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    SubjectRe: [patch 13/17] Immediate Values - x86 Optimization (updated)
    Mathieu Desnoyers wrote:
    >
    > Hrm, since even the nmi-safe version supports REX-prefixed instructions,
    > there is no need for an =q constraint on single-byte immediate values
    > anymore. (thanks to your "discard" section used in the nmi-safe version)
    >

    WRONG!

    Using =r for single-byte values is incorrect for 32-bit code -- that
    would permit %spl, %bpl, %sil, %dil which are illegal in 32-bit mode.
    That is not the incorrect bit, it's the description that is confused.

    -hpa


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