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    SubjectRe: X32 psABI status
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    On Sun, Feb 13, 2011 at 3:39 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
    >> a. the int $0x80 instruction is much slower than syscall.  An actual
    >>    i386 process can use the syscall instruction which is disambiguated
    >>    by the CPU based on mode, but an x32 process is in the same CPU mode
    >>    as a normal 64-bit process.
    >
    > So set a flag, whoopee
    >
    >> b. 64-bit arguments have to be split between two registers for the
    >>    i386 entry points, requiring user-space stubs.
    >
    > Diddums. Given you've yet to explain why everyone desperately needs this
    > extra interface why do we care ?
    >
    >> All in all, the cost of an extra system call table is quite modest.
    >
    > And the cost of not doing it is a gloriously wonderful zero. Yo've still
    > not explained the justification or what large number of apps are going to
    > use it.
    >
    > It's a simple question - why do we care, why do we want the overhead and
    > the hassle, what do users get in return ?
    >

    The real question is if we need to use ia32. If the answer is yes, then
    x32 provides the benefit of ia32 with register extended to 64bit plus 8
    more registers as well as IP relative address.

    --
    H.J.
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