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Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -05001#include <linux/export.h>
Jiri Slaby1977f032007-10-18 23:40:25 -07002#include <linux/bitops.h>
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -08003#include <asm/types.h>
4
5/**
6 * hweightN - returns the hamming weight of a N-bit word
7 * @x: the word to weigh
8 *
9 * The Hamming Weight of a number is the total number of bits set in it.
10 */
11
Borislav Petkovd61931d2010-03-05 17:34:46 +010012unsigned int __sw_hweight32(unsigned int w)
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080013{
Akinobu Mita39d997b2009-12-21 16:20:16 -080014#ifdef ARCH_HAS_FAST_MULTIPLIER
15 w -= (w >> 1) & 0x55555555;
16 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
17 w = (w + (w >> 4)) & 0x0f0f0f0f;
18 return (w * 0x01010101) >> 24;
19#else
Akinobu Mitaf9b41922006-03-26 01:40:00 -080020 unsigned int res = w - ((w >> 1) & 0x55555555);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080021 res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
Akinobu Mitaf9b41922006-03-26 01:40:00 -080022 res = (res + (res >> 4)) & 0x0F0F0F0F;
23 res = res + (res >> 8);
24 return (res + (res >> 16)) & 0x000000FF;
Akinobu Mita39d997b2009-12-21 16:20:16 -080025#endif
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080026}
Borislav Petkovd61931d2010-03-05 17:34:46 +010027EXPORT_SYMBOL(__sw_hweight32);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080028
Borislav Petkovd61931d2010-03-05 17:34:46 +010029unsigned int __sw_hweight16(unsigned int w)
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080030{
Akinobu Mitaf9b41922006-03-26 01:40:00 -080031 unsigned int res = w - ((w >> 1) & 0x5555);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080032 res = (res & 0x3333) + ((res >> 2) & 0x3333);
Akinobu Mitaf9b41922006-03-26 01:40:00 -080033 res = (res + (res >> 4)) & 0x0F0F;
34 return (res + (res >> 8)) & 0x00FF;
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080035}
Borislav Petkovd61931d2010-03-05 17:34:46 +010036EXPORT_SYMBOL(__sw_hweight16);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080037
Borislav Petkovd61931d2010-03-05 17:34:46 +010038unsigned int __sw_hweight8(unsigned int w)
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080039{
Akinobu Mitaf9b41922006-03-26 01:40:00 -080040 unsigned int res = w - ((w >> 1) & 0x55);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080041 res = (res & 0x33) + ((res >> 2) & 0x33);
Akinobu Mitaf9b41922006-03-26 01:40:00 -080042 return (res + (res >> 4)) & 0x0F;
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080043}
Borislav Petkovd61931d2010-03-05 17:34:46 +010044EXPORT_SYMBOL(__sw_hweight8);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080045
Borislav Petkovd61931d2010-03-05 17:34:46 +010046unsigned long __sw_hweight64(__u64 w)
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080047{
48#if BITS_PER_LONG == 32
Borislav Petkovd61931d2010-03-05 17:34:46 +010049 return __sw_hweight32((unsigned int)(w >> 32)) +
50 __sw_hweight32((unsigned int)w);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080051#elif BITS_PER_LONG == 64
Andi Kleen01366112006-09-26 10:52:38 +020052#ifdef ARCH_HAS_FAST_MULTIPLIER
53 w -= (w >> 1) & 0x5555555555555555ul;
54 w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
55 w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
56 return (w * 0x0101010101010101ul) >> 56;
57#else
Akinobu Mitaf9b41922006-03-26 01:40:00 -080058 __u64 res = w - ((w >> 1) & 0x5555555555555555ul);
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080059 res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
Akinobu Mitaf9b41922006-03-26 01:40:00 -080060 res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
61 res = res + (res >> 8);
62 res = res + (res >> 16);
63 return (res + (res >> 32)) & 0x00000000000000FFul;
Andi Kleen01366112006-09-26 10:52:38 +020064#endif
Akinobu Mita3b9ed1a2006-03-26 01:39:13 -080065#endif
66}
Borislav Petkovd61931d2010-03-05 17:34:46 +010067EXPORT_SYMBOL(__sw_hweight64);