Messages in this thread | | | Date | Tue, 09 Sep 2008 13:48:51 -0400 | From | Mark Lord <> | Subject | Re: [git pull] x86 fixes |
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Mark Lord wrote: > Andi Kleen wrote: >> Krzysztof Halasa <khc@pm.waw.pl> writes: >> >>> Linus Torvalds <torvalds@linux-foundation.org> writes: >>> >>>> - "modern 32-bit": PPro and better. Can take CMOV, MMX and TSC for >>>> granted. >>> VIA C3 (Samuel 2/Ezra, 600 - 1000 MHz?, common on VIA EPIA-*: home >>> theatres etc) can't CMOV. >> >> AFAIK they fixed that in newer BIOS with a microcode update. It's >> slow, but it works. > .. > > Our firewall here uses a Via C3-600 CPU, and CMOV has never worked on it. > But based upon your posting, I have today upgraded the BIOS to the > latest (2004) version. > > Now.. how can I check whether CMOV works or not? It's not listed in > /proc/cpuinfo. ..
H. Peter Anvin wrote: > > Compile just about any C program with -march=i686. ..
Okay, done. And the binary does indeed have a ton of CMOV instructions. When running it, this appears immediately:
Illegal instruction
So much for the "BIOS upgrade fixes CMOV microcode" theory.
Cheers
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