bitops.h revision 7e2f4e9d384d501cf86118ebac4b8de2b86eac53 
1#ifndef _PERF_LINUX_BITOPS_H_
2#define _PERF_LINUX_BITOPS_H_
3
4#include <linux/kernel.h>
5#include <linux/compiler.h>
6#include <asm/hweight.h>
7
8#ifndef __WORDSIZE
9#define __WORDSIZE (__SIZEOF_LONG__ * 8)
10#endif
11
12#define BITS_PER_LONG __WORDSIZE
13#define BITS_PER_BYTE           8
14#define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
15#define BITS_TO_U64(nr)         DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(u64))
16#define BITS_TO_U32(nr)         DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(u32))
17#define BITS_TO_BYTES(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE)
18
19#define for_each_set_bit(bit, addr, size) \
20	for ((bit) = find_first_bit((addr), (size));		\
21	     (bit) < (size);					\
22	     (bit) = find_next_bit((addr), (size), (bit) + 1))
23
24/* same as for_each_set_bit() but use bit as value to start with */
25#define for_each_set_bit_from(bit, addr, size) \
26	for ((bit) = find_next_bit((addr), (size), (bit));	\
27	     (bit) < (size);					\
28	     (bit) = find_next_bit((addr), (size), (bit) + 1))
29
30static inline void set_bit(int nr, unsigned long *addr)
31{
32	addr[nr / BITS_PER_LONG] |= 1UL << (nr % BITS_PER_LONG);
33}
34
35static inline void clear_bit(int nr, unsigned long *addr)
36{
37	addr[nr / BITS_PER_LONG] &= ~(1UL << (nr % BITS_PER_LONG));
38}
39
40static __always_inline int test_bit(unsigned int nr, const unsigned long *addr)
41{
42	return ((1UL << (nr % BITS_PER_LONG)) &
43		(((unsigned long *)addr)[nr / BITS_PER_LONG])) != 0;
44}
45
46static inline unsigned long hweight_long(unsigned long w)
47{
48	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
49}
50
51#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
52
53/**
54 * __ffs - find first bit in word.
55 * @word: The word to search
56 *
57 * Undefined if no bit exists, so code should check against 0 first.
58 */
59static __always_inline unsigned long __ffs(unsigned long word)
60{
61	int num = 0;
62
63#if BITS_PER_LONG == 64
64	if ((word & 0xffffffff) == 0) {
65		num += 32;
66		word >>= 32;
67	}
68#endif
69	if ((word & 0xffff) == 0) {
70		num += 16;
71		word >>= 16;
72	}
73	if ((word & 0xff) == 0) {
74		num += 8;
75		word >>= 8;
76	}
77	if ((word & 0xf) == 0) {
78		num += 4;
79		word >>= 4;
80	}
81	if ((word & 0x3) == 0) {
82		num += 2;
83		word >>= 2;
84	}
85	if ((word & 0x1) == 0)
86		num += 1;
87	return num;
88}
89
90/*
91 * Find the first set bit in a memory region.
92 */
93static inline unsigned long
94find_first_bit(const unsigned long *addr, unsigned long size)
95{
96	const unsigned long *p = addr;
97	unsigned long result = 0;
98	unsigned long tmp;
99
100	while (size & ~(BITS_PER_LONG-1)) {
101		if ((tmp = *(p++)))
102			goto found;
103		result += BITS_PER_LONG;
104		size -= BITS_PER_LONG;
105	}
106	if (!size)
107		return result;
108
109	tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
110	if (tmp == 0UL)		/* Are any bits set? */
111		return result + size;	/* Nope. */
112found:
113	return result + __ffs(tmp);
114}
115
116/*
117 * Find the next set bit in a memory region.
118 */
119static inline unsigned long
120find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset)
121{
122	const unsigned long *p = addr + BITOP_WORD(offset);
123	unsigned long result = offset & ~(BITS_PER_LONG-1);
124	unsigned long tmp;
125
126	if (offset >= size)
127		return size;
128	size -= result;
129	offset %= BITS_PER_LONG;
130	if (offset) {
131		tmp = *(p++);
132		tmp &= (~0UL << offset);
133		if (size < BITS_PER_LONG)
134			goto found_first;
135		if (tmp)
136			goto found_middle;
137		size -= BITS_PER_LONG;
138		result += BITS_PER_LONG;
139	}
140	while (size & ~(BITS_PER_LONG-1)) {
141		if ((tmp = *(p++)))
142			goto found_middle;
143		result += BITS_PER_LONG;
144		size -= BITS_PER_LONG;
145	}
146	if (!size)
147		return result;
148	tmp = *p;
149
150found_first:
151	tmp &= (~0UL >> (BITS_PER_LONG - size));
152	if (tmp == 0UL)		/* Are any bits set? */
153		return result + size;	/* Nope. */
154found_middle:
155	return result + __ffs(tmp);
156}
157
158#endif
159