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    SubjectRe: [PATCH] Kill div64.h dupes, parenthesize do_div() macro params
    >>>>> "Bernardo" == Bernardo Innocenti <bernie@develer.com> writes:

    Bernardo> On Wednesday 02 July 2003 02:36, Andrew Morton wrote:

    Bernardo> If there are architectures where gcc doesn't implement
    Bernardo> divisions correctly, this issue should be solved in gcc, not
    Bernardo> by adding a silly macro to the kernel.

    The issue is that on 32-bit platforms, 64bit divided by 32 bit is
    handed off to a subroutine _udivdi3 which isn't linked into the
    kernel, and which in any case does a full 64 bit by 64-bit division
    (which is slow).

    Using do_div() allows one to generate near-optimal code for a 64by32
    bit division/remainder on platforms (e.g., IA32) which have problems,
    and generating something sane for other platforms (e.g., IA64).

    Platforms that never expect to deal with a 64-bit number just redefine
    the macro in terms of long. Which means that printing out long longs
    doesn't work properly on those architectures.


    --
    Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au
    You are lost in a maze of BitKeeper repositories, all slightly different.
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