Seeking info on gcc/gas internals

Hi,


I am on a project to modify gcc/gas to support a modified
MIPS ISA, in which to eliminate the use of condition code
for branches.


My problem is I want to add floating point compare instructions,
so the compare result is stored to an int register, rather than
set specific condition code, and following branch instruction uses
the result in the register to branch in stead of on condition code.


The desired code looks like:
c.lt.s $4, $f0, $f1 # set $r4=1, if $f0<$f1
beqz $4, label_false
rather than
c.lt.s $f0, $f1
bc1f label_false


As I approach the problem, I need to hack the gcc/gas tools
to support the new compare operations. Can anyone give me a pointer
to description/documentation on the implementation details of
the GNU cc/as tool chain?


Thank you very much for any help.


--Li Xu
lxu@rice.edu

Return to the comp.compilers page.
Search the comp.compilers archives again.