Merge branch 'for-upstream' of git://repo.or.cz/qemu/agraf
[qemu.git] / bitops.h
1 /*
2 * Bitops Module
3 *
4 * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
5 *
6 * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
7 *
8 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
9 * See the COPYING.LIB file in the top-level directory.
10 */
11
12 #ifndef BITOPS_H
13 #define BITOPS_H
14
15 #include "qemu-common.h"
16
17 #define BITS_PER_BYTE CHAR_BIT
18 #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE)
19
20 #define BIT(nr) (1UL << (nr))
21 #define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
22 #define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
23 #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
24
25 /**
26 * bitops_ffs - find first bit in word.
27 * @word: The word to search
28 *
29 * Undefined if no bit exists, so code should check against 0 first.
30 */
31 static unsigned long bitops_ffsl(unsigned long word)
32 {
33 int num = 0;
34
35 #if LONG_MAX > 0x7FFFFFFF
36 if ((word & 0xffffffff) == 0) {
37 num += 32;
38 word >>= 32;
39 }
40 #endif
41 if ((word & 0xffff) == 0) {
42 num += 16;
43 word >>= 16;
44 }
45 if ((word & 0xff) == 0) {
46 num += 8;
47 word >>= 8;
48 }
49 if ((word & 0xf) == 0) {
50 num += 4;
51 word >>= 4;
52 }
53 if ((word & 0x3) == 0) {
54 num += 2;
55 word >>= 2;
56 }
57 if ((word & 0x1) == 0) {
58 num += 1;
59 }
60 return num;
61 }
62
63 /**
64 * bitops_fls - find last (most-significant) set bit in a long word
65 * @word: the word to search
66 *
67 * Undefined if no set bit exists, so code should check against 0 first.
68 */
69 static inline unsigned long bitops_flsl(unsigned long word)
70 {
71 int num = BITS_PER_LONG - 1;
72
73 #if LONG_MAX > 0x7FFFFFFF
74 if (!(word & (~0ul << 32))) {
75 num -= 32;
76 word <<= 32;
77 }
78 #endif
79 if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
80 num -= 16;
81 word <<= 16;
82 }
83 if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
84 num -= 8;
85 word <<= 8;
86 }
87 if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
88 num -= 4;
89 word <<= 4;
90 }
91 if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
92 num -= 2;
93
94 word <<= 2;
95 }
96 if (!(word & (~0ul << (BITS_PER_LONG-1))))
97 num -= 1;
98 return num;
99 }
100
101 /**
102 * ffz - find first zero in word.
103 * @word: The word to search
104 *
105 * Undefined if no zero exists, so code should check against ~0UL first.
106 */
107 static inline unsigned long ffz(unsigned long word)
108 {
109 return bitops_ffsl(~word);
110 }
111
112 /**
113 * set_bit - Set a bit in memory
114 * @nr: the bit to set
115 * @addr: the address to start counting from
116 */
117 static inline void set_bit(int nr, volatile unsigned long *addr)
118 {
119 unsigned long mask = BIT_MASK(nr);
120 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
121
122 *p |= mask;
123 }
124
125 /**
126 * clear_bit - Clears a bit in memory
127 * @nr: Bit to clear
128 * @addr: Address to start counting from
129 */
130 static inline void clear_bit(int nr, volatile unsigned long *addr)
131 {
132 unsigned long mask = BIT_MASK(nr);
133 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
134
135 *p &= ~mask;
136 }
137
138 /**
139 * change_bit - Toggle a bit in memory
140 * @nr: Bit to change
141 * @addr: Address to start counting from
142 */
143 static inline void change_bit(int nr, volatile unsigned long *addr)
144 {
145 unsigned long mask = BIT_MASK(nr);
146 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
147
148 *p ^= mask;
149 }
150
151 /**
152 * test_and_set_bit - Set a bit and return its old value
153 * @nr: Bit to set
154 * @addr: Address to count from
155 */
156 static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
157 {
158 unsigned long mask = BIT_MASK(nr);
159 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
160 unsigned long old = *p;
161
162 *p = old | mask;
163 return (old & mask) != 0;
164 }
165
166 /**
167 * test_and_clear_bit - Clear a bit and return its old value
168 * @nr: Bit to clear
169 * @addr: Address to count from
170 */
171 static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
172 {
173 unsigned long mask = BIT_MASK(nr);
174 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
175 unsigned long old = *p;
176
177 *p = old & ~mask;
178 return (old & mask) != 0;
179 }
180
181 /**
182 * test_and_change_bit - Change a bit and return its old value
183 * @nr: Bit to change
184 * @addr: Address to count from
185 */
186 static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
187 {
188 unsigned long mask = BIT_MASK(nr);
189 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
190 unsigned long old = *p;
191
192 *p = old ^ mask;
193 return (old & mask) != 0;
194 }
195
196 /**
197 * test_bit - Determine whether a bit is set
198 * @nr: bit number to test
199 * @addr: Address to start counting from
200 */
201 static inline int test_bit(int nr, const volatile unsigned long *addr)
202 {
203 return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
204 }
205
206 /**
207 * find_last_bit - find the last set bit in a memory region
208 * @addr: The address to start the search at
209 * @size: The maximum size to search
210 *
211 * Returns the bit number of the first set bit, or size.
212 */
213 unsigned long find_last_bit(const unsigned long *addr,
214 unsigned long size);
215
216 /**
217 * find_next_bit - find the next set bit in a memory region
218 * @addr: The address to base the search on
219 * @offset: The bitnumber to start searching at
220 * @size: The bitmap size in bits
221 */
222 unsigned long find_next_bit(const unsigned long *addr,
223 unsigned long size, unsigned long offset);
224
225 /**
226 * find_next_zero_bit - find the next cleared bit in a memory region
227 * @addr: The address to base the search on
228 * @offset: The bitnumber to start searching at
229 * @size: The bitmap size in bits
230 */
231
232 unsigned long find_next_zero_bit(const unsigned long *addr,
233 unsigned long size,
234 unsigned long offset);
235
236 /**
237 * find_first_bit - find the first set bit in a memory region
238 * @addr: The address to start the search at
239 * @size: The maximum size to search
240 *
241 * Returns the bit number of the first set bit.
242 */
243 static inline unsigned long find_first_bit(const unsigned long *addr,
244 unsigned long size)
245 {
246 return find_next_bit(addr, size, 0);
247 }
248
249 /**
250 * find_first_zero_bit - find the first cleared bit in a memory region
251 * @addr: The address to start the search at
252 * @size: The maximum size to search
253 *
254 * Returns the bit number of the first cleared bit.
255 */
256 static inline unsigned long find_first_zero_bit(const unsigned long *addr,
257 unsigned long size)
258 {
259 return find_next_zero_bit(addr, size, 0);
260 }
261
262 static inline unsigned long hweight_long(unsigned long w)
263 {
264 unsigned long count;
265
266 for (count = 0; w; w >>= 1) {
267 count += w & 1;
268 }
269 return count;
270 }
271
272 #endif