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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-18 20:17:01 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-18 20:17:01 +0400 |
| commit | cb41838bbc4403f7270a94b93a9a0d9fc9c2e7ea (patch) | |
| tree | 0f359975ccad4ac72e86b8edf1924c076e74bd89 /include/linux/bitops.h | |
| parent | 98f01720cbe3e2eb719682777049b6514e9db556 (diff) | |
| parent | c59bd5688299cddb71183e156e7a3c1409b90df2 (diff) | |
| download | linux-cb41838bbc4403f7270a94b93a9a0d9fc9c2e7ea.tar.xz | |
Merge branch 'core-hweight-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-hweight-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, hweight: Use a 32-bit popcnt for __arch_hweight32()
arch, hweight: Fix compilation errors
x86: Add optimized popcnt variants
bitops: Optimize hweight() by making use of compile-time evaluation
Diffstat (limited to 'include/linux/bitops.h')
| -rw-r--r-- | include/linux/bitops.h | 30 |
1 files changed, 5 insertions, 25 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index b796eab5ca75..fc68053378ce 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -10,6 +10,11 @@ #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) #endif +extern unsigned int __sw_hweight8(unsigned int w); +extern unsigned int __sw_hweight16(unsigned int w); +extern unsigned int __sw_hweight32(unsigned int w); +extern unsigned long __sw_hweight64(__u64 w); + /* * Include this here because some architectures need generic_ffs/fls in * scope @@ -44,31 +49,6 @@ static inline unsigned long hweight_long(unsigned long w) return sizeof(w) == 4 ? hweight32(w) : hweight64(w); } -/* - * Clearly slow versions of the hweightN() functions, their benefit is - * of course compile time evaluation of constant arguments. - */ -#define HWEIGHT8(w) \ - ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + \ - (!!((w) & (1ULL << 0))) + \ - (!!((w) & (1ULL << 1))) + \ - (!!((w) & (1ULL << 2))) + \ - (!!((w) & (1ULL << 3))) + \ - (!!((w) & (1ULL << 4))) + \ - (!!((w) & (1ULL << 5))) + \ - (!!((w) & (1ULL << 6))) + \ - (!!((w) & (1ULL << 7))) ) - -#define HWEIGHT16(w) (HWEIGHT8(w) + HWEIGHT8((w) >> 8)) -#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16)) -#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32)) - -/* - * Type invariant version that simply casts things to the - * largest type. - */ -#define HWEIGHT(w) HWEIGHT64((u64)(w)) - /** * rol32 - rotate a 32-bit value left * @word: value to rotate |