aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/bitops.h
blob: 48bde600a2dbcf652715d0c97b4da756ceffad3d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
#ifndef _LINUX_BITOPS_H
#define _LINUX_BITOPS_H
#include <asm/types.h>

#ifdef	__KERNEL__
#define BIT(nr)			(1UL << (nr))
#define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
#define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_LONG)
#define BITS_PER_BYTE		8
#endif

/*
 * Include this here because some architectures need generic_ffs/fls in
 * scope
 */
#include <asm/bitops.h>

#define for_each_bit(bit, addr, size) \
	for ((bit) = find_first_bit((addr), (size)); \
	     (bit) < (size); \
	     (bit) = find_next_bit((addr), (size), (bit) + 1))


static __inline__ int get_bitmask_order(unsigned int count)
{
	int order;
	
	order = fls(count);
	return order;	/* We could be slightly more clever with -1 here... */
}

static __inline__ int get_count_order(unsigned int count)
{
	int order;
	
	order = fls(count) - 1;
	if (count & (count - 1))
		order++;
	return order;
}

static inline unsigned long hweight_long(unsigned long w)
{
	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
}

/**
 * rol32 - rotate a 32-bit value left
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline __u32 rol32(__u32 word, unsigned int shift)
{
	return (word << shift) | (word >> (32 - shift));
}

/**
 * ror32 - rotate a 32-bit value right
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline __u32 ror32(__u32 word, unsigned int shift)
{
	return (word >> shift) | (word << (32 - shift));
}

/**
 * rol16 - rotate a 16-bit value left
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline __u16 rol16(__u16 word, unsigned int shift)
{
	return (word << shift) | (word >> (16 - shift));
}

/**
 * ror16 - rotate a 16-bit value right
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline __u16 ror16(__u16 word, unsigned int shift)
{
	return (word >> shift) | (word << (16 - shift));
}

/**
 * rol8 - rotate an 8-bit value left
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline __u8 rol8(__u8 word, unsigned int shift)
{
	return (word << shift) | (word >> (8 - shift));
}

/**
 * ror8 - rotate an 8-bit value right
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline __u8 ror8(__u8 word, unsigned int shift)
{
	return (word >> shift) | (word << (8 - shift));
}

static inline unsigned fls_long(unsigned long l)
{
	if (sizeof(l) == 4)
		return fls(l);
	return fls64(l);
}

#ifdef __KERNEL__
#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
extern unsigned long __find_first_bit(const unsigned long *addr,
		unsigned long size);

/**
 * find_first_bit - find the first set bit in a memory region
 * @addr: The address to start the search at
 * @size: The maximum size to search
 *
 * Returns the bit number of the first set bit.
 */
static __always_inline unsigned long
find_first_bit(const unsigned long *addr, unsigned long size)
{
	/* Avoid a function call if the bitmap size is a constant */
	/* and not bigger than BITS_PER_LONG. */

	/* insert a sentinel so that __ffs returns size if there */
	/* are no set bits in the bitmap */
	if (__builtin_constant_p(size) && (size < BITS_PER_LONG))
		return __ffs((*addr) | (1ul << size));

	/* the result of __ffs(0) is undefined, so it needs to be */
	/* handled separately */
	if (__builtin_constant_p(size) && (size == BITS_PER_LONG))
		return ((*addr) == 0) ? BITS_PER_LONG : __ffs(*addr);

	/* size is not constant or too big */
	return __find_first_bit(addr, size);
}

extern unsigned long __find_first_zero_bit(const unsigned long *addr,
		unsigned long size);

/**
 * find_first_zero_bit - find the first cleared bit in a memory region
 * @addr: The address to start the search at
 * @size: The maximum size to search
 *
 * Returns the bit number of the first cleared bit.
 */
static __always_inline unsigned long
find_first_zero_bit(const unsigned long *addr, unsigned long size)
{
	/* Avoid a function call if the bitmap size is a constant */
	/* and not bigger than BITS_PER_LONG. */

	/* insert a sentinel so that __ffs returns size if there */
	/* are no set bits in the bitmap */
	if (__builtin_constant_p(size) && (size < BITS_PER_LONG)) {
		return __ffs(~(*addr) | (1ul << size));
	}

	/* the result of __ffs(0) is undefined, so it needs to be */
	/* handled separately */
	if (__builtin_constant_p(size) && (size == BITS_PER_LONG))
		return (~(*addr) == 0) ? BITS_PER_LONG : __ffs(~(*addr));

	/* size is not constant or too big */
	return __find_first_zero_bit(addr, size);
}
#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */

#ifdef CONFIG_GENERIC_FIND_NEXT_BIT
extern unsigned long __find_next_bit(const unsigned long *addr,
		unsigned long size, unsigned long offset);

/**
 * find_next_bit - find the next set bit in a memory region
 * @addr: The address to base the search on
 * @offset: The bitnumber to start searching at
 * @size: The bitmap size in bits
 */
static __always_inline unsigned long
find_next_bit(const unsigned long *addr, unsigned long size,
		unsigned long offset)
{
	unsigned long value;

	/* Avoid a function call if the bitmap size is a constant */
	/* and not bigger than BITS_PER_LONG. */

	/* insert a sentinel so that __ffs returns size if there */
	/* are no set bits in the bitmap */
	if (__builtin_constant_p(size) && (size < BITS_PER_LONG)) {
		value = (*addr) & ((~0ul) << offset);
		value |= (1ul << size);
		return __ffs(value);
	}

	/* the result of __ffs(0) is undefined, so it needs to be */
	/* handled separately */
	if (__builtin_constant_p(size) && (size == BITS_PER_LONG)) {
		value = (*addr) & ((~0ul) << offset);
		return (value == 0) ? BITS_PER_LONG : __ffs(value);
	}

	/* size is not constant or too big */
	return __find_next_bit(addr, size, offset);
}

extern unsigned long __find_next_zero_bit(const unsigned long *addr,
		unsigned long size, unsigned long offset);

/**
 * find_next_zero_bit - find the next cleared bit in a memory region
 * @addr: The address to base the search on
 * @offset: The bitnumber to start searching at
 * @size: The bitmap size in bits
 */
static __always_inline unsigned long
find_next_zero_bit(const unsigned long *addr, unsigned long size,
		unsigned long offset)
{
	unsigned long value;

	/* Avoid a function call if the bitmap size is a constant */
	/* and not bigger than BITS_PER_LONG. */

	/* insert a sentinel so that __ffs returns size if there */
	/* are no set bits in the bitmap */
	if (__builtin_constant_p(size) && (size < BITS_PER_LONG)) {
		value = (~(*addr)) & ((~0ul) << offset);
		value |= (1ul << size);
		return __ffs(value);
	}

	/* the result of __ffs(0) is undefined, so it needs to be */
	/* handled separately */
	if (__builtin_constant_p(size) && (size == BITS_PER_LONG)) {
		value = (~(*addr)) & ((~0ul) << offset);
		return (value == 0) ? BITS_PER_LONG : __ffs(value);
	}

	/* size is not constant or too big */
	return __find_next_zero_bit(addr, size, offset);
}
#endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
#endif /* __KERNEL__ */
#endif