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bitops: Provide compile time HWEIGHT{8,16,32,64}

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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>
This commit is contained in:
Peter Zijlstra 2010-01-22 15:59:29 +01:00 • committed by Ingo Molnar
parent 8433be1184
commit 9f41699ed0
1 changed files with 16 additions and 2 deletions
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18
include/linux/bitops.h
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@ -25,7 +25,7 @@
static __inline__ int get_bitmask_order(unsigned int count) static __inline__ int get_bitmask_order(unsigned int count)
{ {
int order; int order;
order = fls(count); order = fls(count);
return order; /* We could be slightly more clever with -1 here... */ 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) static __inline__ int get_count_order(unsigned int count)
{ {
int order; int order;
order = fls(count) - 1; order = fls(count) - 1;
if (count & (count - 1)) if (count & (count - 1))
order++; order++;
@ -45,6 +45,20 @@ static inline unsigned long hweight_long(unsigned long w)
return sizeof(w) == 4 ? hweight32(w) : hweight64(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 * rol32 - rotate a 32-bit value left
* @word: value to rotate * @word: value to rotate