1 /*- 2 * Copyright (c) 2011 Ed Schouten <ed (at) FreeBSD.org> 3 * David Chisnall <theraven (at) FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 #ifndef _STDATOMIC_H_ 31 #define _STDATOMIC_H_ 32 33 #include <sys/cdefs.h> 34 35 36 #if defined(__cplusplus) && defined(_USING_LIBCXX) 37 # ifdef __clang__ 38 # if __has_feature(cxx_atomic) 39 # define _STDATOMIC_HAVE_ATOMIC 40 # endif 41 # else /* gcc */ 42 # if __GNUC_PREREQ(4, 7) 43 # define _STDATOMIC_HAVE_ATOMIC 44 # endif 45 # endif 46 #endif 47 48 #ifdef _STDATOMIC_HAVE_ATOMIC 49 50 /* We have a usable C++ <atomic>; use it instead. */ 51 52 #include <atomic> 53 54 #undef _Atomic 55 /* Also defined by <atomic> for gcc. But not used in macros. */ 56 /* Also a clang intrinsic. */ 57 /* Should not be used by client code before this file is */ 58 /* included. The definitions in <atomic> themselves see */ 59 /* the old definition, as they should. */ 60 /* Client code sees the following definition. */ 61 62 #define _Atomic(t) std::atomic<t> 63 64 using std::atomic_is_lock_free; 65 using std::atomic_init; 66 using std::atomic_store; 67 using std::atomic_store_explicit; 68 using std::atomic_load; 69 using std::atomic_load_explicit; 70 using std::atomic_exchange; 71 using std::atomic_exchange_explicit; 72 using std::atomic_compare_exchange_strong; 73 using std::atomic_compare_exchange_strong_explicit; 74 using std::atomic_compare_exchange_weak; 75 using std::atomic_compare_exchange_weak_explicit; 76 using std::atomic_fetch_add; 77 using std::atomic_fetch_add_explicit; 78 using std::atomic_fetch_sub; 79 using std::atomic_fetch_sub_explicit; 80 using std::atomic_fetch_or; 81 using std::atomic_fetch_or_explicit; 82 using std::atomic_fetch_xor; 83 using std::atomic_fetch_xor_explicit; 84 using std::atomic_fetch_and; 85 using std::atomic_fetch_and_explicit; 86 using std::atomic_thread_fence; 87 using std::atomic_signal_fence; 88 89 using std::memory_order; 90 using std::memory_order_relaxed; 91 using std::memory_order_consume; 92 using std::memory_order_release; 93 using std::memory_order_acq_rel; 94 using std::memory_order_seq_cst; 95 96 using std::atomic_bool; 97 using std::atomic_char; 98 using std::atomic_schar; 99 using std::atomic_uchar; 100 using std::atomic_short; 101 using std::atomic_ushort; 102 using std::atomic_int; 103 using std::atomic_uint; 104 using std::atomic_long; 105 using std::atomic_ulong; 106 using std::atomic_llong; 107 using std::atomic_ullong; 108 using std::atomic_char16_t; 109 using std::atomic_char32_t; 110 using std::atomic_wchar_t; 111 using std::atomic_int_least8_t; 112 using std::atomic_uint_least8_t; 113 using std::atomic_int_least16_t; 114 using std::atomic_uint_least16_t; 115 using std::atomic_int_least32_t; 116 using std::atomic_uint_least32_t; 117 using std::atomic_int_least64_t; 118 using std::atomic_uint_least64_t; 119 using std::atomic_int_fast8_t; 120 using std::atomic_uint_fast8_t; 121 using std::atomic_int_fast16_t; 122 using std::atomic_uint_fast16_t; 123 using std::atomic_int_fast32_t; 124 using std::atomic_uint_fast32_t; 125 using std::atomic_int_fast64_t; 126 using std::atomic_uint_fast64_t; 127 using std::atomic_intptr_t; 128 using std::atomic_uintptr_t; 129 using std::atomic_size_t; 130 using std::atomic_ptrdiff_t; 131 using std::atomic_intmax_t; 132 using std::atomic_uintmax_t; 133 134 #else /* <atomic> unavailable, possibly because this is C, not C++ */ 135 136 #include <sys/types.h> 137 #include <stdbool.h> 138 139 /* 140 * C: Do it ourselves. 141 * Note that the runtime representation defined here should be compatible 142 * with the C++ one, i.e. an _Atomic(T) needs to contain the same 143 * bits as a T. 144 */ 145 146 #include <stddef.h> /* For ptrdiff_t. */ 147 #include <stdint.h> /* TODO: Should pollute namespace less. */ 148 #if __STDC_VERSION__ >= 201112L 149 # include <uchar.h> /* For char16_t and char32_t. */ 150 #endif 151 152 #ifdef __clang__ 153 # if __has_extension(c_atomic) || __has_extension(cxx_atomic) 154 # define __CLANG_ATOMICS 155 # else 156 # error "stdatomic.h does not support your compiler" 157 # endif 158 # if __has_builtin(__sync_swap) 159 # define __HAS_BUILTIN_SYNC_SWAP 160 # endif 161 #else 162 # if __GNUC_PREREQ(4, 7) 163 # define __GNUC_ATOMICS 164 # else 165 # define __SYNC_ATOMICS 166 # ifdef __cplusplus 167 # define __ATOMICS_AVOID_DOT_INIT 168 # endif 169 # endif 170 #endif 171 172 /* 173 * 7.17.1 Atomic lock-free macros. 174 */ 175 176 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE 177 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE 178 #elif defined(__SYNC_ATOMICS) 179 #define ATOMIC_BOOL_LOCK_FREE 2 /* For all modern platforms */ 180 #endif 181 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE 182 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE 183 #elif defined(__SYNC_ATOMICS) 184 #define ATOMIC_CHAR_LOCK_FREE 2 185 #endif 186 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE 187 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE 188 #elif defined(__SYNC_ATOMICS) 189 #define ATOMIC_CHAR16_T_LOCK_FREE 2 190 #endif 191 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE 192 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE 193 #elif defined(__SYNC_ATOMICS) 194 #define ATOMIC_CHAR32_T_LOCK_FREE 2 195 #endif 196 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE 197 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE 198 #elif defined(__SYNC_ATOMICS) 199 #define ATOMIC_WCHAR_T_LOCK_FREE 2 200 #endif 201 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE 202 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE 203 #elif defined(__SYNC_ATOMICS) 204 #define ATOMIC_SHORT_LOCK_FREE 2 205 #endif 206 #ifdef __GCC_ATOMIC_INT_LOCK_FREE 207 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE 208 #elif defined(__SYNC_ATOMICS) 209 #define ATOMIC_INT_LOCK_FREE 2 210 #endif 211 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE 212 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE 213 #elif defined(__SYNC_ATOMICS) 214 #define ATOMIC_LONG_LOCK_FREE 2 215 #endif 216 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE 217 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE 218 #elif defined(__SYNC_ATOMICS) 219 #define ATOMIC_LLONG_LOCK_FREE 1 /* maybe */ 220 #endif 221 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE 222 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE 223 #elif defined(__SYNC_ATOMICS) 224 #define ATOMIC_POINTER_LOCK_FREE 2 225 #endif 226 227 /* 228 * 7.17.2 Initialization. 229 */ 230 231 #if defined(__CLANG_ATOMICS) 232 #define ATOMIC_VAR_INIT(value) (value) 233 #define atomic_init(obj, value) __c11_atomic_init(obj, value) 234 #else 235 #ifdef __ATOMICS_AVOID_DOT_INIT 236 #define ATOMIC_VAR_INIT(value) { value } 237 #else 238 #define ATOMIC_VAR_INIT(value) { .__val = (value) } 239 #endif 240 #define atomic_init(obj, value) ((void)((obj)->__val = (value))) 241 #endif 242 243 /* 244 * Clang and recent GCC both provide predefined macros for the memory 245 * orderings. If we are using a compiler that doesn't define them, use the 246 * clang values - these will be ignored in the fallback path. 247 */ 248 249 #ifndef __ATOMIC_RELAXED 250 #define __ATOMIC_RELAXED 0 251 #endif 252 #ifndef __ATOMIC_CONSUME 253 #define __ATOMIC_CONSUME 1 254 #endif 255 #ifndef __ATOMIC_ACQUIRE 256 #define __ATOMIC_ACQUIRE 2 257 #endif 258 #ifndef __ATOMIC_RELEASE 259 #define __ATOMIC_RELEASE 3 260 #endif 261 #ifndef __ATOMIC_ACQ_REL 262 #define __ATOMIC_ACQ_REL 4 263 #endif 264 #ifndef __ATOMIC_SEQ_CST 265 #define __ATOMIC_SEQ_CST 5 266 #endif 267 268 /* 269 * 7.17.3 Order and consistency. 270 * 271 * The memory_order_* constants that denote the barrier behaviour of the 272 * atomic operations. 273 * The enum values must be identical to those used by the 274 * C++ <atomic> header. 275 */ 276 277 typedef enum { 278 memory_order_relaxed = __ATOMIC_RELAXED, 279 memory_order_consume = __ATOMIC_CONSUME, 280 memory_order_acquire = __ATOMIC_ACQUIRE, 281 memory_order_release = __ATOMIC_RELEASE, 282 memory_order_acq_rel = __ATOMIC_ACQ_REL, 283 memory_order_seq_cst = __ATOMIC_SEQ_CST 284 } memory_order; 285 286 /* 287 * 7.17.4 Fences. 288 */ 289 290 static __inline void 291 atomic_thread_fence(memory_order __order __attribute__((unused))) 292 { 293 294 #ifdef __CLANG_ATOMICS 295 __c11_atomic_thread_fence(__order); 296 #elif defined(__GNUC_ATOMICS) 297 __atomic_thread_fence(__order); 298 #else 299 __sync_synchronize(); 300 #endif 301 } 302 303 static __inline void 304 atomic_signal_fence(memory_order __order __attribute__((unused))) 305 { 306 307 #ifdef __CLANG_ATOMICS 308 __c11_atomic_signal_fence(__order); 309 #elif defined(__GNUC_ATOMICS) 310 __atomic_signal_fence(__order); 311 #else 312 __asm volatile ("" ::: "memory"); 313 #endif 314 } 315 316 /* 317 * 7.17.5 Lock-free property. 318 */ 319 320 #if defined(_KERNEL) 321 /* Atomics in kernelspace are always lock-free. */ 322 #define atomic_is_lock_free(obj) \ 323 ((void)(obj), (_Bool)1) 324 #elif defined(__CLANG_ATOMICS) 325 #define atomic_is_lock_free(obj) \ 326 __c11_atomic_is_lock_free(sizeof(*(obj))) 327 #elif defined(__GNUC_ATOMICS) 328 #define atomic_is_lock_free(obj) \ 329 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) 330 #else 331 #define atomic_is_lock_free(obj) \ 332 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) 333 #endif 334 335 /* 336 * 7.17.6 Atomic integer types. 337 */ 338 339 #ifndef __CLANG_ATOMICS 340 /* 341 * No native support for _Atomic(). Place object in structure to prevent 342 * most forms of direct non-atomic access. 343 */ 344 #define _Atomic(T) struct { T volatile __val; } 345 #endif 346 347 typedef _Atomic(bool) atomic_bool; 348 typedef _Atomic(char) atomic_char; 349 typedef _Atomic(signed char) atomic_schar; 350 typedef _Atomic(unsigned char) atomic_uchar; 351 typedef _Atomic(short) atomic_short; 352 typedef _Atomic(unsigned short) atomic_ushort; 353 typedef _Atomic(int) atomic_int; 354 typedef _Atomic(unsigned int) atomic_uint; 355 typedef _Atomic(long) atomic_long; 356 typedef _Atomic(unsigned long) atomic_ulong; 357 typedef _Atomic(long long) atomic_llong; 358 typedef _Atomic(unsigned long long) atomic_ullong; 359 #if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L 360 typedef _Atomic(char16_t) atomic_char16_t; 361 typedef _Atomic(char32_t) atomic_char32_t; 362 #endif 363 typedef _Atomic(wchar_t) atomic_wchar_t; 364 typedef _Atomic(int_least8_t) atomic_int_least8_t; 365 typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 366 typedef _Atomic(int_least16_t) atomic_int_least16_t; 367 typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 368 typedef _Atomic(int_least32_t) atomic_int_least32_t; 369 typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 370 typedef _Atomic(int_least64_t) atomic_int_least64_t; 371 typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 372 typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 373 typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 374 typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 375 typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 376 typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 377 typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 378 typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 379 typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 380 typedef _Atomic(intptr_t) atomic_intptr_t; 381 typedef _Atomic(uintptr_t) atomic_uintptr_t; 382 typedef _Atomic(size_t) atomic_size_t; 383 typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 384 typedef _Atomic(intmax_t) atomic_intmax_t; 385 typedef _Atomic(uintmax_t) atomic_uintmax_t; 386 387 /* 388 * 7.17.7 Operations on atomic types. 389 */ 390 391 /* 392 * Compiler-specific operations. 393 */ 394 395 #if defined(__CLANG_ATOMICS) 396 #define atomic_compare_exchange_strong_explicit(object, expected, \ 397 desired, success, failure) \ 398 __c11_atomic_compare_exchange_strong(object, expected, desired, \ 399 success, failure) 400 #define atomic_compare_exchange_weak_explicit(object, expected, \ 401 desired, success, failure) \ 402 __c11_atomic_compare_exchange_weak(object, expected, desired, \ 403 success, failure) 404 #define atomic_exchange_explicit(object, desired, order) \ 405 __c11_atomic_exchange(object, desired, order) 406 #define atomic_fetch_add_explicit(object, operand, order) \ 407 __c11_atomic_fetch_add(object, operand, order) 408 #define atomic_fetch_and_explicit(object, operand, order) \ 409 __c11_atomic_fetch_and(object, operand, order) 410 #define atomic_fetch_or_explicit(object, operand, order) \ 411 __c11_atomic_fetch_or(object, operand, order) 412 #define atomic_fetch_sub_explicit(object, operand, order) \ 413 __c11_atomic_fetch_sub(object, operand, order) 414 #define atomic_fetch_xor_explicit(object, operand, order) \ 415 __c11_atomic_fetch_xor(object, operand, order) 416 #define atomic_load_explicit(object, order) \ 417 __c11_atomic_load(object, order) 418 #define atomic_store_explicit(object, desired, order) \ 419 __c11_atomic_store(object, desired, order) 420 #elif defined(__GNUC_ATOMICS) 421 #define atomic_compare_exchange_strong_explicit(object, expected, \ 422 desired, success, failure) \ 423 __atomic_compare_exchange_n(&(object)->__val, expected, \ 424 desired, 0, success, failure) 425 #define atomic_compare_exchange_weak_explicit(object, expected, \ 426 desired, success, failure) \ 427 __atomic_compare_exchange_n(&(object)->__val, expected, \ 428 desired, 1, success, failure) 429 #define atomic_exchange_explicit(object, desired, order) \ 430 __atomic_exchange_n(&(object)->__val, desired, order) 431 #define atomic_fetch_add_explicit(object, operand, order) \ 432 __atomic_fetch_add(&(object)->__val, operand, order) 433 #define atomic_fetch_and_explicit(object, operand, order) \ 434 __atomic_fetch_and(&(object)->__val, operand, order) 435 #define atomic_fetch_or_explicit(object, operand, order) \ 436 __atomic_fetch_or(&(object)->__val, operand, order) 437 #define atomic_fetch_sub_explicit(object, operand, order) \ 438 __atomic_fetch_sub(&(object)->__val, operand, order) 439 #define atomic_fetch_xor_explicit(object, operand, order) \ 440 __atomic_fetch_xor(&(object)->__val, operand, order) 441 #define atomic_load_explicit(object, order) \ 442 __atomic_load_n(&(object)->__val, order) 443 #define atomic_store_explicit(object, desired, order) \ 444 __atomic_store_n(&(object)->__val, desired, order) 445 #else 446 #define __atomic_apply_stride(object, operand) \ 447 (((__typeof__((object)->__val))0) + (operand)) 448 #define atomic_compare_exchange_strong_explicit(object, expected, \ 449 desired, success, failure) __extension__ ({ \ 450 __typeof__(expected) __ep = (expected); \ 451 __typeof__(*__ep) __e = *__ep; \ 452 (void)(success); (void)(failure); \ 453 (bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \ 454 __e, desired)) == __e); \ 455 }) 456 #define atomic_compare_exchange_weak_explicit(object, expected, \ 457 desired, success, failure) \ 458 atomic_compare_exchange_strong_explicit(object, expected, \ 459 desired, success, failure) 460 #ifdef __HAS_BUILTIN_SYNC_SWAP 461 /* Clang provides a full-barrier atomic exchange - use it if available. */ 462 #define atomic_exchange_explicit(object, desired, order) \ 463 ((void)(order), __sync_swap(&(object)->__val, desired)) 464 #else 465 /* 466 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in 467 * practice it is usually a full barrier) so we need an explicit barrier before 468 * it. 469 */ 470 #define atomic_exchange_explicit(object, desired, order) \ 471 __extension__ ({ \ 472 __typeof__(object) __o = (object); \ 473 __typeof__(desired) __d = (desired); \ 474 (void)(order); \ 475 __sync_synchronize(); \ 476 __sync_lock_test_and_set(&(__o)->__val, __d); \ 477 }) 478 #endif 479 #define atomic_fetch_add_explicit(object, operand, order) \ 480 ((void)(order), __sync_fetch_and_add(&(object)->__val, \ 481 __atomic_apply_stride(object, operand))) 482 #define atomic_fetch_and_explicit(object, operand, order) \ 483 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand)) 484 #define atomic_fetch_or_explicit(object, operand, order) \ 485 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand)) 486 #define atomic_fetch_sub_explicit(object, operand, order) \ 487 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \ 488 __atomic_apply_stride(object, operand))) 489 #define atomic_fetch_xor_explicit(object, operand, order) \ 490 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand)) 491 #define atomic_load_explicit(object, order) \ 492 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0)) 493 #define atomic_store_explicit(object, desired, order) \ 494 ((void)atomic_exchange_explicit(object, desired, order)) 495 #endif 496 497 /* 498 * Convenience functions. 499 * 500 * Don't provide these in kernel space. In kernel space, we should be 501 * disciplined enough to always provide explicit barriers. 502 */ 503 504 #ifndef _KERNEL 505 #define atomic_compare_exchange_strong(object, expected, desired) \ 506 atomic_compare_exchange_strong_explicit(object, expected, \ 507 desired, memory_order_seq_cst, memory_order_seq_cst) 508 #define atomic_compare_exchange_weak(object, expected, desired) \ 509 atomic_compare_exchange_weak_explicit(object, expected, \ 510 desired, memory_order_seq_cst, memory_order_seq_cst) 511 #define atomic_exchange(object, desired) \ 512 atomic_exchange_explicit(object, desired, memory_order_seq_cst) 513 #define atomic_fetch_add(object, operand) \ 514 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst) 515 #define atomic_fetch_and(object, operand) \ 516 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst) 517 #define atomic_fetch_or(object, operand) \ 518 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst) 519 #define atomic_fetch_sub(object, operand) \ 520 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst) 521 #define atomic_fetch_xor(object, operand) \ 522 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst) 523 #define atomic_load(object) \ 524 atomic_load_explicit(object, memory_order_seq_cst) 525 #define atomic_store(object, desired) \ 526 atomic_store_explicit(object, desired, memory_order_seq_cst) 527 #endif /* !_KERNEL */ 528 529 /* 530 * 7.17.8 Atomic flag type and operations. 531 * 532 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some 533 * kind of compiler built-in type we could use? 534 */ 535 536 typedef struct { 537 atomic_bool __flag; 538 } atomic_flag; 539 540 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(false) } 541 542 static __inline bool 543 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 544 memory_order __order) 545 { 546 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 547 } 548 549 static __inline void 550 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 551 { 552 553 atomic_store_explicit(&__object->__flag, 0, __order); 554 } 555 556 #ifndef _KERNEL 557 static __inline bool 558 atomic_flag_test_and_set(volatile atomic_flag *__object) 559 { 560 561 return (atomic_flag_test_and_set_explicit(__object, 562 memory_order_seq_cst)); 563 } 564 565 static __inline void 566 atomic_flag_clear(volatile atomic_flag *__object) 567 { 568 569 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 570 } 571 #endif /* !_KERNEL */ 572 573 #endif /* <atomic> unavailable */ 574 575 #endif /* !_STDATOMIC_H_ */ 576
