blob: 0b859b8843390fe4ba09b06f388ff31843f13d33 [file] [log] [blame]
Arnaldo Carvalho de Melo0aefc352015-07-09 16:27:25 -03001#include <linux/bitops.h>
2#include <asm/types.h>
3
4/**
5 * hweightN - returns the hamming weight of a N-bit word
6 * @x: the word to weigh
7 *
8 * The Hamming Weight of a number is the total number of bits set in it.
9 */
10
11unsigned int __sw_hweight32(unsigned int w)
12{
13#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
14 w -= (w >> 1) & 0x55555555;
15 w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
16 w = (w + (w >> 4)) & 0x0f0f0f0f;
17 return (w * 0x01010101) >> 24;
18#else
19 unsigned int res = w - ((w >> 1) & 0x55555555);
20 res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
21 res = (res + (res >> 4)) & 0x0F0F0F0F;
22 res = res + (res >> 8);
23 return (res + (res >> 16)) & 0x000000FF;
24#endif
25}
26
27unsigned int __sw_hweight16(unsigned int w)
28{
29 unsigned int res = w - ((w >> 1) & 0x5555);
30 res = (res & 0x3333) + ((res >> 2) & 0x3333);
31 res = (res + (res >> 4)) & 0x0F0F;
32 return (res + (res >> 8)) & 0x00FF;
33}
34
35unsigned int __sw_hweight8(unsigned int w)
36{
37 unsigned int res = w - ((w >> 1) & 0x55);
38 res = (res & 0x33) + ((res >> 2) & 0x33);
39 return (res + (res >> 4)) & 0x0F;
40}
41
42unsigned long __sw_hweight64(__u64 w)
43{
44#if BITS_PER_LONG == 32
45 return __sw_hweight32((unsigned int)(w >> 32)) +
46 __sw_hweight32((unsigned int)w);
47#elif BITS_PER_LONG == 64
48#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
49 w -= (w >> 1) & 0x5555555555555555ul;
50 w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
51 w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
52 return (w * 0x0101010101010101ul) >> 56;
53#else
54 __u64 res = w - ((w >> 1) & 0x5555555555555555ul);
55 res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
56 res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
57 res = res + (res >> 8);
58 res = res + (res >> 16);
59 return (res + (res >> 32)) & 0x00000000000000FFul;
60#endif
61#endif
62}