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