1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_GENERIC_BITOPS_FLS_H_ 3 #define _ASM_GENERIC_BITOPS_FLS_H_ 4 5 /** 6 * fls - find last (most-significant) bit set 7 * @x: the word to search 8 * 9 * This is defined the same way as ffs. 10 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. 11 */ 12 13 static __always_inline int fls(unsigned int x) 14 { 15 int r = 32; 16 17 if (!x) 18 return 0; 19 if (!(x & 0xffff0000u)) { 20 x <<= 16; 21 r -= 16; 22 } 23 if (!(x & 0xff000000u)) { 24 x <<= 8; 25 r -= 8; 26 } 27 if (!(x & 0xf0000000u)) { 28 x <<= 4; 29 r -= 4; 30 } 31 if (!(x & 0xc0000000u)) { 32 x <<= 2; 33 r -= 2; 34 } 35 if (!(x & 0x80000000u)) { 36 x <<= 1; 37 r -= 1; 38 } 39 return r; 40 } 41 42 #endif /* _ASM_GENERIC_BITOPS_FLS_H_ */ 43