linux-kernel - [tip:perf/core] bitops: Provide compile time HWEIGHT{8,16,32,64}

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Date:	Fri, 29 Jan 2010 09:28:04 GMT
From:	tip-bot for Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, eranian@...gle.com, hpa@...or.com,
	mingo@...hat.com, torvalds@...ux-foundation.org,
	a.p.zijlstra@...llo.nl, akpm@...ux-foundation.org,
	tglx@...utronix.de, mingo@...e.hu
Subject: [tip:perf/core] bitops: Provide compile time HWEIGHT{8,16,32,64}

Commit-ID:  9f41699ed067fa695faff8e2e9981b2550abec62
Gitweb:     http://git.kernel.org/tip/9f41699ed067fa695faff8e2e9981b2550abec62
Author:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Fri, 22 Jan 2010 15:59:29 +0100
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 29 Jan 2010 09:01:39 +0100

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

Provide compile time versions of hweight.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
LKML-Reference: <20100122155535.797688466@...llo.nl>
[ Remove some whitespace damage while we are at it ]
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 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 c05a29c..ba0fd1e 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
--
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