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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
136abb32 AM |
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 | ||
c8399943 | 13 | static __always_inline int fls(int x) |
136abb32 AM |
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_ */ |