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authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 09:17:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 09:17:01 -0700
commitcb41838bbc4403f7270a94b93a9a0d9fc9c2e7ea (patch)
tree0f359975ccad4ac72e86b8edf1924c076e74bd89 /include/linux/bitops.h
parent98f01720cbe3e2eb719682777049b6514e9db556 (diff)
parentc59bd5688299cddb71183e156e7a3c1409b90df2 (diff)
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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.h30
1 files changed, 5 insertions, 25 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index b796eab..fc68053 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
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