To use the GNU assembler, as, to assemble gcc output, configure gcc with the --with-gnu-as switch (in GNUPro Toolkit distributions) or with the -mgas option.
-Wa
If you invoke as
through the GNU C compiler (version 2), you can use the -Wa
option to pass arguments through to the assembler. One common use of this
option is to exploit the assemblers listing features.
Assembler arguments that you specify with gcc
-Wa
must be separated from each other (and the -Wa)
by commas.
-L
The additional assembler
option, -L,
preserves local labels, which may make the listing output more intelligible
to humans.
For example, in the following commandline, the assembler option ,-ahl,
requests a listing with interspersed high-level language and assembly language.
$ m68k-coff-gcc -c -g -O -Wa,- ffb alh,-L file.c-L preserves local labels, while the compiler debugging option, -g, gives the assembler the necessary debugging information.
Assembler options for listing output for m68k
Use the following options
to enable listing output from the assembler (the letters after -a
may be combined into one option, such as -al).
-ah
Requests a high-level language
listing.
-al
Request an output-program
assembly listing.
-as
Requests a symbol table
listing.
-ad
Omits debugging directives
from the listing.
High-level listings require using a compiler debugging option like -g, and that assembly listings (-al) also be requested.
Assembler listing-control directives for m68k
Use the following listing-control
assembler directives to control the appearance of the listing output (if
you do not request listing output with one of the -a
options, the following listing-control directives have no effect).
.nolist
Turn off listings from this
point on.
.psize linecount, columnwidth
Describe the page size for
your output (the default is 60, 200). The assembler generates form feeds
after printing each group of linecount
lines. To avoid these automatic form feeds, specify 0
as the linecount.
.eject
Skip to a new page (issue
a form feed).
.title
Use heading
as the title (this is the second line of the listing output, directly after
the source file name and page number) when generating assembly listings.
.sbttl
Use subheading
as the subtitle (this is the third line of the listing output, directly
after the title line) when generating assembly listings.
-an
Turn off all forms processing.