1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_GENERIC_BITOPS_FLS_H_
3#define _ASM_GENERIC_BITOPS_FLS_H_
4
5/**
6 * generic_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
13static __always_inline int generic_fls(unsigned 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#ifndef __HAVE_ARCH_FLS
43#define fls(x) generic_fls(x)
44#endif
45
46#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */
47