1#ifndef _LINUX_BITOPS_H
2#define _LINUX_BITOPS_H
3
4
5/*
6 * ffs: find first bit set. This is defined the same way as
7 * the libc and compiler builtin ffs routines, therefore
8 * differs in spirit from the above ffz (man ffs).
9 */
10
11static inline int generic_ffs(int x)
12{
13	int r = 1;
14
15	if (!x)
16		return 0;
17	if (!(x & 0xffff)) {
18		x >>= 16;
19		r += 16;
20	}
21	if (!(x & 0xff)) {
22		x >>= 8;
23		r += 8;
24	}
25	if (!(x & 0xf)) {
26		x >>= 4;
27		r += 4;
28	}
29	if (!(x & 3)) {
30		x >>= 2;
31		r += 2;
32	}
33	if (!(x & 1)) {
34		x >>= 1;
35		r += 1;
36	}
37	return r;
38}
39
40/*
41 * hweightN: returns the hamming weight (i.e. the number
42 * of bits set) of a N-bit word
43 */
44
45static inline unsigned int generic_hweight32(unsigned int w)
46{
47        unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
48        res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
49        res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
50        res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
51        return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
52}
53
54static inline unsigned int generic_hweight16(unsigned int w)
55{
56        unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555);
57        res = (res & 0x3333) + ((res >> 2) & 0x3333);
58        res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F);
59        return (res & 0x00FF) + ((res >> 8) & 0x00FF);
60}
61
62static inline unsigned int generic_hweight8(unsigned int w)
63{
64        unsigned int res = (w & 0x55) + ((w >> 1) & 0x55);
65        res = (res & 0x33) + ((res >> 2) & 0x33);
66        return (res & 0x0F) + ((res >> 4) & 0x0F);
67}
68
69#include <asm/bitops.h>
70
71
72#endif
73