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    SubjectRe: Semaphore assembly-code bug


    On Fri, 29 Oct 2004, linux-os wrote:
    >
    > Linus, there is no way in hell that you are going to move
    > a value from memory into a register (pop ecx) faster than
    > you are going to do anything to the stack-pointer or
    > any other register.

    Sorry, but you're wrong.

    Learn about modern CPU's some day, and realize that cached accesses are
    fast, and pipeline stalls are relatively much more expensive.

    Now, if it was uncached, you'd have a point.

    Also think about why

    call xxx
    jmp yy

    is often much faster than

    push $yy
    jmp xxx

    and other small interesting facts about how CPU's actually work these
    days.

    Linus
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