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 73