| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/export.h> |
| #include <linux/bitops.h> |
| #include <asm/types.h> |
| |
| /** |
| * hweightN - returns the hamming weight of a N-bit word |
| * @x: the word to weigh |
| * |
| * The Hamming Weight of a number is the total number of bits set in it. |
| */ |
| |
| #ifndef __HAVE_ARCH_SW_HWEIGHT |
| unsigned int __sw_hweight32(unsigned int w) |
| { |
| #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER |
| w -= (w >> 1) & 0x55555555; |
| w = (w & 0x33333333) + ((w >> 2) & 0x33333333); |
| w = (w + (w >> 4)) & 0x0f0f0f0f; |
| return (w * 0x01010101) >> 24; |
| #else |
| unsigned int res = w - ((w >> 1) & 0x55555555); |
| res = (res & 0x33333333) + ((res >> 2) & 0x33333333); |
| res = (res + (res >> 4)) & 0x0F0F0F0F; |
| res = res + (res >> 8); |
| return (res + (res >> 16)) & 0x000000FF; |
| #endif |
| } |
| EXPORT_SYMBOL(__sw_hweight32); |
| #endif |
| |
| unsigned int __sw_hweight16(unsigned int w) |
| { |
| unsigned int res = w - ((w >> 1) & 0x5555); |
| res = (res & 0x3333) + ((res >> 2) & 0x3333); |
| res = (res + (res >> 4)) & 0x0F0F; |
| return (res + (res >> 8)) & 0x00FF; |
| } |
| EXPORT_SYMBOL(__sw_hweight16); |
| |
| unsigned int __sw_hweight8(unsigned int w) |
| { |
| unsigned int res = w - ((w >> 1) & 0x55); |
| res = (res & 0x33) + ((res >> 2) & 0x33); |
| return (res + (res >> 4)) & 0x0F; |
| } |
| EXPORT_SYMBOL(__sw_hweight8); |
| |
| #ifndef __HAVE_ARCH_SW_HWEIGHT |
| unsigned long __sw_hweight64(__u64 w) |
| { |
| #if BITS_PER_LONG == 32 |
| return __sw_hweight32((unsigned int)(w >> 32)) + |
| __sw_hweight32((unsigned int)w); |
| #elif BITS_PER_LONG == 64 |
| #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER |
| w -= (w >> 1) & 0x5555555555555555ul; |
| w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul); |
| w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful; |
| return (w * 0x0101010101010101ul) >> 56; |
| #else |
| __u64 res = w - ((w >> 1) & 0x5555555555555555ul); |
| res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); |
| res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful; |
| res = res + (res >> 8); |
| res = res + (res >> 16); |
| return (res + (res >> 32)) & 0x00000000000000FFul; |
| #endif |
| #endif |
| } |
| EXPORT_SYMBOL(__sw_hweight64); |
| #endif |