Mail Archives: djgpp/1998/07/31/09:07:52
lubaldo AT adinet DOT com DOT uy wrote:
> I have GCC 2.8.1 installed.
> I have tryed the -m386, -m486, -mpentium and -mpentiumpro switches and
> they generate the exact same code... why is that?
I tried -mpentiumpro and the code miserably(?) died with SIGILL because gcc
used the conditional assigment instruction (P6 core only).
Are you sure the assembler generated doesn't have even 1 line of difference?
What are you compiling?
> I have tryed the -march=586 switch. It produces Pentium code that it is
> not compatible with earlyer CPU's, like 486, 386... but it works on my
> machine!
Who said GCC produces code that doesn't run in 486 when you use 586? Is in
the manuals? I think gcc only changes the instruction order and aligment.
What P5 instruction is used?
> I have an AMD 5x86 processor, to my knowledge, this is a 486DX
> compatible processor but it is not meant to be Pentium compatible...
True.
> so what?
Yes, so what? ;-)))
> I have tryed also the -march=686 and that it doesn't work and thats
> Ok... And the code produced by GCC with the -march=586 directive is
> different from the one produced with the -march=486 directive... so: I
> don't understand why it works... someone knows something?
I think is just reordered to exploit the P5 pipes, that's all.
> I hope I am not bothering too much with my silly intrigues...
Why? I saw worst ;-)))
SET
P.S. He is my friend, some answers are jokes.
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