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Commit 9f41699e authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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



Provide compile time versions of hweight.

Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent 8433be11

include/linux/bitops.h

+16 −2
Original line number Diff line number Diff line
@@ -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