news@bbn.COM (News system owner ID) (10/11/88)
portable I've targeted the patterns to the IS25 instruction set. This is supposed to be a portable assembly language for the 3B series. Now with this instruction set I don't have floating point so I'm using the floating point emulation routines. My question is as follows. Each of the following patterns result in calls to emulation routines that put the result in r0 and sometimes also r1. From: rgoguen@bbn.com (Robert J Goguen) Path: bbn.com!rgoguen divdf,muldf,subdf,adddf,divsf,mulsf,subsf,addsf Question 1. Should I state that these routines clobber r0 and r1. Common sense tells me to do this except that when I use clobber gcc ends up putting the destination operand in another register even though r0 and r1 wasn't in use. So I end up having to copy r0,r1 to another register then it uses the new register. Is there someway to let gcc know that the result will be in r0/r1 so structure the code to expect it there, if you can't then use another register? Question 2. I don't have floating point registers and sometimes as in the above example gcc uses r2 for the destination register of a floating point destination. Can I assume that gcc knows the result is really in r2 and r3. For example if the destination is r2, I move low word of an emulation result into r2 and the high word of an emulation result into r3. Is this o.k. ? Question 3. #ident is not recognized as a valid thing. I'm using version 1.25 is there better support for System V in the later versions of gcc? Question 4. Presently I'm using sdb to debug the gcc built from the AT&T C compiler. I can't look at the code in insn-output.c because insn-output.c includes aux-output.c using #include "aux-output.c". Soon I will have gdb. Will gdb allow me to step through the source code or will this still be a problem? If it is still a problem is it possible to change the gen code to just open up aux-output.c and write it out to insn-output.c? Question 5. Is there a test suite that I can test the gcc compiler on? Thanks for any help. Bob Goguen