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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 | #ifndef __HAVE_ARCH_SW_HWEIGHT | |
14 | unsigned int __sw_hweight32(unsigned int w) | |
15 | { | |
16 | #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER | |
17 | w -= (w >> 1) & 0x55555555; | |
18 | w = (w & 0x33333333) + ((w >> 2) & 0x33333333); | |
19 | w = (w + (w >> 4)) & 0x0f0f0f0f; | |
20 | return (w * 0x01010101) >> 24; | |
21 | #else | |
22 | unsigned int res = w - ((w >> 1) & 0x55555555); | |
23 | res = (res & 0x33333333) + ((res >> 2) & 0x33333333); | |
24 | res = (res + (res >> 4)) & 0x0F0F0F0F; | |
25 | res = res + (res >> 8); | |
26 | return (res + (res >> 16)) & 0x000000FF; | |
27 | #endif | |
28 | } | |
29 | EXPORT_SYMBOL(__sw_hweight32); | |
30 | #endif | |
31 | ||
32 | unsigned int __sw_hweight16(unsigned int w) | |
33 | { | |
34 | unsigned int res = w - ((w >> 1) & 0x5555); | |
35 | res = (res & 0x3333) + ((res >> 2) & 0x3333); | |
36 | res = (res + (res >> 4)) & 0x0F0F; | |
37 | return (res + (res >> 8)) & 0x00FF; | |
38 | } | |
39 | EXPORT_SYMBOL(__sw_hweight16); | |
40 | ||
41 | unsigned int __sw_hweight8(unsigned int w) | |
42 | { | |
43 | unsigned int res = w - ((w >> 1) & 0x55); | |
44 | res = (res & 0x33) + ((res >> 2) & 0x33); | |
45 | return (res + (res >> 4)) & 0x0F; | |
46 | } | |
47 | EXPORT_SYMBOL(__sw_hweight8); | |
48 | ||
49 | #ifndef __HAVE_ARCH_SW_HWEIGHT | |
50 | unsigned long __sw_hweight64(__u64 w) | |
51 | { | |
52 | #if BITS_PER_LONG == 32 | |
53 | return __sw_hweight32((unsigned int)(w >> 32)) + | |
54 | __sw_hweight32((unsigned int)w); | |
55 | #elif BITS_PER_LONG == 64 | |
56 | #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER | |
57 | w -= (w >> 1) & 0x5555555555555555ul; | |
58 | w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul); | |
59 | w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful; | |
60 | return (w * 0x0101010101010101ul) >> 56; | |
61 | #else | |
62 | __u64 res = w - ((w >> 1) & 0x5555555555555555ul); | |
63 | res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); | |
64 | res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful; | |
65 | res = res + (res >> 8); | |
66 | res = res + (res >> 16); | |
67 | return (res + (res >> 32)) & 0x00000000000000FFul; | |
68 | #endif | |
69 | #endif | |
70 | } | |
71 | EXPORT_SYMBOL(__sw_hweight64); | |
72 | #endif |