1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_GENERIC_BITOPS___FFS_H_ 3 #define _ASM_GENERIC_BITOPS___FFS_H_ 4 5 #include <asm/types.h> 6 7 /** 8 * generic___ffs - find first bit in word. 9 * @word: The word to search 10 * 11 * Undefined if no bit exists, so code should check against 0 first. 12 */ 13 static __always_inline unsigned int generic___ffs(unsigned long word) 14 { 15 unsigned int num = 0; 16 17 #if BITS_PER_LONG == 64 18 if ((word & 0xffffffff) == 0) { 19 num += 32; 20 word >>= 32; 21 } 22 #endif 23 if ((word & 0xffff) == 0) { 24 num += 16; 25 word >>= 16; 26 } 27 if ((word & 0xff) == 0) { 28 num += 8; 29 word >>= 8; 30 } 31 if ((word & 0xf) == 0) { 32 num += 4; 33 word >>= 4; 34 } 35 if ((word & 0x3) == 0) { 36 num += 2; 37 word >>= 2; 38 } 39 if ((word & 0x1) == 0) 40 num += 1; 41 return num; 42 } 43 44 #ifndef __HAVE_ARCH___FFS 45 #define __ffs(word) generic___ffs(word) 46 #endif 47 48 #endif /* _ASM_GENERIC_BITOPS___FFS_H_ */ 49