1 #include <linux/export.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 #ifndef __HAVE_ARCH_SW_HWEIGHT __sw_hweight32(unsigned int w)13unsigned int __sw_hweight32(unsigned int w) 14 { 15 #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER 16 w -= (w >> 1) & 0x55555555; 17 w = (w & 0x33333333) + ((w >> 2) & 0x33333333); 18 w = (w + (w >> 4)) & 0x0f0f0f0f; 19 return (w * 0x01010101) >> 24; 20 #else 21 unsigned int res = w - ((w >> 1) & 0x55555555); 22 res = (res & 0x33333333) + ((res >> 2) & 0x33333333); 23 res = (res + (res >> 4)) & 0x0F0F0F0F; 24 res = res + (res >> 8); 25 return (res + (res >> 16)) & 0x000000FF; 26 #endif 27 } 28 EXPORT_SYMBOL(__sw_hweight32); 29 #endif 30 __sw_hweight16(unsigned int w)31unsigned int __sw_hweight16(unsigned int w) 32 { 33 unsigned int res = w - ((w >> 1) & 0x5555); 34 res = (res & 0x3333) + ((res >> 2) & 0x3333); 35 res = (res + (res >> 4)) & 0x0F0F; 36 return (res + (res >> 8)) & 0x00FF; 37 } 38 EXPORT_SYMBOL(__sw_hweight16); 39 __sw_hweight8(unsigned int w)40unsigned int __sw_hweight8(unsigned int w) 41 { 42 unsigned int res = w - ((w >> 1) & 0x55); 43 res = (res & 0x33) + ((res >> 2) & 0x33); 44 return (res + (res >> 4)) & 0x0F; 45 } 46 EXPORT_SYMBOL(__sw_hweight8); 47 48 #ifndef __HAVE_ARCH_SW_HWEIGHT __sw_hweight64(__u64 w)49unsigned long __sw_hweight64(__u64 w) 50 { 51 #if BITS_PER_LONG == 32 52 return __sw_hweight32((unsigned int)(w >> 32)) + 53 __sw_hweight32((unsigned int)w); 54 #elif BITS_PER_LONG == 64 55 #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER 56 w -= (w >> 1) & 0x5555555555555555ul; 57 w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul); 58 w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful; 59 return (w * 0x0101010101010101ul) >> 56; 60 #else 61 __u64 res = w - ((w >> 1) & 0x5555555555555555ul); 62 res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); 63 res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful; 64 res = res + (res >> 8); 65 res = res + (res >> 16); 66 return (res + (res >> 32)) & 0x00000000000000FFul; 67 #endif 68 #endif 69 } 70 EXPORT_SYMBOL(__sw_hweight64); 71 #endif 72