input file with the preprocessor command
`gasp' entry in info; The GNU Binary Utilities, Roland H. Pesch
(October 1991); gasp(1).