include/qemu/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 #include "host-utils.h"
  17
  18 #define BITS_PER_BYTE           CHAR_BIT
  19 #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
  20
  21 #define BIT(nr)                 (1UL << (nr))
  22 #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
  23 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  24 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  25
  26 /**
  27  * set_bit - Set a bit in memory
  28  * @nr: the bit to set
  29  * @addr: the address to start counting from
  30  */
  31 static inline void set_bit(int nr, unsigned long *addr)
  32 {
  33         unsigned long mask = BIT_MASK(nr);
  34         unsigned long *p = addr + BIT_WORD(nr);
  35
  36         *p  |= mask;
  37 }
  38
  39 /**
  40  * clear_bit - Clears a bit in memory
  41  * @nr: Bit to clear
  42  * @addr: Address to start counting from
  43  */
  44 static inline void clear_bit(int nr, unsigned long *addr)
  45 {
  46         unsigned long mask = BIT_MASK(nr);
  47         unsigned long *p = addr + BIT_WORD(nr);
  48
  49         *p &= ~mask;
  50 }
  51
  52 /**
  53  * change_bit - Toggle a bit in memory
  54  * @nr: Bit to change
  55  * @addr: Address to start counting from
  56  */
  57 static inline void change_bit(int nr, unsigned long *addr)
  58 {
  59         unsigned long mask = BIT_MASK(nr);
  60         unsigned long *p = addr + BIT_WORD(nr);
  61
  62         *p ^= mask;
  63 }
  64
  65 /**
  66  * test_and_set_bit - Set a bit and return its old value
  67  * @nr: Bit to set
  68  * @addr: Address to count from
  69  */
  70 static inline int test_and_set_bit(int nr, unsigned long *addr)
  71 {
  72         unsigned long mask = BIT_MASK(nr);
  73         unsigned long *p = addr + BIT_WORD(nr);
  74         unsigned long old = *p;
  75
  76         *p = old | mask;
  77         return (old & mask) != 0;
  78 }
  79
  80 /**
  81  * test_and_clear_bit - Clear a bit and return its old value
  82  * @nr: Bit to clear
  83  * @addr: Address to count from
  84  */
  85 static inline int test_and_clear_bit(int nr, unsigned long *addr)
  86 {
  87         unsigned long mask = BIT_MASK(nr);
  88         unsigned long *p = addr + BIT_WORD(nr);
  89         unsigned long old = *p;
  90
  91         *p = old & ~mask;
  92         return (old & mask) != 0;
  93 }
  94
  95 /**
  96  * test_and_change_bit - Change a bit and return its old value
  97  * @nr: Bit to change
  98  * @addr: Address to count from
  99  */
 100 static inline int test_and_change_bit(int nr, unsigned long *addr)
 101 {
 102         unsigned long mask = BIT_MASK(nr);
 103         unsigned long *p = addr + BIT_WORD(nr);
 104         unsigned long old = *p;
 105
 106         *p = old ^ mask;
 107         return (old & mask) != 0;
 108 }
 109
 110 /**
 111  * test_bit - Determine whether a bit is set
 112  * @nr: bit number to test
 113  * @addr: Address to start counting from
 114  */
 115 static inline int test_bit(int nr, const unsigned long *addr)
 116 {
 117         return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
 118 }
 119
 120 /**
 121  * find_last_bit - find the last set bit in a memory region
 122  * @addr: The address to start the search at
 123  * @size: The maximum size to search
 124  *
 125  * Returns the bit number of the first set bit, or size.
 126  */
 127 unsigned long find_last_bit(const unsigned long *addr,
 128                             unsigned long size);
 129
 130 /**
 131  * find_next_bit - find the next set bit in a memory region
 132  * @addr: The address to base the search on
 133  * @offset: The bitnumber to start searching at
 134  * @size: The bitmap size in bits
 135  */
 136 unsigned long find_next_bit(const unsigned long *addr,
 137                                    unsigned long size, unsigned long offset);
 138
 139 /**
 140  * find_next_zero_bit - find the next cleared bit in a memory region
 141  * @addr: The address to base the search on
 142  * @offset: The bitnumber to start searching at
 143  * @size: The bitmap size in bits
 144  */
 145
 146 unsigned long find_next_zero_bit(const unsigned long *addr,
 147                                  unsigned long size,
 148                                  unsigned long offset);
 149
 150 /**
 151  * find_first_bit - find the first set bit in a memory region
 152  * @addr: The address to start the search at
 153  * @size: The maximum size to search
 154  *
 155  * Returns the bit number of the first set bit.
 156  */
 157 static inline unsigned long find_first_bit(const unsigned long *addr,
 158                                            unsigned long size)
 159 {
 160     return find_next_bit(addr, size, 0);
 161 }
 162
 163 /**
 164  * find_first_zero_bit - find the first cleared bit in a memory region
 165  * @addr: The address to start the search at
 166  * @size: The maximum size to search
 167  *
 168  * Returns the bit number of the first cleared bit.
 169  */
 170 static inline unsigned long find_first_zero_bit(const unsigned long *addr,
 171                                                 unsigned long size)
 172 {
 173     return find_next_zero_bit(addr, size, 0);
 174 }
 175
 176 static inline unsigned long hweight_long(unsigned long w)
 177 {
 178     unsigned long count;
 179
 180     for (count = 0; w; w >>= 1) {
 181         count += w & 1;
 182     }
 183     return count;
 184 }
 185
 186 /**
 187  * rol8 - rotate an 8-bit value left
 188  * @word: value to rotate
 189  * @shift: bits to roll
 190  */
 191 static inline uint8_t rol8(uint8_t word, unsigned int shift)
 192 {
 193     return (word << shift) | (word >> (8 - shift));
 194 }
 195
 196 /**
 197  * ror8 - rotate an 8-bit value right
 198  * @word: value to rotate
 199  * @shift: bits to roll
 200  */
 201 static inline uint8_t ror8(uint8_t word, unsigned int shift)
 202 {
 203     return (word >> shift) | (word << (8 - shift));
 204 }
 205
 206 /**
 207  * rol16 - rotate a 16-bit value left
 208  * @word: value to rotate
 209  * @shift: bits to roll
 210  */
 211 static inline uint16_t rol16(uint16_t word, unsigned int shift)
 212 {
 213     return (word << shift) | (word >> (16 - shift));
 214 }
 215
 216 /**
 217  * ror16 - rotate a 16-bit value right
 218  * @word: value to rotate
 219  * @shift: bits to roll
 220  */
 221 static inline uint16_t ror16(uint16_t word, unsigned int shift)
 222 {
 223     return (word >> shift) | (word << (16 - shift));
 224 }
 225
 226 /**
 227  * rol32 - rotate a 32-bit value left
 228  * @word: value to rotate
 229  * @shift: bits to roll
 230  */
 231 static inline uint32_t rol32(uint32_t word, unsigned int shift)
 232 {
 233     return (word << shift) | (word >> (32 - shift));
 234 }
 235
 236 /**
 237  * ror32 - rotate a 32-bit value right
 238  * @word: value to rotate
 239  * @shift: bits to roll
 240  */
 241 static inline uint32_t ror32(uint32_t word, unsigned int shift)
 242 {
 243     return (word >> shift) | (word << (32 - shift));
 244 }
 245
 246 /**
 247  * rol64 - rotate a 64-bit value left
 248  * @word: value to rotate
 249  * @shift: bits to roll
 250  */
 251 static inline uint64_t rol64(uint64_t word, unsigned int shift)
 252 {
 253     return (word << shift) | (word >> (64 - shift));
 254 }
 255
 256 /**
 257  * ror64 - rotate a 64-bit value right
 258  * @word: value to rotate
 259  * @shift: bits to roll
 260  */
 261 static inline uint64_t ror64(uint64_t word, unsigned int shift)
 262 {
 263     return (word >> shift) | (word << (64 - shift));
 264 }
 265
 266 /**
 267  * extract32:
 268  * @value: the value to extract the bit field from
 269  * @start: the lowest bit in the bit field (numbered from 0)
 270  * @length: the length of the bit field
 271  *
 272  * Extract from the 32 bit input @value the bit field specified by the
 273  * @start and @length parameters, and return it. The bit field must
 274  * lie entirely within the 32 bit word. It is valid to request that
 275  * all 32 bits are returned (ie @length 32 and @start 0).
 276  *
 277  * Returns: the value of the bit field extracted from the input value.
 278  */
 279 static inline uint32_t extract32(uint32_t value, int start, int length)
 280 {
 281     assert(start >= 0 && length > 0 && length <= 32 - start);
 282     return (value >> start) & (~0U >> (32 - length));
 283 }
 284
 285 /**
 286  * extract64:
 287  * @value: the value to extract the bit field from
 288  * @start: the lowest bit in the bit field (numbered from 0)
 289  * @length: the length of the bit field
 290  *
 291  * Extract from the 64 bit input @value the bit field specified by the
 292  * @start and @length parameters, and return it. The bit field must
 293  * lie entirely within the 64 bit word. It is valid to request that
 294  * all 64 bits are returned (ie @length 64 and @start 0).
 295  *
 296  * Returns: the value of the bit field extracted from the input value.
 297  */
 298 static inline uint64_t extract64(uint64_t value, int start, int length)
 299 {
 300     assert(start >= 0 && length > 0 && length <= 64 - start);
 301     return (value >> start) & (~0ULL >> (64 - length));
 302 }
 303
 304 /**
 305  * sextract32:
 306  * @value: the value to extract the bit field from
 307  * @start: the lowest bit in the bit field (numbered from 0)
 308  * @length: the length of the bit field
 309  *
 310  * Extract from the 32 bit input @value the bit field specified by the
 311  * @start and @length parameters, and return it, sign extended to
 312  * an int32_t (ie with the most significant bit of the field propagated
 313  * to all the upper bits of the return value). The bit field must lie
 314  * entirely within the 32 bit word. It is valid to request that
 315  * all 32 bits are returned (ie @length 32 and @start 0).
 316  *
 317  * Returns: the sign extended value of the bit field extracted from the
 318  * input value.
 319  */
 320 static inline int32_t sextract32(uint32_t value, int start, int length)
 321 {
 322     assert(start >= 0 && length > 0 && length <= 32 - start);
 323     /* Note that this implementation relies on right shift of signed
 324      * integers being an arithmetic shift.
 325      */
 326     return ((int32_t)(value << (32 - length - start))) >> (32 - length);
 327 }
 328
 329 /**
 330  * sextract64:
 331  * @value: the value to extract the bit field from
 332  * @start: the lowest bit in the bit field (numbered from 0)
 333  * @length: the length of the bit field
 334  *
 335  * Extract from the 64 bit input @value the bit field specified by the
 336  * @start and @length parameters, and return it, sign extended to
 337  * an int64_t (ie with the most significant bit of the field propagated
 338  * to all the upper bits of the return value). The bit field must lie
 339  * entirely within the 64 bit word. It is valid to request that
 340  * all 64 bits are returned (ie @length 64 and @start 0).
 341  *
 342  * Returns: the sign extended value of the bit field extracted from the
 343  * input value.
 344  */
 345 static inline uint64_t sextract64(uint64_t value, int start, int length)
 346 {
 347     assert(start >= 0 && length > 0 && length <= 64 - start);
 348     /* Note that this implementation relies on right shift of signed
 349      * integers being an arithmetic shift.
 350      */
 351     return ((int64_t)(value << (64 - length - start))) >> (64 - length);
 352 }
 353
 354 /**
 355  * deposit32:
 356  * @value: initial value to insert bit field into
 357  * @start: the lowest bit in the bit field (numbered from 0)
 358  * @length: the length of the bit field
 359  * @fieldval: the value to insert into the bit field
 360  *
 361  * Deposit @fieldval into the 32 bit @value at the bit field specified
 362  * by the @start and @length parameters, and return the modified
 363  * @value. Bits of @value outside the bit field are not modified.
 364  * Bits of @fieldval above the least significant @length bits are
 365  * ignored. The bit field must lie entirely within the 32 bit word.
 366  * It is valid to request that all 32 bits are modified (ie @length
 367  * 32 and @start 0).
 368  *
 369  * Returns: the modified @value.
 370  */
 371 static inline uint32_t deposit32(uint32_t value, int start, int length,
 372                                  uint32_t fieldval)
 373 {
 374     uint32_t mask;
 375     assert(start >= 0 && length > 0 && length <= 32 - start);
 376     mask = (~0U >> (32 - length)) << start;
 377     return (value & ~mask) | ((fieldval << start) & mask);
 378 }
 379
 380 /**
 381  * deposit64:
 382  * @value: initial value to insert bit field into
 383  * @start: the lowest bit in the bit field (numbered from 0)
 384  * @length: the length of the bit field
 385  * @fieldval: the value to insert into the bit field
 386  *
 387  * Deposit @fieldval into the 64 bit @value at the bit field specified
 388  * by the @start and @length parameters, and return the modified
 389  * @value. Bits of @value outside the bit field are not modified.
 390  * Bits of @fieldval above the least significant @length bits are
 391  * ignored. The bit field must lie entirely within the 64 bit word.
 392  * It is valid to request that all 64 bits are modified (ie @length
 393  * 64 and @start 0).
 394  *
 395  * Returns: the modified @value.
 396  */
 397 static inline uint64_t deposit64(uint64_t value, int start, int length,
 398                                  uint64_t fieldval)
 399 {
 400     uint64_t mask;
 401     assert(start >= 0 && length > 0 && length <= 64 - start);
 402     mask = (~0ULL >> (64 - length)) << start;
 403     return (value & ~mask) | ((fieldval << start) & mask);
 404 }
 405
 406 #endif