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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-01-22 15:59:29 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-01-29 09:01:39 +0100 |
| commit | 9f41699ed067fa695faff8e2e9981b2550abec62 (patch) | |
| tree | d579511fdefee2dff6d113f7afac1149a3bb6b0d /include/linux/bitops.h | |
| parent | 8433be1184e4f22c37d4b8ed36cde529a47882f4 (diff) | |
| download | lwn-9f41699ed067fa695faff8e2e9981b2550abec62.tar.gz lwn-9f41699ed067fa695faff8e2e9981b2550abec62.zip | |
bitops: Provide compile time HWEIGHT{8,16,32,64}
Provide compile time versions of hweight.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20100122155535.797688466@chello.nl>
[ Remove some whitespace damage while we are at it ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/bitops.h')
| -rw-r--r-- | include/linux/bitops.h | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index c05a29cb9bb2..ba0fd1eb4af7 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -25,7 +25,7 @@ static __inline__ int get_bitmask_order(unsigned int count) { int order; - + order = fls(count); return order; /* We could be slightly more clever with -1 here... */ } @@ -33,7 +33,7 @@ static __inline__ int get_bitmask_order(unsigned int count) static __inline__ int get_count_order(unsigned int count) { int order; - + order = fls(count) - 1; if (count & (count - 1)) order++; @@ -45,6 +45,20 @@ static inline unsigned long hweight_long(unsigned long w) return sizeof(w) == 4 ? hweight32(w) : hweight64(w); } +#define HWEIGHT8(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)) + /** * rol32 - rotate a 32-bit value left * @word: value to rotate |