On Mon, 2003-07-21 at 10:14, Audioslave - 7M3 - Live wrote: > Back to the athlon being such a used processor. What makes the processor > not to be able to deal with i686 instructions? And why does it include > i386 compatible instructions? > The Athlon is able to deal with i686 instructions, I think - RH packages are compiled optimised for i686 but using only the i486 (not i386) instruction set to ensure compatibility on 486s and Pentiums. Compiling with -mcpu=i586 is *bad* because the Pentium is considered broken in requiring special instruction orderings that would actually slow down execution on other CPUs. That being said, -march=i586 might be safe - Mandrake does it, as does Gentoo, if I recall, but I wonder if there is much advantage to it. The only Athlon-specific bug Red Hat had was when one of the Athlon chips was first introduced - can't remember which one, I think it's the second-generation chip - and a replacement boot floppy was issued within a week. > MMX seemed useless for my machine. PII optimization seemed useful. I > might be able to get on a P4 to see how buggy it is or how much better > the programs run. It is a Dell computer. > MMX is a vector instruction set. Recompiling a non-MMX-aware program with MMX optimisation would not achieve anything. Regards, Michel -- Shrike-list mailing list Shrike-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/shrike-list
