1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _ASM_GENERIC_BITOPS_FFS_H_
 3#define _ASM_GENERIC_BITOPS_FFS_H_
 4
 5/**
 6 * generic_ffs - find first bit set
 7 * @x: the word to search
 8 *
 9 * This is defined the same way as
10 * the libc and compiler builtin ffs routines, therefore
11 * differs in spirit from ffz (man ffs).
12 */
13static inline int generic_ffs(int x)
14{
15	int r = 1;
16
17	if (!x)
18		return 0;
19	if (!(x & 0xffff)) {
20		x >>= 16;
21		r += 16;
22	}
23	if (!(x & 0xff)) {
24		x >>= 8;
25		r += 8;
26	}
27	if (!(x & 0xf)) {
28		x >>= 4;
29		r += 4;
30	}
31	if (!(x & 3)) {
32		x >>= 2;
33		r += 2;
34	}
35	if (!(x & 1)) {
36		x >>= 1;
37		r += 1;
38	}
39	return r;
40}
41
42#ifndef __HAVE_ARCH_FFS
43#define ffs(x) generic_ffs(x)
44#endif
45
46#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */

 
 1#ifndef _ASM_GENERIC_BITOPS_FFS_H_
 2#define _ASM_GENERIC_BITOPS_FFS_H_
 3
 4/**
 5 * ffs - find first bit set
 6 * @x: the word to search
 7 *
 8 * This is defined the same way as
 9 * the libc and compiler builtin ffs routines, therefore
10 * differs in spirit from the above ffz (man ffs).
11 */
12static inline int ffs(int x)
13{
14	int r = 1;
15
16	if (!x)
17		return 0;
18	if (!(x & 0xffff)) {
19		x >>= 16;
20		r += 16;
21	}
22	if (!(x & 0xff)) {
23		x >>= 8;
24		r += 8;
25	}
26	if (!(x & 0xf)) {
27		x >>= 4;
28		r += 4;
29	}
30	if (!(x & 3)) {
31		x >>= 2;
32		r += 2;
33	}
34	if (!(x & 1)) {
35		x >>= 1;
36		r += 1;
37	}
38	return r;
39}
 
 
 
 
40
41#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */