[PATCH 07/10] bitops: Provide compile time HWEIGHT{8,16,32,64}

[Peter Zijlstra]

Provide compile time versions of hweight.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
LKML-Reference: <new-submission>
---
 include/linux/bitops.h |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

Index: linux-2.6/include/linux/bitops.h
===================================================================
--- linux-2.6.orig/include/linux/bitops.h
+++ linux-2.6/include/linux/bitops.h
@@ -45,6 +45,20 @@ static inline unsigned long hweight_long
 	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

-- 

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