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 #include <asm/types.h> 6*4882a593Smuzhiyun 7*4882a593Smuzhiyun /** 8*4882a593Smuzhiyun * __fls - find last (most-significant) set bit in a long word 9*4882a593Smuzhiyun * @word: the word to search 10*4882a593Smuzhiyun * 11*4882a593Smuzhiyun * Undefined if no set bit exists, so code should check against 0 first. 12*4882a593Smuzhiyun */ __fls(unsigned long word)13*4882a593Smuzhiyunstatic __always_inline unsigned long __fls(unsigned long word) 14*4882a593Smuzhiyun { 15*4882a593Smuzhiyun int num = BITS_PER_LONG - 1; 16*4882a593Smuzhiyun 17*4882a593Smuzhiyun #if BITS_PER_LONG == 64 18*4882a593Smuzhiyun if (!(word & (~0ul << 32))) { 19*4882a593Smuzhiyun num -= 32; 20*4882a593Smuzhiyun word <<= 32; 21*4882a593Smuzhiyun } 22*4882a593Smuzhiyun #endif 23*4882a593Smuzhiyun if (!(word & (~0ul << (BITS_PER_LONG-16)))) { 24*4882a593Smuzhiyun num -= 16; 25*4882a593Smuzhiyun word <<= 16; 26*4882a593Smuzhiyun } 27*4882a593Smuzhiyun if (!(word & (~0ul << (BITS_PER_LONG-8)))) { 28*4882a593Smuzhiyun num -= 8; 29*4882a593Smuzhiyun word <<= 8; 30*4882a593Smuzhiyun } 31*4882a593Smuzhiyun if (!(word & (~0ul << (BITS_PER_LONG-4)))) { 32*4882a593Smuzhiyun num -= 4; 33*4882a593Smuzhiyun word <<= 4; 34*4882a593Smuzhiyun } 35*4882a593Smuzhiyun if (!(word & (~0ul << (BITS_PER_LONG-2)))) { 36*4882a593Smuzhiyun num -= 2; 37*4882a593Smuzhiyun word <<= 2; 38*4882a593Smuzhiyun } 39*4882a593Smuzhiyun if (!(word & (~0ul << (BITS_PER_LONG-1)))) 40*4882a593Smuzhiyun num -= 1; 41*4882a593Smuzhiyun return num; 42*4882a593Smuzhiyun } 43*4882a593Smuzhiyun 44*4882a593Smuzhiyun #endif /* _ASM_GENERIC_BITOPS___FLS_H_ */ 45