1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/export.h> |
3 | #include <linux/bitops.h> |
4 | #include <asm/types.h> |
5 | |
6 | /** |
7 | * hweightN - returns the hamming weight of a N-bit word |
8 | * @x: the word to weigh |
9 | * |
10 | * The Hamming Weight of a number is the total number of bits set in it. |
11 | */ |
12 | |
13 | unsigned int __sw_hweight32(unsigned int w) |
14 | { |
15 | #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER |
16 | w -= (w >> 1) & 0x55555555; |
17 | w = (w & 0x33333333) + ((w >> 2) & 0x33333333); |
18 | w = (w + (w >> 4)) & 0x0f0f0f0f; |
19 | return (w * 0x01010101) >> 24; |
20 | #else |
21 | unsigned int res = w - ((w >> 1) & 0x55555555); |
22 | res = (res & 0x33333333) + ((res >> 2) & 0x33333333); |
23 | res = (res + (res >> 4)) & 0x0F0F0F0F; |
24 | res = res + (res >> 8); |
25 | return (res + (res >> 16)) & 0x000000FF; |
26 | #endif |
27 | } |
28 | EXPORT_SYMBOL(__sw_hweight32); |
29 | |
30 | unsigned int __sw_hweight16(unsigned int w) |
31 | { |
32 | unsigned int res = w - ((w >> 1) & 0x5555); |
33 | res = (res & 0x3333) + ((res >> 2) & 0x3333); |
34 | res = (res + (res >> 4)) & 0x0F0F; |
35 | return (res + (res >> 8)) & 0x00FF; |
36 | } |
37 | EXPORT_SYMBOL(__sw_hweight16); |
38 | |
39 | unsigned int __sw_hweight8(unsigned int w) |
40 | { |
41 | unsigned int res = w - ((w >> 1) & 0x55); |
42 | res = (res & 0x33) + ((res >> 2) & 0x33); |
43 | return (res + (res >> 4)) & 0x0F; |
44 | } |
45 | EXPORT_SYMBOL(__sw_hweight8); |
46 | |
47 | unsigned long __sw_hweight64(__u64 w) |
48 | { |
49 | #if BITS_PER_LONG == 32 |
50 | return __sw_hweight32((unsigned int)(w >> 32)) + |
51 | __sw_hweight32((unsigned int)w); |
52 | #elif BITS_PER_LONG == 64 |
53 | #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER |
54 | w -= (w >> 1) & 0x5555555555555555ul; |
55 | w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul); |
56 | w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful; |
57 | return (w * 0x0101010101010101ul) >> 56; |
58 | #else |
59 | __u64 res = w - ((w >> 1) & 0x5555555555555555ul); |
60 | res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); |
61 | res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful; |
62 | res = res + (res >> 8); |
63 | res = res + (res >> 16); |
64 | return (res + (res >> 32)) & 0x00000000000000FFul; |
65 | #endif |
66 | #endif |
67 | } |
68 | EXPORT_SYMBOL(__sw_hweight64); |
69 | |