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) && __cplusplus >= 201103L && 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_acquire; 93 using std::memory_order_release; 94 using std::memory_order_acq_rel; 95 using std::memory_order_seq_cst; 96 97 using std::atomic_bool; 98 using std::atomic_char; 99 using std::atomic_schar; 100 using std::atomic_uchar; 101 using std::atomic_short; 102 using std::atomic_ushort; 103 using std::atomic_int; 104 using std::atomic_uint; 105 using std::atomic_long; 106 using std::atomic_ulong; 107 using std::atomic_llong; 108 using std::atomic_ullong; 109 using std::atomic_char16_t; 110 using std::atomic_char32_t; 111 using std::atomic_wchar_t; 112 using std::atomic_int_least8_t; 113 using std::atomic_uint_least8_t; 114 using std::atomic_int_least16_t; 115 using std::atomic_uint_least16_t; 116 using std::atomic_int_least32_t; 117 using std::atomic_uint_least32_t; 118 using std::atomic_int_least64_t; 119 using std::atomic_uint_least64_t; 120 using std::atomic_int_fast8_t; 121 using std::atomic_uint_fast8_t; 122 using std::atomic_int_fast16_t; 123 using std::atomic_uint_fast16_t; 124 using std::atomic_int_fast32_t; 125 using std::atomic_uint_fast32_t; 126 using std::atomic_int_fast64_t; 127 using std::atomic_uint_fast64_t; 128 using std::atomic_intptr_t; 129 using std::atomic_uintptr_t; 130 using std::atomic_size_t; 131 using std::atomic_ptrdiff_t; 132 using std::atomic_intmax_t; 133 using std::atomic_uintmax_t; 134 135 #else /* <atomic> unavailable, possibly because this is C, not C++ */ 136 137 #include <sys/types.h> 138 #include <stdbool.h> 139 140 /* 141 * C: Do it ourselves. 142 * Note that the runtime representation defined here should be compatible 143 * with the C++ one, i.e. an _Atomic(T) needs to contain the same 144 * bits as a T. 145 */ 146 147 #include <stddef.h> /* For ptrdiff_t. */ 148 #include <stdint.h> /* TODO: Should pollute namespace less. */ 149 #if __STDC_VERSION__ >= 201112L 150 # include <uchar.h> /* For char16_t and char32_t. */ 151 #endif 152 153 #ifdef __clang__ 154 # if __has_extension(c_atomic) || __has_extension(cxx_atomic) 155 # define __CLANG_ATOMICS 156 # else 157 # error "stdatomic.h does not support your compiler" 158 # endif 159 # if __has_builtin(__sync_swap) 160 # define __HAS_BUILTIN_SYNC_SWAP 161 # endif 162 #else 163 # if __GNUC_PREREQ(4, 7) 164 # define __GNUC_ATOMICS 165 # else 166 # define __SYNC_ATOMICS 167 # ifdef __cplusplus 168 # define __ATOMICS_AVOID_DOT_INIT 169 # endif 170 # endif 171 #endif 172 173 /* 174 * 7.17.1 Atomic lock-free macros. 175 */ 176 177 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE 178 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE 179 #elif defined(__SYNC_ATOMICS) 180 #define ATOMIC_BOOL_LOCK_FREE 2 /* For all modern platforms */ 181 #endif 182 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE 183 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE 184 #elif defined(__SYNC_ATOMICS) 185 #define ATOMIC_CHAR_LOCK_FREE 2 186 #endif 187 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE 188 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE 189 #elif defined(__SYNC_ATOMICS) 190 #define ATOMIC_CHAR16_T_LOCK_FREE 2 191 #endif 192 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE 193 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE 194 #elif defined(__SYNC_ATOMICS) 195 #define ATOMIC_CHAR32_T_LOCK_FREE 2 196 #endif 197 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE 198 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE 199 #elif defined(__SYNC_ATOMICS) 200 #define ATOMIC_WCHAR_T_LOCK_FREE 2 201 #endif 202 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE 203 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE 204 #elif defined(__SYNC_ATOMICS) 205 #define ATOMIC_SHORT_LOCK_FREE 2 206 #endif 207 #ifdef __GCC_ATOMIC_INT_LOCK_FREE 208 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE 209 #elif defined(__SYNC_ATOMICS) 210 #define ATOMIC_INT_LOCK_FREE 2 211 #endif 212 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE 213 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE 214 #elif defined(__SYNC_ATOMICS) 215 #define ATOMIC_LONG_LOCK_FREE 2 216 #endif 217 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE 218 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE 219 #elif defined(__SYNC_ATOMICS) 220 #define ATOMIC_LLONG_LOCK_FREE 1 /* maybe */ 221 #endif 222 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE 223 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE 224 #elif defined(__SYNC_ATOMICS) 225 #define ATOMIC_POINTER_LOCK_FREE 2 226 #endif 227 228 /* 229 * 7.17.2 Initialization. 230 */ 231 232 #if defined(__CLANG_ATOMICS) 233 #define ATOMIC_VAR_INIT(value) (value) 234 #define atomic_init(obj, value) __c11_atomic_init(obj, value) 235 #else 236 #ifdef __ATOMICS_AVOID_DOT_INIT 237 #define ATOMIC_VAR_INIT(value) { value } 238 #else 239 #define ATOMIC_VAR_INIT(value) { .__val = (value) } 240 #endif 241 #define atomic_init(obj, value) ((void)((obj)->__val = (value))) 242 #endif 243 244 /* 245 * Clang and recent GCC both provide predefined macros for the memory 246 * orderings. If we are using a compiler that doesn't define them, use the 247 * clang values - these will be ignored in the fallback path. 248 */ 249 250 #ifndef __ATOMIC_RELAXED 251 #define __ATOMIC_RELAXED 0 252 #endif 253 #ifndef __ATOMIC_CONSUME 254 #define __ATOMIC_CONSUME 1 255 #endif 256 #ifndef __ATOMIC_ACQUIRE 257 #define __ATOMIC_ACQUIRE 2 258 #endif 259 #ifndef __ATOMIC_RELEASE 260 #define __ATOMIC_RELEASE 3 261 #endif 262 #ifndef __ATOMIC_ACQ_REL 263 #define __ATOMIC_ACQ_REL 4 264 #endif 265 #ifndef __ATOMIC_SEQ_CST 266 #define __ATOMIC_SEQ_CST 5 267 #endif 268 269 /* 270 * 7.17.3 Order and consistency. 271 * 272 * The memory_order_* constants that denote the barrier behaviour of the 273 * atomic operations. 274 * The enum values must be identical to those used by the 275 * C++ <atomic> header. 276 */ 277 278 typedef enum { 279 memory_order_relaxed = __ATOMIC_RELAXED, 280 memory_order_consume = __ATOMIC_CONSUME, 281 memory_order_acquire = __ATOMIC_ACQUIRE, 282 memory_order_release = __ATOMIC_RELEASE, 283 memory_order_acq_rel = __ATOMIC_ACQ_REL, 284 memory_order_seq_cst = __ATOMIC_SEQ_CST 285 } memory_order; 286 287 /* 288 * 7.17.4 Fences. 289 */ 290 291 static __inline void 292 atomic_thread_fence(memory_order __order __attribute__((unused))) 293 { 294 295 #ifdef __CLANG_ATOMICS 296 __c11_atomic_thread_fence(__order); 297 #elif defined(__GNUC_ATOMICS) 298 __atomic_thread_fence(__order); 299 #else 300 __sync_synchronize(); 301 #endif 302 } 303 304 static __inline void 305 atomic_signal_fence(memory_order __order __attribute__((unused))) 306 { 307 308 #ifdef __CLANG_ATOMICS 309 __c11_atomic_signal_fence(__order); 310 #elif defined(__GNUC_ATOMICS) 311 __atomic_signal_fence(__order); 312 #else 313 __asm volatile ("" ::: "memory"); 314 #endif 315 } 316 317 /* 318 * 7.17.5 Lock-free property. 319 */ 320 321 #if defined(_KERNEL) 322 /* Atomics in kernelspace are always lock-free. */ 323 #define atomic_is_lock_free(obj) \ 324 ((void)(obj), (_Bool)1) 325 #elif defined(__CLANG_ATOMICS) 326 #define atomic_is_lock_free(obj) \ 327 __c11_atomic_is_lock_free(sizeof(*(obj))) 328 #elif defined(__GNUC_ATOMICS) 329 #define atomic_is_lock_free(obj) \ 330 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) 331 #else 332 #define atomic_is_lock_free(obj) \ 333 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) 334 #endif 335 336 /* 337 * 7.17.6 Atomic integer types. 338 */ 339 340 #ifndef __CLANG_ATOMICS 341 /* 342 * No native support for _Atomic(). Place object in structure to prevent 343 * most forms of direct non-atomic access. 344 */ 345 #define _Atomic(T) struct { T volatile __val; } 346 #endif 347 348 typedef _Atomic(bool) atomic_bool; 349 typedef _Atomic(char) atomic_char; 350 typedef _Atomic(signed char) atomic_schar; 351 typedef _Atomic(unsigned char) atomic_uchar; 352 typedef _Atomic(short) atomic_short; 353 typedef _Atomic(unsigned short) atomic_ushort; 354 typedef _Atomic(int) atomic_int; 355 typedef _Atomic(unsigned int) atomic_uint; 356 typedef _Atomic(long) atomic_long; 357 typedef _Atomic(unsigned long) atomic_ulong; 358 typedef _Atomic(long long) atomic_llong; 359 typedef _Atomic(unsigned long long) atomic_ullong; 360 #if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L 361 typedef _Atomic(char16_t) atomic_char16_t; 362 typedef _Atomic(char32_t) atomic_char32_t; 363 #endif 364 typedef _Atomic(wchar_t) atomic_wchar_t; 365 typedef _Atomic(int_least8_t) atomic_int_least8_t; 366 typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 367 typedef _Atomic(int_least16_t) atomic_int_least16_t; 368 typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 369 typedef _Atomic(int_least32_t) atomic_int_least32_t; 370 typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 371 typedef _Atomic(int_least64_t) atomic_int_least64_t; 372 typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 373 typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 374 typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 375 typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 376 typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 377 typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 378 typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 379 typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 380 typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 381 typedef _Atomic(intptr_t) atomic_intptr_t; 382 typedef _Atomic(uintptr_t) atomic_uintptr_t; 383 typedef _Atomic(size_t) atomic_size_t; 384 typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 385 typedef _Atomic(intmax_t) atomic_intmax_t; 386 typedef _Atomic(uintmax_t) atomic_uintmax_t; 387 388 /* 389 * 7.17.7 Operations on atomic types. 390 */ 391 392 /* 393 * Compiler-specific operations. 394 */ 395 396 #if defined(__CLANG_ATOMICS) 397 #define atomic_compare_exchange_strong_explicit(object, expected, \ 398 desired, success, failure) \ 399 __c11_atomic_compare_exchange_strong(object, expected, desired, \ 400 success, failure) 401 #define atomic_compare_exchange_weak_explicit(object, expected, \ 402 desired, success, failure) \ 403 __c11_atomic_compare_exchange_weak(object, expected, desired, \ 404 success, failure) 405 #define atomic_exchange_explicit(object, desired, order) \ 406 __c11_atomic_exchange(object, desired, order) 407 #define atomic_fetch_add_explicit(object, operand, order) \ 408 __c11_atomic_fetch_add(object, operand, order) 409 #define atomic_fetch_and_explicit(object, operand, order) \ 410 __c11_atomic_fetch_and(object, operand, order) 411 #define atomic_fetch_or_explicit(object, operand, order) \ 412 __c11_atomic_fetch_or(object, operand, order) 413 #define atomic_fetch_sub_explicit(object, operand, order) \ 414 __c11_atomic_fetch_sub(object, operand, order) 415 #define atomic_fetch_xor_explicit(object, operand, order) \ 416 __c11_atomic_fetch_xor(object, operand, order) 417 #define atomic_load_explicit(object, order) \ 418 __c11_atomic_load(object, order) 419 #define atomic_store_explicit(object, desired, order) \ 420 __c11_atomic_store(object, desired, order) 421 #elif defined(__GNUC_ATOMICS) 422 #define atomic_compare_exchange_strong_explicit(object, expected, \ 423 desired, success, failure) \ 424 __atomic_compare_exchange_n(&(object)->__val, expected, \ 425 desired, 0, success, failure) 426 #define atomic_compare_exchange_weak_explicit(object, expected, \ 427 desired, success, failure) \ 428 __atomic_compare_exchange_n(&(object)->__val, expected, \ 429 desired, 1, success, failure) 430 #define atomic_exchange_explicit(object, desired, order) \ 431 __atomic_exchange_n(&(object)->__val, desired, order) 432 #define atomic_fetch_add_explicit(object, operand, order) \ 433 __atomic_fetch_add(&(object)->__val, operand, order) 434 #define atomic_fetch_and_explicit(object, operand, order) \ 435 __atomic_fetch_and(&(object)->__val, operand, order) 436 #define atomic_fetch_or_explicit(object, operand, order) \ 437 __atomic_fetch_or(&(object)->__val, operand, order) 438 #define atomic_fetch_sub_explicit(object, operand, order) \ 439 __atomic_fetch_sub(&(object)->__val, operand, order) 440 #define atomic_fetch_xor_explicit(object, operand, order) \ 441 __atomic_fetch_xor(&(object)->__val, operand, order) 442 #define atomic_load_explicit(object, order) \ 443 __atomic_load_n(&(object)->__val, order) 444 #define atomic_store_explicit(object, desired, order) \ 445 __atomic_store_n(&(object)->__val, desired, order) 446 #else 447 #define __atomic_apply_stride(object, operand) \ 448 (((__typeof__((object)->__val))0) + (operand)) 449 #define atomic_compare_exchange_strong_explicit(object, expected, \ 450 desired, success, failure) __extension__ ({ \ 451 __typeof__(expected) __ep = (expected); \ 452 __typeof__(*__ep) __e = *__ep; \ 453 (void)(success); (void)(failure); \ 454 (bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \ 455 __e, desired)) == __e); \ 456 }) 457 #define atomic_compare_exchange_weak_explicit(object, expected, \ 458 desired, success, failure) \ 459 atomic_compare_exchange_strong_explicit(object, expected, \ 460 desired, success, failure) 461 #ifdef __HAS_BUILTIN_SYNC_SWAP 462 /* Clang provides a full-barrier atomic exchange - use it if available. */ 463 #define atomic_exchange_explicit(object, desired, order) \ 464 ((void)(order), __sync_swap(&(object)->__val, desired)) 465 #else 466 /* 467 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in 468 * practice it is usually a full barrier) so we need an explicit barrier before 469 * it. 470 */ 471 #define atomic_exchange_explicit(object, desired, order) \ 472 __extension__ ({ \ 473 __typeof__(object) __o = (object); \ 474 __typeof__(desired) __d = (desired); \ 475 (void)(order); \ 476 __sync_synchronize(); \ 477 __sync_lock_test_and_set(&(__o)->__val, __d); \ 478 }) 479 #endif 480 #define atomic_fetch_add_explicit(object, operand, order) \ 481 ((void)(order), __sync_fetch_and_add(&(object)->__val, \ 482 __atomic_apply_stride(object, operand))) 483 #define atomic_fetch_and_explicit(object, operand, order) \ 484 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand)) 485 #define atomic_fetch_or_explicit(object, operand, order) \ 486 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand)) 487 #define atomic_fetch_sub_explicit(object, operand, order) \ 488 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \ 489 __atomic_apply_stride(object, operand))) 490 #define atomic_fetch_xor_explicit(object, operand, order) \ 491 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand)) 492 #define atomic_load_explicit(object, order) \ 493 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0)) 494 #define atomic_store_explicit(object, desired, order) \ 495 ((void)atomic_exchange_explicit(object, desired, order)) 496 #endif 497 498 /* 499 * Convenience functions. 500 * 501 * Don't provide these in kernel space. In kernel space, we should be 502 * disciplined enough to always provide explicit barriers. 503 */ 504 505 #ifndef _KERNEL 506 #define atomic_compare_exchange_strong(object, expected, desired) \ 507 atomic_compare_exchange_strong_explicit(object, expected, \ 508 desired, memory_order_seq_cst, memory_order_seq_cst) 509 #define atomic_compare_exchange_weak(object, expected, desired) \ 510 atomic_compare_exchange_weak_explicit(object, expected, \ 511 desired, memory_order_seq_cst, memory_order_seq_cst) 512 #define atomic_exchange(object, desired) \ 513 atomic_exchange_explicit(object, desired, memory_order_seq_cst) 514 #define atomic_fetch_add(object, operand) \ 515 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst) 516 #define atomic_fetch_and(object, operand) \ 517 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst) 518 #define atomic_fetch_or(object, operand) \ 519 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst) 520 #define atomic_fetch_sub(object, operand) \ 521 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst) 522 #define atomic_fetch_xor(object, operand) \ 523 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst) 524 #define atomic_load(object) \ 525 atomic_load_explicit(object, memory_order_seq_cst) 526 #define atomic_store(object, desired) \ 527 atomic_store_explicit(object, desired, memory_order_seq_cst) 528 #endif /* !_KERNEL */ 529 530 /* 531 * 7.17.8 Atomic flag type and operations. 532 * 533 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some 534 * kind of compiler built-in type we could use? 535 */ 536 537 typedef struct { 538 atomic_bool __flag; 539 } atomic_flag; 540 541 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(false) } 542 543 static __inline bool 544 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 545 memory_order __order) 546 { 547 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 548 } 549 550 static __inline void 551 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 552 { 553 554 atomic_store_explicit(&__object->__flag, 0, __order); 555 } 556 557 #ifndef _KERNEL 558 static __inline bool 559 atomic_flag_test_and_set(volatile atomic_flag *__object) 560 { 561 562 return (atomic_flag_test_and_set_explicit(__object, 563 memory_order_seq_cst)); 564 } 565 566 static __inline void 567 atomic_flag_clear(volatile atomic_flag *__object) 568 { 569 570 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 571 } 572 #endif /* !_KERNEL */ 573 574 #endif /* <atomic> unavailable */ 575 576 #endif /* !_STDATOMIC_H_ */ 577
