On Wed, Aug 25, 2004 at 05:48:45PM -0700, [EMAIL PROTECTED] wrote:
> For the past few weeks I have been co-working on a private project. I
> have done allot of work on it and I would hate to have to start over.
>
> The makefile I created for this project explicitly tells the compiler
> (g++) to compile the binary using i686 (-march=pentiumpro) assembly
> instructions and internal timeings. Yet for some [explitive]
> [explitive] reason it refuses to do so and both ?file? amd ?readelf?
> tell me it always compiles for a bare i386 despite my explicit
> commands otherwise.
>
> Two questions:
> Why the [explitive] does this [explitive] thing not compile the end
> result into a i686 only binary as I asked it to?
> How the [explitive] do I fix it?
>
> I have read the gcc/g++ manual pages. I have googled. I have spent
> the past hour dedicating myself to this problem, and nothing seems to
> work.
>
> This is [b]really[/b] getting to me. Please help.
C file:
int main(int argc) {
int sam = 0;
if (argc > 1) sam = argc;
return sam;
}
Compile:
~ %% gcc -o testC test.c -mcpu=pentiumpro -march=pentiumpro -O3
Dissassembly Excerpt:
08048320 <main>:
8048320: 55 push %ebp
8048321: 31 c0 xor %eax,%eax
8048323: 89 e5 mov %esp,%ebp
8048325: 83 ec 08 sub $0x8,%esp
8048328: 8b 4d 08 mov 0x8(%ebp),%ecx
804832b: 83 e4 f0 and $0xfffffff0,%esp
804832e: 83 f9 02 cmp $0x2,%ecx
8048331: 0f 4d c1 cmovge %ecx,%eax
8048334: 89 ec mov %ebp,%esp
8048336: 5d pop %ebp
8048337: c3 ret
See that cmovge - that's a Pentium ONLY insn.
And readelf says:
Machine: Intel 80386
Is that ^^^ why you thing gcc won't make 686 programs?
1. A PPro exec is the same as a 386 exec except for the insns. ReadELF
will tell you it's a 386 exec even if you have a PPro exec.
Please comment. If it doesn't have 686 asm and could benefit from it, we
(atleast I) need more info.
P.S. I use woody with a GCC-3.3 from unstable and the ness. libs.
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