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* arch, hweight: Fix compilation errorsBorislav Petkov2010-05-041-4/+4
| | | | | | | | | | | Fix function prototype visibility issues when compiling for non-x86 architectures. Tested with crosstool (ftp://ftp.kernel.org/pub/tools/crosstool/) with alpha, ia64 and sparc targets. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> LKML-Reference: <20100503130736.GD26107@aftab> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86: Add optimized popcnt variantsBorislav Petkov2010-04-061-4/+18
| | | | | | | | | | | | | | Add support for the hardware version of the Hamming weight function, popcnt, present in CPUs which advertize it under CPUID, Function 0x0000_0001_ECX[23]. On CPUs which don't support it, we fallback to the default lib/hweight.c sw versions. A synthetic benchmark comparing popcnt with __sw_hweight64 showed almost a 3x speedup on a F10h machine. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> LKML-Reference: <20100318112015.GC11152@aftab> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* bitops: Optimize hweight() by making use of compile-time evaluationPeter Zijlstra2010-04-061-0/+11
Rename the extisting runtime hweight() implementations to __arch_hweight(), rename the compile-time versions to __const_hweight() and then have hweight() pick between them. Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100318111929.GB11152@aftab> Acked-by: H. Peter Anvin <hpa@zytor.com> LKML-Reference: <1265028224.24455.154.camel@laptop> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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