xref: /linux/include/asm-generic/bitops/builtin-__fls.h (revision 6e7fd890f1d6ac83805409e9c346240de2705584)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_GENERIC_BITOPS_BUILTIN___FLS_H_
3 #define _ASM_GENERIC_BITOPS_BUILTIN___FLS_H_
4 
5 /**
6  * __fls - find last (most-significant) set bit in a long word
7  * @word: the word to search
8  *
9  * Undefined if no set bit exists, so code should check against 0 first.
10  */
11 static __always_inline unsigned int __fls(unsigned long word)
12 {
13 	return (sizeof(word) * 8) - 1 - __builtin_clzl(word);
14 }
15 
16 #endif
17