| Arnaldo Carvalho de Melo | 0aefc35 | 2015-07-09 16:27:25 -0300 | [diff] [blame] | 1 | #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 | |
| 11 | unsigned 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 | |
| 27 | unsigned 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 | |
| 35 | unsigned 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 | |
| 42 | unsigned 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 | } |