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bitops: Optimize hweight() by making use of compile-time evaluation

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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>
This commit is contained in:
Peter Zijlstra
2010-02-01 15:03:07 +01:00
committed by H. Peter Anvin
parent 0fdf86754f
commit 1527bc8b92
8 changed files with 87 additions and 58 deletions
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11
arch/ia64/include/asm/bitops.h
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@@ -437,17 +437,18 @@ __fls (unsigned long x)
* hweightN: returns the hamming weight (i.e. the number
* of bits set) of a N-bit word
*/
static __inline__ unsigned long
hweight64 (unsigned long x)
static __inline__ unsigned long __arch_hweight64(unsigned long x)
{
unsigned long result;
result = ia64_popcnt(x);
return result;
}
#define hweight32(x) (unsigned int) hweight64((x) & 0xfffffffful)
#define hweight16(x) (unsigned int) hweight64((x) & 0xfffful)
#define hweight8(x) (unsigned int) hweight64((x) & 0xfful)
#define __arch_hweight32(x) ((unsigned int) __arch_hweight64((x) & 0xfffffffful))
#define __arch_hweight16(x) ((unsigned int) __arch_hweight64((x) & 0xfffful))
#define __arch_hweight8(x) ((unsigned int) __arch_hweight64((x) & 0xfful))
#include <asm-generic/bitops/const_hweight.h>
#endif /* __KERNEL__ */