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 | |
16 | #include "host-utils.h" |
17 | #include "atomic.h" |
18 | |
19 | #define BITS_PER_BYTE CHAR_BIT |
20 | #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE) |
21 | |
22 | #define BIT(nr) (1UL << (nr)) |
23 | #define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) |
24 | #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) |
25 | #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) |
26 | |
27 | #define MAKE_64BIT_MASK(shift, length) \ |
28 | (((~0ULL) >> (64 - (length))) << (shift)) |
29 | |
30 | /** |
31 | * set_bit - Set a bit in memory |
32 | * @nr: the bit to set |
33 | * @addr: the address to start counting from |
34 | */ |
35 | static inline void set_bit(long nr, unsigned long *addr) |
36 | { |
37 | unsigned long mask = BIT_MASK(nr); |
38 | unsigned long *p = addr + BIT_WORD(nr); |
39 | |
40 | *p |= mask; |
41 | } |
42 | |
43 | /** |
44 | * set_bit_atomic - Set a bit in memory atomically |
45 | * @nr: the bit to set |
46 | * @addr: the address to start counting from |
47 | */ |
48 | static inline void set_bit_atomic(long nr, unsigned long *addr) |
49 | { |
50 | unsigned long mask = BIT_MASK(nr); |
51 | unsigned long *p = addr + BIT_WORD(nr); |
52 | |
53 | atomic_or(p, mask); |
54 | } |
55 | |
56 | /** |
57 | * clear_bit - Clears a bit in memory |
58 | * @nr: Bit to clear |
59 | * @addr: Address to start counting from |
60 | */ |
61 | static inline void clear_bit(long nr, unsigned long *addr) |
62 | { |
63 | unsigned long mask = BIT_MASK(nr); |
64 | unsigned long *p = addr + BIT_WORD(nr); |
65 | |
66 | *p &= ~mask; |
67 | } |
68 | |
69 | /** |
70 | * change_bit - Toggle a bit in memory |
71 | * @nr: Bit to change |
72 | * @addr: Address to start counting from |
73 | */ |
74 | static inline void change_bit(long nr, unsigned long *addr) |
75 | { |
76 | unsigned long mask = BIT_MASK(nr); |
77 | unsigned long *p = addr + BIT_WORD(nr); |
78 | |
79 | *p ^= mask; |
80 | } |
81 | |
82 | /** |
83 | * test_and_set_bit - Set a bit and return its old value |
84 | * @nr: Bit to set |
85 | * @addr: Address to count from |
86 | */ |
87 | static inline int test_and_set_bit(long nr, unsigned long *addr) |
88 | { |
89 | unsigned long mask = BIT_MASK(nr); |
90 | unsigned long *p = addr + BIT_WORD(nr); |
91 | unsigned long old = *p; |
92 | |
93 | *p = old | mask; |
94 | return (old & mask) != 0; |
95 | } |
96 | |
97 | /** |
98 | * test_and_clear_bit - Clear a bit and return its old value |
99 | * @nr: Bit to clear |
100 | * @addr: Address to count from |
101 | */ |
102 | static inline int test_and_clear_bit(long nr, unsigned long *addr) |
103 | { |
104 | unsigned long mask = BIT_MASK(nr); |
105 | unsigned long *p = addr + BIT_WORD(nr); |
106 | unsigned long old = *p; |
107 | |
108 | *p = old & ~mask; |
109 | return (old & mask) != 0; |
110 | } |
111 | |
112 | /** |
113 | * test_and_change_bit - Change a bit and return its old value |
114 | * @nr: Bit to change |
115 | * @addr: Address to count from |
116 | */ |
117 | static inline int test_and_change_bit(long nr, unsigned long *addr) |
118 | { |
119 | unsigned long mask = BIT_MASK(nr); |
120 | unsigned long *p = addr + BIT_WORD(nr); |
121 | unsigned long old = *p; |
122 | |
123 | *p = old ^ mask; |
124 | return (old & mask) != 0; |
125 | } |
126 | |
127 | /** |
128 | * test_bit - Determine whether a bit is set |
129 | * @nr: bit number to test |
130 | * @addr: Address to start counting from |
131 | */ |
132 | static inline int test_bit(long nr, const unsigned long *addr) |
133 | { |
134 | return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); |
135 | } |
136 | |
137 | /** |
138 | * find_last_bit - find the last set bit in a memory region |
139 | * @addr: The address to start the search at |
140 | * @size: The maximum size to search |
141 | * |
142 | * Returns the bit number of the first set bit, or size. |
143 | */ |
144 | unsigned long find_last_bit(const unsigned long *addr, |
145 | unsigned long size); |
146 | |
147 | /** |
148 | * find_next_bit - find the next set bit in a memory region |
149 | * @addr: The address to base the search on |
150 | * @offset: The bitnumber to start searching at |
151 | * @size: The bitmap size in bits |
152 | */ |
153 | unsigned long find_next_bit(const unsigned long *addr, |
154 | unsigned long size, |
155 | unsigned long offset); |
156 | |
157 | /** |
158 | * find_next_zero_bit - find the next cleared bit in a memory region |
159 | * @addr: The address to base the search on |
160 | * @offset: The bitnumber to start searching at |
161 | * @size: The bitmap size in bits |
162 | */ |
163 | |
164 | unsigned long find_next_zero_bit(const unsigned long *addr, |
165 | unsigned long size, |
166 | unsigned long offset); |
167 | |
168 | /** |
169 | * find_first_bit - find the first set bit in a memory region |
170 | * @addr: The address to start the search at |
171 | * @size: The maximum size to search |
172 | * |
173 | * Returns the bit number of the first set bit. |
174 | */ |
175 | static inline unsigned long find_first_bit(const unsigned long *addr, |
176 | unsigned long size) |
177 | { |
178 | unsigned long result, tmp; |
179 | |
180 | for (result = 0; result < size; result += BITS_PER_LONG) { |
181 | tmp = *addr++; |
182 | if (tmp) { |
183 | result += ctzl(tmp); |
184 | return result < size ? result : size; |
185 | } |
186 | } |
187 | /* Not found */ |
188 | return size; |
189 | } |
190 | |
191 | /** |
192 | * find_first_zero_bit - find the first cleared bit in a memory region |
193 | * @addr: The address to start the search at |
194 | * @size: The maximum size to search |
195 | * |
196 | * Returns the bit number of the first cleared bit. |
197 | */ |
198 | static inline unsigned long find_first_zero_bit(const unsigned long *addr, |
199 | unsigned long size) |
200 | { |
201 | return find_next_zero_bit(addr, size, 0); |
202 | } |
203 | |
204 | /** |
205 | * rol8 - rotate an 8-bit value left |
206 | * @word: value to rotate |
207 | * @shift: bits to roll |
208 | */ |
209 | static inline uint8_t rol8(uint8_t word, unsigned int shift) |
210 | { |
211 | return (word << shift) | (word >> ((8 - shift) & 7)); |
212 | } |
213 | |
214 | /** |
215 | * ror8 - rotate an 8-bit value right |
216 | * @word: value to rotate |
217 | * @shift: bits to roll |
218 | */ |
219 | static inline uint8_t ror8(uint8_t word, unsigned int shift) |
220 | { |
221 | return (word >> shift) | (word << ((8 - shift) & 7)); |
222 | } |
223 | |
224 | /** |
225 | * rol16 - rotate a 16-bit value left |
226 | * @word: value to rotate |
227 | * @shift: bits to roll |
228 | */ |
229 | static inline uint16_t rol16(uint16_t word, unsigned int shift) |
230 | { |
231 | return (word << shift) | (word >> ((16 - shift) & 15)); |
232 | } |
233 | |
234 | /** |
235 | * ror16 - rotate a 16-bit value right |
236 | * @word: value to rotate |
237 | * @shift: bits to roll |
238 | */ |
239 | static inline uint16_t ror16(uint16_t word, unsigned int shift) |
240 | { |
241 | return (word >> shift) | (word << ((16 - shift) & 15)); |
242 | } |
243 | |
244 | /** |
245 | * rol32 - rotate a 32-bit value left |
246 | * @word: value to rotate |
247 | * @shift: bits to roll |
248 | */ |
249 | static inline uint32_t rol32(uint32_t word, unsigned int shift) |
250 | { |
251 | return (word << shift) | (word >> ((32 - shift) & 31)); |
252 | } |
253 | |
254 | /** |
255 | * ror32 - rotate a 32-bit value right |
256 | * @word: value to rotate |
257 | * @shift: bits to roll |
258 | */ |
259 | static inline uint32_t ror32(uint32_t word, unsigned int shift) |
260 | { |
261 | return (word >> shift) | (word << ((32 - shift) & 31)); |
262 | } |
263 | |
264 | /** |
265 | * rol64 - rotate a 64-bit value left |
266 | * @word: value to rotate |
267 | * @shift: bits to roll |
268 | */ |
269 | static inline uint64_t rol64(uint64_t word, unsigned int shift) |
270 | { |
271 | return (word << shift) | (word >> ((64 - shift) & 63)); |
272 | } |
273 | |
274 | /** |
275 | * ror64 - rotate a 64-bit value right |
276 | * @word: value to rotate |
277 | * @shift: bits to roll |
278 | */ |
279 | static inline uint64_t ror64(uint64_t word, unsigned int shift) |
280 | { |
281 | return (word >> shift) | (word << ((64 - shift) & 63)); |
282 | } |
283 | |
284 | /** |
285 | * extract32: |
286 | * @value: the value to extract the bit field from |
287 | * @start: the lowest bit in the bit field (numbered from 0) |
288 | * @length: the length of the bit field |
289 | * |
290 | * Extract from the 32 bit input @value the bit field specified by the |
291 | * @start and @length parameters, and return it. The bit field must |
292 | * lie entirely within the 32 bit word. It is valid to request that |
293 | * all 32 bits are returned (ie @length 32 and @start 0). |
294 | * |
295 | * Returns: the value of the bit field extracted from the input value. |
296 | */ |
297 | static inline uint32_t (uint32_t value, int start, int length) |
298 | { |
299 | assert(start >= 0 && length > 0 && length <= 32 - start); |
300 | return (value >> start) & (~0U >> (32 - length)); |
301 | } |
302 | |
303 | /** |
304 | * extract64: |
305 | * @value: the value to extract the bit field from |
306 | * @start: the lowest bit in the bit field (numbered from 0) |
307 | * @length: the length of the bit field |
308 | * |
309 | * Extract from the 64 bit input @value the bit field specified by the |
310 | * @start and @length parameters, and return it. The bit field must |
311 | * lie entirely within the 64 bit word. It is valid to request that |
312 | * all 64 bits are returned (ie @length 64 and @start 0). |
313 | * |
314 | * Returns: the value of the bit field extracted from the input value. |
315 | */ |
316 | static inline uint64_t (uint64_t value, int start, int length) |
317 | { |
318 | assert(start >= 0 && length > 0 && length <= 64 - start); |
319 | return (value >> start) & (~0ULL >> (64 - length)); |
320 | } |
321 | |
322 | /** |
323 | * sextract32: |
324 | * @value: the value to extract the bit field from |
325 | * @start: the lowest bit in the bit field (numbered from 0) |
326 | * @length: the length of the bit field |
327 | * |
328 | * Extract from the 32 bit input @value the bit field specified by the |
329 | * @start and @length parameters, and return it, sign extended to |
330 | * an int32_t (ie with the most significant bit of the field propagated |
331 | * to all the upper bits of the return value). The bit field must lie |
332 | * entirely within the 32 bit word. It is valid to request that |
333 | * all 32 bits are returned (ie @length 32 and @start 0). |
334 | * |
335 | * Returns: the sign extended value of the bit field extracted from the |
336 | * input value. |
337 | */ |
338 | static inline int32_t (uint32_t value, int start, int length) |
339 | { |
340 | assert(start >= 0 && length > 0 && length <= 32 - start); |
341 | /* Note that this implementation relies on right shift of signed |
342 | * integers being an arithmetic shift. |
343 | */ |
344 | return ((int32_t)(value << (32 - length - start))) >> (32 - length); |
345 | } |
346 | |
347 | /** |
348 | * sextract64: |
349 | * @value: the value to extract the bit field from |
350 | * @start: the lowest bit in the bit field (numbered from 0) |
351 | * @length: the length of the bit field |
352 | * |
353 | * Extract from the 64 bit input @value the bit field specified by the |
354 | * @start and @length parameters, and return it, sign extended to |
355 | * an int64_t (ie with the most significant bit of the field propagated |
356 | * to all the upper bits of the return value). The bit field must lie |
357 | * entirely within the 64 bit word. It is valid to request that |
358 | * all 64 bits are returned (ie @length 64 and @start 0). |
359 | * |
360 | * Returns: the sign extended value of the bit field extracted from the |
361 | * input value. |
362 | */ |
363 | static inline int64_t (uint64_t value, int start, int length) |
364 | { |
365 | assert(start >= 0 && length > 0 && length <= 64 - start); |
366 | /* Note that this implementation relies on right shift of signed |
367 | * integers being an arithmetic shift. |
368 | */ |
369 | return ((int64_t)(value << (64 - length - start))) >> (64 - length); |
370 | } |
371 | |
372 | /** |
373 | * deposit32: |
374 | * @value: initial value to insert bit field into |
375 | * @start: the lowest bit in the bit field (numbered from 0) |
376 | * @length: the length of the bit field |
377 | * @fieldval: the value to insert into the bit field |
378 | * |
379 | * Deposit @fieldval into the 32 bit @value at the bit field specified |
380 | * by the @start and @length parameters, and return the modified |
381 | * @value. Bits of @value outside the bit field are not modified. |
382 | * Bits of @fieldval above the least significant @length bits are |
383 | * ignored. The bit field must lie entirely within the 32 bit word. |
384 | * It is valid to request that all 32 bits are modified (ie @length |
385 | * 32 and @start 0). |
386 | * |
387 | * Returns: the modified @value. |
388 | */ |
389 | static inline uint32_t deposit32(uint32_t value, int start, int length, |
390 | uint32_t fieldval) |
391 | { |
392 | uint32_t mask; |
393 | assert(start >= 0 && length > 0 && length <= 32 - start); |
394 | mask = (~0U >> (32 - length)) << start; |
395 | return (value & ~mask) | ((fieldval << start) & mask); |
396 | } |
397 | |
398 | /** |
399 | * deposit64: |
400 | * @value: initial value to insert bit field into |
401 | * @start: the lowest bit in the bit field (numbered from 0) |
402 | * @length: the length of the bit field |
403 | * @fieldval: the value to insert into the bit field |
404 | * |
405 | * Deposit @fieldval into the 64 bit @value at the bit field specified |
406 | * by the @start and @length parameters, and return the modified |
407 | * @value. Bits of @value outside the bit field are not modified. |
408 | * Bits of @fieldval above the least significant @length bits are |
409 | * ignored. The bit field must lie entirely within the 64 bit word. |
410 | * It is valid to request that all 64 bits are modified (ie @length |
411 | * 64 and @start 0). |
412 | * |
413 | * Returns: the modified @value. |
414 | */ |
415 | static inline uint64_t deposit64(uint64_t value, int start, int length, |
416 | uint64_t fieldval) |
417 | { |
418 | uint64_t mask; |
419 | assert(start >= 0 && length > 0 && length <= 64 - start); |
420 | mask = (~0ULL >> (64 - length)) << start; |
421 | return (value & ~mask) | ((fieldval << start) & mask); |
422 | } |
423 | |
424 | /** |
425 | * half_shuffle32: |
426 | * @value: 32-bit value (of which only the bottom 16 bits are of interest) |
427 | * |
428 | * Given an input value: |
429 | * xxxx xxxx xxxx xxxx ABCD EFGH IJKL MNOP |
430 | * return the value where the bottom 16 bits are spread out into |
431 | * the odd bits in the word, and the even bits are zeroed: |
432 | * 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N 0O0P |
433 | * |
434 | * Any bits set in the top half of the input are ignored. |
435 | * |
436 | * Returns: the shuffled bits. |
437 | */ |
438 | static inline uint32_t half_shuffle32(uint32_t x) |
439 | { |
440 | /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". |
441 | * It ignores any bits set in the top half of the input. |
442 | */ |
443 | x = ((x & 0xFF00) << 8) | (x & 0x00FF); |
444 | x = ((x << 4) | x) & 0x0F0F0F0F; |
445 | x = ((x << 2) | x) & 0x33333333; |
446 | x = ((x << 1) | x) & 0x55555555; |
447 | return x; |
448 | } |
449 | |
450 | /** |
451 | * half_shuffle64: |
452 | * @value: 64-bit value (of which only the bottom 32 bits are of interest) |
453 | * |
454 | * Given an input value: |
455 | * xxxx xxxx xxxx .... xxxx xxxx ABCD EFGH IJKL MNOP QRST UVWX YZab cdef |
456 | * return the value where the bottom 32 bits are spread out into |
457 | * the odd bits in the word, and the even bits are zeroed: |
458 | * 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N .... 0U0V 0W0X 0Y0Z 0a0b 0c0d 0e0f |
459 | * |
460 | * Any bits set in the top half of the input are ignored. |
461 | * |
462 | * Returns: the shuffled bits. |
463 | */ |
464 | static inline uint64_t half_shuffle64(uint64_t x) |
465 | { |
466 | /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". |
467 | * It ignores any bits set in the top half of the input. |
468 | */ |
469 | x = ((x & 0xFFFF0000ULL) << 16) | (x & 0xFFFF); |
470 | x = ((x << 8) | x) & 0x00FF00FF00FF00FFULL; |
471 | x = ((x << 4) | x) & 0x0F0F0F0F0F0F0F0FULL; |
472 | x = ((x << 2) | x) & 0x3333333333333333ULL; |
473 | x = ((x << 1) | x) & 0x5555555555555555ULL; |
474 | return x; |
475 | } |
476 | |
477 | /** |
478 | * half_unshuffle32: |
479 | * @value: 32-bit value (of which only the odd bits are of interest) |
480 | * |
481 | * Given an input value: |
482 | * xAxB xCxD xExF xGxH xIxJ xKxL xMxN xOxP |
483 | * return the value where all the odd bits are compressed down |
484 | * into the low half of the word, and the high half is zeroed: |
485 | * 0000 0000 0000 0000 ABCD EFGH IJKL MNOP |
486 | * |
487 | * Any even bits set in the input are ignored. |
488 | * |
489 | * Returns: the unshuffled bits. |
490 | */ |
491 | static inline uint32_t half_unshuffle32(uint32_t x) |
492 | { |
493 | /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". |
494 | * where it is called an inverse half shuffle. |
495 | */ |
496 | x &= 0x55555555; |
497 | x = ((x >> 1) | x) & 0x33333333; |
498 | x = ((x >> 2) | x) & 0x0F0F0F0F; |
499 | x = ((x >> 4) | x) & 0x00FF00FF; |
500 | x = ((x >> 8) | x) & 0x0000FFFF; |
501 | return x; |
502 | } |
503 | |
504 | /** |
505 | * half_unshuffle64: |
506 | * @value: 64-bit value (of which only the odd bits are of interest) |
507 | * |
508 | * Given an input value: |
509 | * xAxB xCxD xExF xGxH xIxJ xKxL xMxN .... xUxV xWxX xYxZ xaxb xcxd xexf |
510 | * return the value where all the odd bits are compressed down |
511 | * into the low half of the word, and the high half is zeroed: |
512 | * 0000 0000 0000 .... 0000 0000 ABCD EFGH IJKL MNOP QRST UVWX YZab cdef |
513 | * |
514 | * Any even bits set in the input are ignored. |
515 | * |
516 | * Returns: the unshuffled bits. |
517 | */ |
518 | static inline uint64_t half_unshuffle64(uint64_t x) |
519 | { |
520 | /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". |
521 | * where it is called an inverse half shuffle. |
522 | */ |
523 | x &= 0x5555555555555555ULL; |
524 | x = ((x >> 1) | x) & 0x3333333333333333ULL; |
525 | x = ((x >> 2) | x) & 0x0F0F0F0F0F0F0F0FULL; |
526 | x = ((x >> 4) | x) & 0x00FF00FF00FF00FFULL; |
527 | x = ((x >> 8) | x) & 0x0000FFFF0000FFFFULL; |
528 | x = ((x >> 16) | x) & 0x00000000FFFFFFFFULL; |
529 | return x; |
530 | } |
531 | |
532 | #endif |
533 | |