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    SubjectRe: i686 quirk for AMD Geode
    On 11/10/2009 11:50 AM, Avi Kivity wrote:
    >>
    >> Consider SSE3, for example. Why should the same concept not apply to
    >> SSE3 instructions as to CMOV?
    >
    > Because then user programs would run 20x or more slower than the user
    > expects. Better to terminate early (and teach userspace how to choose
    > the instruction subset correctly).
    >

    I picked the example carefully: SSE3 is a small set of instructions
    which probably aren't used very heavily. In that sense, it has
    *exactly* the same properties as CMOV - if you have the source, you're
    better off recompiling, but it *might* help you if you happen to only
    have a binary.

    What I want people to understand is that this is a *huge* rathole, and
    it doesn't have any obvious bottom that I can see.

    -hpa


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