| | 1 | #include <linux/module.h> |
| | 2 | #include <linux/bitops.h> |
| | 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 __sw_hweight32(unsigned int w) |
| | 13 | { |
| | 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 |
| | 20 | unsigned int res = w - ((w >> 1) & 0x55555555); |
| | 21 | res = (res & 0x33333333) + ((res >> 2) & 0x33333333); |
| | 22 | res = (res + (res >> 4)) & 0x0F0F0F0F; |
| | 23 | res = res + (res >> 8); |
| | 24 | return (res + (res >> 16)) & 0x000000FF; |
| | 25 | #endif |
| | 26 | } |
| | 27 | EXPORT_SYMBOL(__sw_hweight32); |
| | 28 | |
| | 29 | unsigned int __sw_hweight16(unsigned int w) |
| | 30 | { |
| | 31 | unsigned int res = w - ((w >> 1) & 0x5555); |
| | 32 | res = (res & 0x3333) + ((res >> 2) & 0x3333); |
| | 33 | res = (res + (res >> 4)) & 0x0F0F; |
| | 34 | return (res + (res >> 8)) & 0x00FF; |
| | 35 | } |
| | 36 | EXPORT_SYMBOL(__sw_hweight16); |
| | 37 | |
| | 38 | unsigned int __sw_hweight8(unsigned int w) |
| | 39 | { |
| | 40 | unsigned int res = w - ((w >> 1) & 0x55); |
| | 41 | res = (res & 0x33) + ((res >> 2) & 0x33); |
| | 42 | return (res + (res >> 4)) & 0x0F; |
| | 43 | } |
| | 44 | EXPORT_SYMBOL(__sw_hweight8); |
| | 45 | |
| | 46 | unsigned long __sw_hweight64(__u64 w) |
| | 47 | { |
| | 48 | #if BITS_PER_LONG == 32 |
| | 49 | return __sw_hweight32((unsigned int)(w >> 32)) + |
| | 50 | __sw_hweight32((unsigned int)w); |
| | 51 | #elif BITS_PER_LONG == 64 |
| | 52 | #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 |
| | 58 | __u64 res = w - ((w >> 1) & 0x5555555555555555ul); |
| | 59 | res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); |
| | 60 | res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful; |
| | 61 | res = res + (res >> 8); |
| | 62 | res = res + (res >> 16); |
| | 63 | return (res + (res >> 32)) & 0x00000000000000FFul; |
| | 64 | #endif |
| | 65 | #endif |
| | 66 | } |
| | 67 | EXPORT_SYMBOL(__sw_hweight64); |
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