diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-18 12:17:01 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-18 12:17:01 -0400 |
commit | cb41838bbc4403f7270a94b93a9a0d9fc9c2e7ea (patch) | |
tree | 0f359975ccad4ac72e86b8edf1924c076e74bd89 /include/linux/bitops.h | |
parent | 98f01720cbe3e2eb719682777049b6514e9db556 (diff) | |
parent | c59bd5688299cddb71183e156e7a3c1409b90df2 (diff) |
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 @@ | |||
10 | #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) | 10 | #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) |
11 | #endif | 11 | #endif |
12 | 12 | ||
13 | extern unsigned int __sw_hweight8(unsigned int w); | ||
14 | extern unsigned int __sw_hweight16(unsigned int w); | ||
15 | extern unsigned int __sw_hweight32(unsigned int w); | ||
16 | extern unsigned long __sw_hweight64(__u64 w); | ||
17 | |||
13 | /* | 18 | /* |
14 | * Include this here because some architectures need generic_ffs/fls in | 19 | * Include this here because some architectures need generic_ffs/fls in |
15 | * scope | 20 | * scope |
@@ -44,31 +49,6 @@ static inline unsigned long hweight_long(unsigned long w) | |||
44 | return sizeof(w) == 4 ? hweight32(w) : hweight64(w); | 49 | return sizeof(w) == 4 ? hweight32(w) : hweight64(w); |
45 | } | 50 | } |
46 | 51 | ||
47 | /* | ||
48 | * Clearly slow versions of the hweightN() functions, their benefit is | ||
49 | * of course compile time evaluation of constant arguments. | ||
50 | */ | ||
51 | #define HWEIGHT8(w) \ | ||
52 | ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + \ | ||
53 | (!!((w) & (1ULL << 0))) + \ | ||
54 | (!!((w) & (1ULL << 1))) + \ | ||
55 | (!!((w) & (1ULL << 2))) + \ | ||
56 | (!!((w) & (1ULL << 3))) + \ | ||
57 | (!!((w) & (1ULL << 4))) + \ | ||
58 | (!!((w) & (1ULL << 5))) + \ | ||
59 | (!!((w) & (1ULL << 6))) + \ | ||
60 | (!!((w) & (1ULL << 7))) ) | ||
61 | |||
62 | #define HWEIGHT16(w) (HWEIGHT8(w) + HWEIGHT8((w) >> 8)) | ||
63 | #define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16)) | ||
64 | #define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32)) | ||
65 | |||
66 | /* | ||
67 | * Type invariant version that simply casts things to the | ||
68 | * largest type. | ||
69 | */ | ||
70 | #define HWEIGHT(w) HWEIGHT64((u64)(w)) | ||
71 | |||
72 | /** | 52 | /** |
73 | * rol32 - rotate a 32-bit value left | 53 | * rol32 - rotate a 32-bit value left |
74 | * @word: value to rotate | 54 | * @word: value to rotate |