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Commit | Line | Data |
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3b9ed1a5 | 1 | #include <linux/module.h> |
1977f032 | 2 | #include <linux/bitops.h> |
3b9ed1a5 AM |
3 | #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 | ||
12 | unsigned int hweight32(unsigned int w) | |
13 | { | |
39d997b5 AM |
14 | #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 | |
f9b41929 | 20 | unsigned int res = w - ((w >> 1) & 0x55555555); |
3b9ed1a5 | 21 | res = (res & 0x33333333) + ((res >> 2) & 0x33333333); |
f9b41929 AM |
22 | res = (res + (res >> 4)) & 0x0F0F0F0F; |
23 | res = res + (res >> 8); | |
24 | return (res + (res >> 16)) & 0x000000FF; | |
39d997b5 | 25 | #endif |
3b9ed1a5 AM |
26 | } |
27 | EXPORT_SYMBOL(hweight32); | |
28 | ||
29 | unsigned int hweight16(unsigned int w) | |
30 | { | |
f9b41929 | 31 | unsigned int res = w - ((w >> 1) & 0x5555); |
3b9ed1a5 | 32 | res = (res & 0x3333) + ((res >> 2) & 0x3333); |
f9b41929 AM |
33 | res = (res + (res >> 4)) & 0x0F0F; |
34 | return (res + (res >> 8)) & 0x00FF; | |
3b9ed1a5 AM |
35 | } |
36 | EXPORT_SYMBOL(hweight16); | |
37 | ||
38 | unsigned int hweight8(unsigned int w) | |
39 | { | |
f9b41929 | 40 | unsigned int res = w - ((w >> 1) & 0x55); |
3b9ed1a5 | 41 | res = (res & 0x33) + ((res >> 2) & 0x33); |
f9b41929 | 42 | return (res + (res >> 4)) & 0x0F; |
3b9ed1a5 AM |
43 | } |
44 | EXPORT_SYMBOL(hweight8); | |
45 | ||
46 | unsigned long hweight64(__u64 w) | |
47 | { | |
48 | #if BITS_PER_LONG == 32 | |
49 | return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w); | |
50 | #elif BITS_PER_LONG == 64 | |
0136611c AK |
51 | #ifdef ARCH_HAS_FAST_MULTIPLIER |
52 | w -= (w >> 1) & 0x5555555555555555ul; | |
53 | w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul); | |
54 | w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful; | |
55 | return (w * 0x0101010101010101ul) >> 56; | |
56 | #else | |
f9b41929 | 57 | __u64 res = w - ((w >> 1) & 0x5555555555555555ul); |
3b9ed1a5 | 58 | res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); |
f9b41929 AM |
59 | res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful; |
60 | res = res + (res >> 8); | |
61 | res = res + (res >> 16); | |
62 | return (res + (res >> 32)) & 0x00000000000000FFul; | |
0136611c | 63 | #endif |
3b9ed1a5 AM |
64 | #endif |
65 | } | |
66 | EXPORT_SYMBOL(hweight64); |