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authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 12:17:01 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-18 12:17:01 -0400
commitcb41838bbc4403f7270a94b93a9a0d9fc9c2e7ea (patch)
tree0f359975ccad4ac72e86b8edf1924c076e74bd89 /lib
parent98f01720cbe3e2eb719682777049b6514e9db556 (diff)
parentc59bd5688299cddb71183e156e7a3c1409b90df2 (diff)
Merge branch 'core-hweight-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-hweight-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, hweight: Use a 32-bit popcnt for __arch_hweight32() arch, hweight: Fix compilation errors x86: Add optimized popcnt variants bitops: Optimize hweight() by making use of compile-time evaluation
Diffstat (limited to 'lib')
-rw-r--r--lib/Makefile3
-rw-r--r--lib/hweight.c19
2 files changed, 13 insertions, 9 deletions
diff --git a/lib/Makefile b/lib/Makefile
index af759f39d4ae..9e6d3c29d73a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -39,7 +39,10 @@ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
39lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o 39lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o
40lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o 40lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
41obj-$(CONFIG_GENERIC_FIND_LAST_BIT) += find_last_bit.o 41obj-$(CONFIG_GENERIC_FIND_LAST_BIT) += find_last_bit.o
42
43CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS))
42obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o 44obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
45
43obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o 46obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
44obj-$(CONFIG_BTREE) += btree.o 47obj-$(CONFIG_BTREE) += btree.o
45obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o 48obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
diff --git a/lib/hweight.c b/lib/hweight.c
index 63ee4eb1228d..3c79d50814cf 100644
--- a/lib/hweight.c
+++ b/lib/hweight.c
@@ -9,7 +9,7 @@
9 * The Hamming Weight of a number is the total number of bits set in it. 9 * The Hamming Weight of a number is the total number of bits set in it.
10 */ 10 */
11 11
12unsigned int hweight32(unsigned int w) 12unsigned int __sw_hweight32(unsigned int w)
13{ 13{
14#ifdef ARCH_HAS_FAST_MULTIPLIER 14#ifdef ARCH_HAS_FAST_MULTIPLIER
15 w -= (w >> 1) & 0x55555555; 15 w -= (w >> 1) & 0x55555555;
@@ -24,29 +24,30 @@ unsigned int hweight32(unsigned int w)
24 return (res + (res >> 16)) & 0x000000FF; 24 return (res + (res >> 16)) & 0x000000FF;
25#endif 25#endif
26} 26}
27EXPORT_SYMBOL(hweight32); 27EXPORT_SYMBOL(__sw_hweight32);
28 28
29unsigned int hweight16(unsigned int w) 29unsigned int __sw_hweight16(unsigned int w)
30{ 30{
31 unsigned int res = w - ((w >> 1) & 0x5555); 31 unsigned int res = w - ((w >> 1) & 0x5555);
32 res = (res & 0x3333) + ((res >> 2) & 0x3333); 32 res = (res & 0x3333) + ((res >> 2) & 0x3333);
33 res = (res + (res >> 4)) & 0x0F0F; 33 res = (res + (res >> 4)) & 0x0F0F;
34 return (res + (res >> 8)) & 0x00FF; 34 return (res + (res >> 8)) & 0x00FF;
35} 35}
36EXPORT_SYMBOL(hweight16); 36EXPORT_SYMBOL(__sw_hweight16);
37 37
38unsigned int hweight8(unsigned int w) 38unsigned int __sw_hweight8(unsigned int w)
39{ 39{
40 unsigned int res = w - ((w >> 1) & 0x55); 40 unsigned int res = w - ((w >> 1) & 0x55);
41 res = (res & 0x33) + ((res >> 2) & 0x33); 41 res = (res & 0x33) + ((res >> 2) & 0x33);
42 return (res + (res >> 4)) & 0x0F; 42 return (res + (res >> 4)) & 0x0F;
43} 43}
44EXPORT_SYMBOL(hweight8); 44EXPORT_SYMBOL(__sw_hweight8);
45 45
46unsigned long hweight64(__u64 w) 46unsigned long __sw_hweight64(__u64 w)
47{ 47{
48#if BITS_PER_LONG == 32 48#if BITS_PER_LONG == 32
49 return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w); 49 return __sw_hweight32((unsigned int)(w >> 32)) +
50 __sw_hweight32((unsigned int)w);
50#elif BITS_PER_LONG == 64 51#elif BITS_PER_LONG == 64
51#ifdef ARCH_HAS_FAST_MULTIPLIER 52#ifdef ARCH_HAS_FAST_MULTIPLIER
52 w -= (w >> 1) & 0x5555555555555555ul; 53 w -= (w >> 1) & 0x5555555555555555ul;
@@ -63,4 +64,4 @@ unsigned long hweight64(__u64 w)
63#endif 64#endif
64#endif 65#endif
65} 66}
66EXPORT_SYMBOL(hweight64); 67EXPORT_SYMBOL(__sw_hweight64);