aboutsummaryrefslogtreecommitdiff
path: root/include/qemu/bitops.h
blob: 1881284cb5f3434306e79a0eadc69392c1020f9d (plain)
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
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
/*
 * Bitops Module
 *
 * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
 *
 * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
 *
 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
 * See the COPYING.LIB file in the top-level directory.
 */

#ifndef BITOPS_H
#define BITOPS_H


#include "host-utils.h"
#include "atomic.h"

#define BITS_PER_BYTE           CHAR_BIT
#define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)

#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_BYTE * sizeof(long))

#define MAKE_64BIT_MASK(shift, length) \
    (((~0ULL) >> (64 - (length))) << (shift))

/**
 * set_bit - Set a bit in memory
 * @nr: the bit to set
 * @addr: the address to start counting from
 */
static inline void set_bit(long nr, unsigned long *addr)
{
    unsigned long mask = BIT_MASK(nr);
    unsigned long *p = addr + BIT_WORD(nr);

    *p  |= mask;
}

/**
 * set_bit_atomic - Set a bit in memory atomically
 * @nr: the bit to set
 * @addr: the address to start counting from
 */
static inline void set_bit_atomic(long nr, unsigned long *addr)
{
    unsigned long mask = BIT_MASK(nr);
    unsigned long *p = addr + BIT_WORD(nr);

    atomic_or(p, mask);
}

/**
 * clear_bit - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 */
static inline void clear_bit(long nr, unsigned long *addr)
{
    unsigned long mask = BIT_MASK(nr);
    unsigned long *p = addr + BIT_WORD(nr);

    *p &= ~mask;
}

/**
 * change_bit - Toggle a bit in memory
 * @nr: Bit to change
 * @addr: Address to start counting from
 */
static inline void change_bit(long nr, unsigned long *addr)
{
    unsigned long mask = BIT_MASK(nr);
    unsigned long *p = addr + BIT_WORD(nr);

    *p ^= mask;
}

/**
 * test_and_set_bit - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 */
static inline int test_and_set_bit(long nr, unsigned long *addr)
{
    unsigned long mask = BIT_MASK(nr);
    unsigned long *p = addr + BIT_WORD(nr);
    unsigned long old = *p;

    *p = old | mask;
    return (old & mask) != 0;
}

/**
 * test_and_clear_bit - Clear a bit and return its old value
 * @nr: Bit to clear
 * @addr: Address to count from
 */
static inline int test_and_clear_bit(long nr, unsigned long *addr)
{
    unsigned long mask = BIT_MASK(nr);
    unsigned long *p = addr + BIT_WORD(nr);
    unsigned long old = *p;

    *p = old & ~mask;
    return (old & mask) != 0;
}

/**
 * test_and_change_bit - Change a bit and return its old value
 * @nr: Bit to change
 * @addr: Address to count from
 */
static inline int test_and_change_bit(long nr, unsigned long *addr)
{
    unsigned long mask = BIT_MASK(nr);
    unsigned long *p = addr + BIT_WORD(nr);
    unsigned long old = *p;

    *p = old ^ mask;
    return (old & mask) != 0;
}

/**
 * test_bit - Determine whether a bit is set
 * @nr: bit number to test
 * @addr: Address to start counting from
 */
static inline int test_bit(long nr, const unsigned long *addr)
{
    return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
}

/**
 * find_last_bit - find the last 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, or size.
 */
unsigned long find_last_bit(const unsigned long *addr,
                            unsigned long size);

/**
 * 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
 */
unsigned long find_next_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
 */

unsigned long find_next_zero_bit(const unsigned long *addr,
                                 unsigned long size,
                                 unsigned long offset);

/**
 * 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 inline unsigned long find_first_bit(const unsigned long *addr,
                                           unsigned long size)
{
    unsigned long result, tmp;

    for (result = 0; result < size; result += BITS_PER_LONG) {
        tmp = *addr++;
        if (tmp) {
            result += ctzl(tmp);
            return result < size ? result : size;
        }
    }
    /* Not found */
    return 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 inline unsigned long find_first_zero_bit(const unsigned long *addr,
                                                unsigned long size)
{
    return find_next_zero_bit(addr, size, 0);
}

static inline unsigned long hweight_long(unsigned long w)
{
    unsigned long count;

    for (count = 0; w; w >>= 1) {
        count += w & 1;
    }
    return count;
}

/**
 * rol8 - rotate an 8-bit value left
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint8_t rol8(uint8_t word, unsigned int shift)
{
    return (word << shift) | (word >> ((8 - shift) & 7));
}

/**
 * ror8 - rotate an 8-bit value right
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint8_t ror8(uint8_t word, unsigned int shift)
{
    return (word >> shift) | (word << ((8 - shift) & 7));
}

/**
 * rol16 - rotate a 16-bit value left
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint16_t rol16(uint16_t word, unsigned int shift)
{
    return (word << shift) | (word >> ((16 - shift) & 15));
}

/**
 * ror16 - rotate a 16-bit value right
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint16_t ror16(uint16_t word, unsigned int shift)
{
    return (word >> shift) | (word << ((16 - shift) & 15));
}

/**
 * rol32 - rotate a 32-bit value left
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint32_t rol32(uint32_t word, unsigned int shift)
{
    return (word << shift) | (word >> ((32 - shift) & 31));
}

/**
 * ror32 - rotate a 32-bit value right
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint32_t ror32(uint32_t word, unsigned int shift)
{
    return (word >> shift) | (word << ((32 - shift) & 31));
}

/**
 * rol64 - rotate a 64-bit value left
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint64_t rol64(uint64_t word, unsigned int shift)
{
    return (word << shift) | (word >> ((64 - shift) & 63));
}

/**
 * ror64 - rotate a 64-bit value right
 * @word: value to rotate
 * @shift: bits to roll
 */
static inline uint64_t ror64(uint64_t word, unsigned int shift)
{
    return (word >> shift) | (word << ((64 - shift) & 63));
}

/**
 * extract32:
 * @value: the value to extract the bit field from
 * @start: the lowest bit in the bit field (numbered from 0)
 * @length: the length of the bit field
 *
 * Extract from the 32 bit input @value the bit field specified by the
 * @start and @length parameters, and return it. The bit field must
 * lie entirely within the 32 bit word. It is valid to request that
 * all 32 bits are returned (ie @length 32 and @start 0).
 *
 * Returns: the value of the bit field extracted from the input value.
 */
static inline uint32_t extract32(uint32_t value, int start, int length)
{
    assert(start >= 0 && length > 0 && length <= 32 - start);
    return (value >> start) & (~0U >> (32 - length));
}

/**
 * extract64:
 * @value: the value to extract the bit field from
 * @start: the lowest bit in the bit field (numbered from 0)
 * @length: the length of the bit field
 *
 * Extract from the 64 bit input @value the bit field specified by the
 * @start and @length parameters, and return it. The bit field must
 * lie entirely within the 64 bit word. It is valid to request that
 * all 64 bits are returned (ie @length 64 and @start 0).
 *
 * Returns: the value of the bit field extracted from the input value.
 */
static inline uint64_t extract64(uint64_t value, int start, int length)
{
    assert(start >= 0 && length > 0 && length <= 64 - start);
    return (value >> start) & (~0ULL >> (64 - length));
}

/**
 * sextract32:
 * @value: the value to extract the bit field from
 * @start: the lowest bit in the bit field (numbered from 0)
 * @length: the length of the bit field
 *
 * Extract from the 32 bit input @value the bit field specified by the
 * @start and @length parameters, and return it, sign extended to
 * an int32_t (ie with the most significant bit of the field propagated
 * to all the upper bits of the return value). The bit field must lie
 * entirely within the 32 bit word. It is valid to request that
 * all 32 bits are returned (ie @length 32 and @start 0).
 *
 * Returns: the sign extended value of the bit field extracted from the
 * input value.
 */
static inline int32_t sextract32(uint32_t value, int start, int length)
{
    assert(start >= 0 && length > 0 && length <= 32 - start);
    /* Note that this implementation relies on right shift of signed
     * integers being an arithmetic shift.
     */
    return ((int32_t)(value << (32 - length - start))) >> (32 - length);
}

/**
 * sextract64:
 * @value: the value to extract the bit field from
 * @start: the lowest bit in the bit field (numbered from 0)
 * @length: the length of the bit field
 *
 * Extract from the 64 bit input @value the bit field specified by the
 * @start and @length parameters, and return it, sign extended to
 * an int64_t (ie with the most significant bit of the field propagated
 * to all the upper bits of the return value). The bit field must lie
 * entirely within the 64 bit word. It is valid to request that
 * all 64 bits are returned (ie @length 64 and @start 0).
 *
 * Returns: the sign extended value of the bit field extracted from the
 * input value.
 */
static inline int64_t sextract64(uint64_t value, int start, int length)
{
    assert(start >= 0 && length > 0 && length <= 64 - start);
    /* Note that this implementation relies on right shift of signed
     * integers being an arithmetic shift.
     */
    return ((int64_t)(value << (64 - length - start))) >> (64 - length);
}

/**
 * deposit32:
 * @value: initial value to insert bit field into
 * @start: the lowest bit in the bit field (numbered from 0)
 * @length: the length of the bit field
 * @fieldval: the value to insert into the bit field
 *
 * Deposit @fieldval into the 32 bit @value at the bit field specified
 * by the @start and @length parameters, and return the modified
 * @value. Bits of @value outside the bit field are not modified.
 * Bits of @fieldval above the least significant @length bits are
 * ignored. The bit field must lie entirely within the 32 bit word.
 * It is valid to request that all 32 bits are modified (ie @length
 * 32 and @start 0).
 *
 * Returns: the modified @value.
 */
static inline uint32_t deposit32(uint32_t value, int start, int length,
                                 uint32_t fieldval)
{
    uint32_t mask;
    assert(start >= 0 && length > 0 && length <= 32 - start);
    mask = (~0U >> (32 - length)) << start;
    return (value & ~mask) | ((fieldval << start) & mask);
}

/**
 * deposit64:
 * @value: initial value to insert bit field into
 * @start: the lowest bit in the bit field (numbered from 0)
 * @length: the length of the bit field
 * @fieldval: the value to insert into the bit field
 *
 * Deposit @fieldval into the 64 bit @value at the bit field specified
 * by the @start and @length parameters, and return the modified
 * @value. Bits of @value outside the bit field are not modified.
 * Bits of @fieldval above the least significant @length bits are
 * ignored. The bit field must lie entirely within the 64 bit word.
 * It is valid to request that all 64 bits are modified (ie @length
 * 64 and @start 0).
 *
 * Returns: the modified @value.
 */
static inline uint64_t deposit64(uint64_t value, int start, int length,
                                 uint64_t fieldval)
{
    uint64_t mask;
    assert(start >= 0 && length > 0 && length <= 64 - start);
    mask = (~0ULL >> (64 - length)) << start;
    return (value & ~mask) | ((fieldval << start) & mask);
}

/**
 * half_shuffle32:
 * @value: 32-bit value (of which only the bottom 16 bits are of interest)
 *
 * Given an input value:
 *  xxxx xxxx xxxx xxxx ABCD EFGH IJKL MNOP
 * return the value where the bottom 16 bits are spread out into
 * the odd bits in the word, and the even bits are zeroed:
 *  0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N 0O0P
 *
 * Any bits set in the top half of the input are ignored.
 *
 * Returns: the shuffled bits.
 */
static inline uint32_t half_shuffle32(uint32_t x)
{
    /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
     * It ignores any bits set in the top half of the input.
     */
    x = ((x & 0xFF00) << 8) | (x & 0x00FF);
    x = ((x << 4) | x) & 0x0F0F0F0F;
    x = ((x << 2) | x) & 0x33333333;
    x = ((x << 1) | x) & 0x55555555;
    return x;
}

/**
 * half_shuffle64:
 * @value: 64-bit value (of which only the bottom 32 bits are of interest)
 *
 * Given an input value:
 *  xxxx xxxx xxxx .... xxxx xxxx ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
 * return the value where the bottom 32 bits are spread out into
 * the odd bits in the word, and the even bits are zeroed:
 *  0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N .... 0U0V 0W0X 0Y0Z 0a0b 0c0d 0e0f
 *
 * Any bits set in the top half of the input are ignored.
 *
 * Returns: the shuffled bits.
 */
static inline uint64_t half_shuffle64(uint64_t x)
{
    /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
     * It ignores any bits set in the top half of the input.
     */
    x = ((x & 0xFFFF0000ULL) << 16) | (x & 0xFFFF);
    x = ((x << 8) | x) & 0x00FF00FF00FF00FFULL;
    x = ((x << 4) | x) & 0x0F0F0F0F0F0F0F0FULL;
    x = ((x << 2) | x) & 0x3333333333333333ULL;
    x = ((x << 1) | x) & 0x5555555555555555ULL;
    return x;
}

/**
 * half_unshuffle32:
 * @value: 32-bit value (of which only the odd bits are of interest)
 *
 * Given an input value:
 *  xAxB xCxD xExF xGxH xIxJ xKxL xMxN xOxP
 * return the value where all the odd bits are compressed down
 * into the low half of the word, and the high half is zeroed:
 *  0000 0000 0000 0000 ABCD EFGH IJKL MNOP
 *
 * Any even bits set in the input are ignored.
 *
 * Returns: the unshuffled bits.
 */
static inline uint32_t half_unshuffle32(uint32_t x)
{
    /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
     * where it is called an inverse half shuffle.
     */
    x &= 0x55555555;
    x = ((x >> 1) | x) & 0x33333333;
    x = ((x >> 2) | x) & 0x0F0F0F0F;
    x = ((x >> 4) | x) & 0x00FF00FF;
    x = ((x >> 8) | x) & 0x0000FFFF;
    return x;
}

/**
 * half_unshuffle64:
 * @value: 64-bit value (of which only the odd bits are of interest)
 *
 * Given an input value:
 *  xAxB xCxD xExF xGxH xIxJ xKxL xMxN .... xUxV xWxX xYxZ xaxb xcxd xexf
 * return the value where all the odd bits are compressed down
 * into the low half of the word, and the high half is zeroed:
 *  0000 0000 0000 .... 0000 0000 ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
 *
 * Any even bits set in the input are ignored.
 *
 * Returns: the unshuffled bits.
 */
static inline uint64_t half_unshuffle64(uint64_t x)
{
    /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
     * where it is called an inverse half shuffle.
     */
    x &= 0x5555555555555555ULL;
    x = ((x >> 1) | x) & 0x3333333333333333ULL;
    x = ((x >> 2) | x) & 0x0F0F0F0F0F0F0F0FULL;
    x = ((x >> 4) | x) & 0x00FF00FF00FF00FFULL;
    x = ((x >> 8) | x) & 0x0000FFFF0000FFFFULL;
    x = ((x >> 16) | x) & 0x00000000FFFFFFFFULL;
    return x;
}

#endif