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