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