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    SubjectRe: [PATCH] make atomic_t volatile on all architectures
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    On Thu, 2007-08-09 at 13:36 -0400, Chuck Ebbert wrote:
    > > Fair enough. Casting to (volatile int *) will give us the behavior
    > > people expect when using atomic_t without needing to use inefficient
    > > barriers.
    > >
    >
    > You can use this forget() macro to make the compiler reread a
    > variable:
    >
    > #define forget(var) asm volatile ("" : "=m"(var))

    You need to specify a "m"(var) input constraint as well. Without it the
    compiler might remove the initialization of var. E.g.

    void fn(void)
    {
    int var = 0;
    forget(var);
    /* now var can have any value. */
    }

    --
    blue skies,
    Martin.

    "Reality continues to ruin my life." - Calvin.


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