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To use the GNU assembler
to assemble gcc
output, configure gcc
with the switch, --with-gnu-as
(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 interspersed with high-level language and assembly language.
$ h8300-hms-gcc -c -g -O -Wa,-alh, -L file.c-L preserves local labels, while the compiler debugging option , -g, gives the assembler the necessary debugging infor ffb mation.
Assembler options for listing output for Hitachi H8/300, H8S and H8/300H
Use the following options
to enable listing output from the assembler (the letters after -a
may be combined into one option, such as -aln).
-al
Request an output-program
assembly listing.
-as
Request a symbol table listing.
-ad
Omit debugging directives
from the listing.
High-level listings require that a compiler debugging option, like -g, be used, and that assembly listings (-al) also be requested.
Assembler listing-control directives for Hitachi H8/300
Use the following listing-control Hitachi H8/300 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). as
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
.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.