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    SubjectRe: can somebody explain barrier() macro ?
    On Tue, Feb 20, 2001 at 12:50:54PM -0700, hiren_mehta@agilent.com wrote:
    > barrier() is defined in kernel.h as follows :
    >
    > #define barrier() __asm__ __volatile__("": : :"memory")
    >
    > what does this mean ? is this like "nop" ?

    It's a write barrier. It prevents the compiler from optimising writes
    to memory: all outstanding writes should be done before the program
    flow crosses the barrier().


    Erik

    --
    J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
    of Electrical Engineering, Faculty of Information Technology and Systems,
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    Phone: +31-15-2783635 Fax: +31-15-2781843 Email: J.A.K.Mouw@its.tudelft.nl
    WWW: http://www-ict.its.tudelft.nl/~erik/
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