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SubjectRe: [PATCH] x86: Extend test_and_set_bit() test_and_clean_bit() to 64 bits in X86_64
On Thu, May 14, 2009 at 07:16:10AM -0700, H. Peter Anvin wrote:
> Andi Kleen wrote:
> >>>
> >> The right way to do it is to pass the proper type of register.
> >
> > For the input index register you don't actually need 64bit and for the
> > value it's typically memory anyways.
> >
>
> If you have a 64-bit operation you have a 64-bit index register. And
> you need a 64-bit index for it to handle over 2^31 (since it is signed.)

Pretty much all the bit ops and a few other operations currently have
2/4GB limits on x86-64. I don't think that's going to change.

In the kernel nothing is ever that big continuously anyways.

-Andi
--
ak@linux.intel.com -- Speaking for myself only.


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