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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@chello.nl>
AuthorDate: Fri, 22 Jan 2010 15:59:29 +0100
Committer: Ingo Molnar <mingo@elte.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@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>
---
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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