1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */ 2*4882a593Smuzhiyun #ifndef _ASM_GENERIC_BITOPS_FLS_H_ 3*4882a593Smuzhiyun #define _ASM_GENERIC_BITOPS_FLS_H_ 4*4882a593Smuzhiyun 5*4882a593Smuzhiyun /** 6*4882a593Smuzhiyun * fls - find last (most-significant) bit set 7*4882a593Smuzhiyun * @x: the word to search 8*4882a593Smuzhiyun * 9*4882a593Smuzhiyun * This is defined the same way as ffs. 10*4882a593Smuzhiyun * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. 11*4882a593Smuzhiyun */ 12*4882a593Smuzhiyun fls(unsigned int x)13*4882a593Smuzhiyunstatic __always_inline int fls(unsigned int x) 14*4882a593Smuzhiyun { 15*4882a593Smuzhiyun int r = 32; 16*4882a593Smuzhiyun 17*4882a593Smuzhiyun if (!x) 18*4882a593Smuzhiyun return 0; 19*4882a593Smuzhiyun if (!(x & 0xffff0000u)) { 20*4882a593Smuzhiyun x <<= 16; 21*4882a593Smuzhiyun r -= 16; 22*4882a593Smuzhiyun } 23*4882a593Smuzhiyun if (!(x & 0xff000000u)) { 24*4882a593Smuzhiyun x <<= 8; 25*4882a593Smuzhiyun r -= 8; 26*4882a593Smuzhiyun } 27*4882a593Smuzhiyun if (!(x & 0xf0000000u)) { 28*4882a593Smuzhiyun x <<= 4; 29*4882a593Smuzhiyun r -= 4; 30*4882a593Smuzhiyun } 31*4882a593Smuzhiyun if (!(x & 0xc0000000u)) { 32*4882a593Smuzhiyun x <<= 2; 33*4882a593Smuzhiyun r -= 2; 34*4882a593Smuzhiyun } 35*4882a593Smuzhiyun if (!(x & 0x80000000u)) { 36*4882a593Smuzhiyun x <<= 1; 37*4882a593Smuzhiyun r -= 1; 38*4882a593Smuzhiyun } 39*4882a593Smuzhiyun return r; 40*4882a593Smuzhiyun } 41*4882a593Smuzhiyun 42*4882a593Smuzhiyun #endif /* _ASM_GENERIC_BITOPS_FLS_H_ */ 43