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