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    SubjectRe: Requested FAQ addition - Mandrake and partial-i686 platforms
    On Tue, Aug 12, 2003 at 10:48:59AM -0400, Brandon Stewart wrote:
    > Apparently, there is an issue with glibc on versions less than 2.3.1-15
    > (and maybe others), where it mistakenly treats CPUs as full i686
    > compliant when they only execute a subset of the i686 instructions. For
    > example, the VIA C3 supports pretty much everything i686 except CMOV,
    > yet the broken versions of glibc will detect it as fully i686 compliant.

    It's actually a problem that gcc assumes 686 = 686+cmov. The glibc
    isn't broken, its just compiled for gcc's view of what 686 is.

    > From someone who emailed me privately, this apparently affects K6-III
    > as well. Possibly other Cyrix or AMD CPUs are affected, though I don't
    > have a complete list.

    No. K6-III is a family 5 processor, so should get built for 586.

    > There are three possible workarounds:
    > 1) Upgrade glibc to a working version. I haven't done this myself, so I
    > don't know if the bug has been fixed yet. But it would be the best solution.

    Its not a glibc bug.

    > 2) Remove i686 libraries from glibc. This can be done by 'mv /lib/i686
    > /lib/i686.invalid'. This is what I did, and it works. While some
    > performance is lost, it's not noticeable, especially given that the
    > stock Mandrake kernel is i386 compatible, and so has limited optimization.

    This is the best of the bunch, and is the same solution debian users
    were using for some time a while back when someone made a '686' version
    of libssl.

    Dave

    --
    Dave Jones http://www.codemonkey.org.uk
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