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 */
13static __always_inline unsigned long generic___ffs(unsigned long word)
14{
15	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