1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_GENERIC_BITOPS___FFS_H_
3 #define _ASM_GENERIC_BITOPS___FFS_H_
4
5 #include <asm/types.h>
6
7 /**
8 * generic___ffs - find first bit in word.
9 * @word: The word to search
10 *
11 * Undefined if no bit exists, so code should check against 0 first.
12 */
13 static __always_inline unsigned int generic___ffs(unsigned long word)
14 {
15 unsigned int num = 0;
16
17 #if BITS_PER_LONG == 64
18 if ((word & 0xffffffff) == 0) {
19 num += 32;
20 word >>= 32;
21 }
22 #endif
23 if ((word & 0xffff) == 0) {
24 num += 16;
25 word >>= 16;
26 }
27 if ((word & 0xff) == 0) {
28 num += 8;
29 word >>= 8;
30 }
31 if ((word & 0xf) == 0) {
32 num += 4;
33 word >>= 4;
34 }
35 if ((word & 0x3) == 0) {
36 num += 2;
37 word >>= 2;
38 }
39 if ((word & 0x1) == 0)
40 num += 1;
41 return num;
42 }
43
44 #ifndef __HAVE_ARCH___FFS
45 #define __ffs(word) generic___ffs(word)
46 #endif
47
48 #endif /* _ASM_GENERIC_BITOPS___FFS_H_ */
49
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.