Corentin Chary | e0e53b2 | 2011-02-04 09:06:04 +0100 | [diff] [blame] | 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 | */ |
Blue Swirl | 84803d7 | 2011-02-25 17:21:22 +0000 | [diff] [blame] | 69 | static inline unsigned long bitops_flsl(unsigned long word) |
Corentin Chary | e0e53b2 | 2011-02-04 09:06:04 +0100 | [diff] [blame] | 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); |
Corentin Chary | 04483e1 | 2011-02-24 23:47:08 +0100 | [diff] [blame] | 190 | unsigned long old = *p; |
Corentin Chary | e0e53b2 | 2011-02-04 09:06:04 +0100 | [diff] [blame] | 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 | |
Peter Maydell | 84988cf | 2012-07-06 15:48:00 +0100 | [diff] [blame] | 272 | /** |
| 273 | * extract32: |
| 274 | * @value: the value to extract the bit field from |
| 275 | * @start: the lowest bit in the bit field (numbered from 0) |
| 276 | * @length: the length of the bit field |
| 277 | * |
| 278 | * Extract from the 32 bit input @value the bit field specified by the |
| 279 | * @start and @length parameters, and return it. The bit field must |
| 280 | * lie entirely within the 32 bit word. It is valid to request that |
| 281 | * all 32 bits are returned (ie @length 32 and @start 0). |
| 282 | * |
| 283 | * Returns: the value of the bit field extracted from the input value. |
| 284 | */ |
| 285 | static inline uint32_t extract32(uint32_t value, int start, int length) |
| 286 | { |
| 287 | assert(start >= 0 && length > 0 && length <= 32 - start); |
| 288 | return (value >> start) & (~0U >> (32 - length)); |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * extract64: |
| 293 | * @value: the value to extract the bit field from |
| 294 | * @start: the lowest bit in the bit field (numbered from 0) |
| 295 | * @length: the length of the bit field |
| 296 | * |
| 297 | * Extract from the 64 bit input @value the bit field specified by the |
| 298 | * @start and @length parameters, and return it. The bit field must |
| 299 | * lie entirely within the 64 bit word. It is valid to request that |
| 300 | * all 64 bits are returned (ie @length 64 and @start 0). |
| 301 | * |
| 302 | * Returns: the value of the bit field extracted from the input value. |
| 303 | */ |
| 304 | static inline uint64_t extract64(uint64_t value, int start, int length) |
| 305 | { |
| 306 | assert(start >= 0 && length > 0 && length <= 64 - start); |
| 307 | return (value >> start) & (~0ULL >> (64 - length)); |
| 308 | } |
| 309 | |
| 310 | /** |
| 311 | * deposit32: |
| 312 | * @value: initial value to insert bit field into |
| 313 | * @start: the lowest bit in the bit field (numbered from 0) |
| 314 | * @length: the length of the bit field |
| 315 | * @fieldval: the value to insert into the bit field |
| 316 | * |
| 317 | * Deposit @fieldval into the 32 bit @value at the bit field specified |
| 318 | * by the @start and @length parameters, and return the modified |
| 319 | * @value. Bits of @value outside the bit field are not modified. |
| 320 | * Bits of @fieldval above the least significant @length bits are |
| 321 | * ignored. The bit field must lie entirely within the 32 bit word. |
Stefan Weil | ab41177 | 2012-07-08 22:31:21 +0200 | [diff] [blame] | 322 | * It is valid to request that all 32 bits are modified (ie @length |
| 323 | * 32 and @start 0). |
Peter Maydell | 84988cf | 2012-07-06 15:48:00 +0100 | [diff] [blame] | 324 | * |
| 325 | * Returns: the modified @value. |
| 326 | */ |
| 327 | static inline uint32_t deposit32(uint32_t value, int start, int length, |
| 328 | uint32_t fieldval) |
| 329 | { |
| 330 | uint32_t mask; |
| 331 | assert(start >= 0 && length > 0 && length <= 32 - start); |
| 332 | mask = (~0U >> (32 - length)) << start; |
| 333 | return (value & ~mask) | ((fieldval << start) & mask); |
| 334 | } |
| 335 | |
| 336 | /** |
Stefan Weil | ab41177 | 2012-07-08 22:31:21 +0200 | [diff] [blame] | 337 | * deposit64: |
Peter Maydell | 84988cf | 2012-07-06 15:48:00 +0100 | [diff] [blame] | 338 | * @value: initial value to insert bit field into |
| 339 | * @start: the lowest bit in the bit field (numbered from 0) |
| 340 | * @length: the length of the bit field |
| 341 | * @fieldval: the value to insert into the bit field |
| 342 | * |
| 343 | * Deposit @fieldval into the 64 bit @value at the bit field specified |
| 344 | * by the @start and @length parameters, and return the modified |
| 345 | * @value. Bits of @value outside the bit field are not modified. |
| 346 | * Bits of @fieldval above the least significant @length bits are |
Stefan Weil | ab41177 | 2012-07-08 22:31:21 +0200 | [diff] [blame] | 347 | * ignored. The bit field must lie entirely within the 64 bit word. |
Peter Maydell | 84988cf | 2012-07-06 15:48:00 +0100 | [diff] [blame] | 348 | * It is valid to request that all 64 bits are modified (ie @length |
| 349 | * 64 and @start 0). |
| 350 | * |
| 351 | * Returns: the modified @value. |
| 352 | */ |
| 353 | static inline uint64_t deposit64(uint64_t value, int start, int length, |
| 354 | uint64_t fieldval) |
| 355 | { |
| 356 | uint64_t mask; |
| 357 | assert(start >= 0 && length > 0 && length <= 64 - start); |
| 358 | mask = (~0ULL >> (64 - length)) << start; |
| 359 | return (value & ~mask) | ((fieldval << start) & mask); |
| 360 | } |
| 361 | |
Corentin Chary | e0e53b2 | 2011-02-04 09:06:04 +0100 | [diff] [blame] | 362 | #endif |