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 #if defined(__GNUC__) && !defined(__GNUC_PREREQ) 36 /* Duplicate definition here, since the mingw sys/cdefs.h omits the */ 37 /* definition, and this needs to be usable there. */ 38 #define __GNUC_PREREQ(x, y) \ 39 ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) || (__GNUC__ > (x))) 40 #endif /* __GNUC__ && ... */ 41 42 #if defined(__cplusplus) && __cplusplus >= 201103L && defined(_USING_LIBCXX) 43 # ifdef __clang__ 44 # if __has_feature(cxx_atomic) 45 # define _STDATOMIC_HAVE_ATOMIC 46 # endif 47 # else /* gcc */ 48 # if __GNUC_PREREQ(4, 7) 49 # define _STDATOMIC_HAVE_ATOMIC 50 # endif 51 # endif 52 #endif 53 54 #ifdef _STDATOMIC_HAVE_ATOMIC 55 56 /* We have a usable C++ <atomic>; use it instead. */ 57 58 #include <atomic> 59 60 #undef _Atomic 61 /* Also defined by <atomic> for gcc. But not used in macros. */ 62 /* Also a clang intrinsic. */ 63 /* Should not be used by client code before this file is */ 64 /* included. The definitions in <atomic> themselves see */ 65 /* the old definition, as they should. */ 66 /* Client code sees the following definition. */ 67 68 #define _Atomic(t) std::atomic<t> 69 70 using std::atomic_is_lock_free; 71 using std::atomic_init; 72 using std::atomic_store; 73 using std::atomic_store_explicit; 74 using std::atomic_load; 75 using std::atomic_load_explicit; 76 using std::atomic_exchange; 77 using std::atomic_exchange_explicit; 78 using std::atomic_compare_exchange_strong; 79 using std::atomic_compare_exchange_strong_explicit; 80 using std::atomic_compare_exchange_weak; 81 using std::atomic_compare_exchange_weak_explicit; 82 using std::atomic_fetch_add; 83 using std::atomic_fetch_add_explicit; 84 using std::atomic_fetch_sub; 85 using std::atomic_fetch_sub_explicit; 86 using std::atomic_fetch_or; 87 using std::atomic_fetch_or_explicit; 88 using std::atomic_fetch_xor; 89 using std::atomic_fetch_xor_explicit; 90 using std::atomic_fetch_and; 91 using std::atomic_fetch_and_explicit; 92 using std::atomic_thread_fence; 93 using std::atomic_signal_fence; 94 95 using std::memory_order; 96 using std::memory_order_relaxed; 97 using std::memory_order_consume; 98 using std::memory_order_acquire; 99 using std::memory_order_release; 100 using std::memory_order_acq_rel; 101 using std::memory_order_seq_cst; 102 103 using std::atomic_bool; 104 using std::atomic_char; 105 using std::atomic_schar; 106 using std::atomic_uchar; 107 using std::atomic_short; 108 using std::atomic_ushort; 109 using std::atomic_int; 110 using std::atomic_uint; 111 using std::atomic_long; 112 using std::atomic_ulong; 113 using std::atomic_llong; 114 using std::atomic_ullong; 115 using std::atomic_char16_t; 116 using std::atomic_char32_t; 117 using std::atomic_wchar_t; 118 using std::atomic_int_least8_t; 119 using std::atomic_uint_least8_t; 120 using std::atomic_int_least16_t; 121 using std::atomic_uint_least16_t; 122 using std::atomic_int_least32_t; 123 using std::atomic_uint_least32_t; 124 using std::atomic_int_least64_t; 125 using std::atomic_uint_least64_t; 126 using std::atomic_int_fast8_t; 127 using std::atomic_uint_fast8_t; 128 using std::atomic_int_fast16_t; 129 using std::atomic_uint_fast16_t; 130 using std::atomic_int_fast32_t; 131 using std::atomic_uint_fast32_t; 132 using std::atomic_int_fast64_t; 133 using std::atomic_uint_fast64_t; 134 using std::atomic_intptr_t; 135 using std::atomic_uintptr_t; 136 using std::atomic_size_t; 137 using std::atomic_ptrdiff_t; 138 using std::atomic_intmax_t; 139 using std::atomic_uintmax_t; 140 141 #else /* <atomic> unavailable, possibly because this is C, not C++ */ 142 143 #include <sys/types.h> 144 #include <stdbool.h> 145 146 /* 147 * C: Do it ourselves. 148 * Note that the runtime representation defined here should be compatible 149 * with the C++ one, i.e. an _Atomic(T) needs to contain the same 150 * bits as a T. 151 */ 152 153 #include <stddef.h> /* For ptrdiff_t. */ 154 #include <stdint.h> /* TODO: Should pollute namespace less. */ 155 #if __STDC_VERSION__ >= 201112L 156 # include <uchar.h> /* For char16_t and char32_t. */ 157 #endif 158 159 #ifdef __clang__ 160 # if __has_extension(c_atomic) || __has_extension(cxx_atomic) 161 # define __CLANG_ATOMICS 162 # else 163 # error "stdatomic.h does not support your compiler" 164 # endif 165 # if __has_builtin(__sync_swap) 166 # define __HAS_BUILTIN_SYNC_SWAP 167 # endif 168 #else 169 # if __GNUC_PREREQ(4, 7) 170 # define __GNUC_ATOMICS 171 # else 172 # define __SYNC_ATOMICS 173 # ifdef __cplusplus 174 # define __ATOMICS_AVOID_DOT_INIT 175 # endif 176 # endif 177 #endif 178 179 /* 180 * 7.17.1 Atomic lock-free macros. 181 */ 182 183 #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE 184 #define ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_BOOL_LOCK_FREE 185 #elif defined(__SYNC_ATOMICS) 186 #define ATOMIC_BOOL_LOCK_FREE 2 /* For all modern platforms */ 187 #endif 188 #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE 189 #define ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE 190 #elif defined(__SYNC_ATOMICS) 191 #define ATOMIC_CHAR_LOCK_FREE 2 192 #endif 193 #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE 194 #define ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE 195 #elif defined(__SYNC_ATOMICS) 196 #define ATOMIC_CHAR16_T_LOCK_FREE 2 197 #endif 198 #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE 199 #define ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE 200 #elif defined(__SYNC_ATOMICS) 201 #define ATOMIC_CHAR32_T_LOCK_FREE 2 202 #endif 203 #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE 204 #define ATOMIC_WCHAR_T_LOCK_FREE __GCC_ATOMIC_WCHAR_T_LOCK_FREE 205 #elif defined(__SYNC_ATOMICS) 206 #define ATOMIC_WCHAR_T_LOCK_FREE 2 207 #endif 208 #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE 209 #define ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE 210 #elif defined(__SYNC_ATOMICS) 211 #define ATOMIC_SHORT_LOCK_FREE 2 212 #endif 213 #ifdef __GCC_ATOMIC_INT_LOCK_FREE 214 #define ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE 215 #elif defined(__SYNC_ATOMICS) 216 #define ATOMIC_INT_LOCK_FREE 2 217 #endif 218 #ifdef __GCC_ATOMIC_LONG_LOCK_FREE 219 #define ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE 220 #elif defined(__SYNC_ATOMICS) 221 #define ATOMIC_LONG_LOCK_FREE 2 222 #endif 223 #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE 224 #define ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE 225 #elif defined(__SYNC_ATOMICS) 226 #define ATOMIC_LLONG_LOCK_FREE 1 /* maybe */ 227 #endif 228 #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE 229 #define ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE 230 #elif defined(__SYNC_ATOMICS) 231 #define ATOMIC_POINTER_LOCK_FREE 2 232 #endif 233 234 /* 235 * 7.17.2 Initialization. 236 */ 237 238 #if defined(__CLANG_ATOMICS) 239 #define ATOMIC_VAR_INIT(value) (value) 240 #define atomic_init(obj, value) __c11_atomic_init(obj, value) 241 #else 242 #ifdef __ATOMICS_AVOID_DOT_INIT 243 #define ATOMIC_VAR_INIT(value) { value } 244 #else 245 #define ATOMIC_VAR_INIT(value) { .__val = (value) } 246 #endif 247 #define atomic_init(obj, value) ((void)((obj)->__val = (value))) 248 #endif 249 250 /* 251 * Clang and recent GCC both provide predefined macros for the memory 252 * orderings. If we are using a compiler that doesn't define them, use the 253 * clang values - these will be ignored in the fallback path. 254 */ 255 256 #ifndef __ATOMIC_RELAXED 257 #define __ATOMIC_RELAXED 0 258 #endif 259 #ifndef __ATOMIC_CONSUME 260 #define __ATOMIC_CONSUME 1 261 #endif 262 #ifndef __ATOMIC_ACQUIRE 263 #define __ATOMIC_ACQUIRE 2 264 #endif 265 #ifndef __ATOMIC_RELEASE 266 #define __ATOMIC_RELEASE 3 267 #endif 268 #ifndef __ATOMIC_ACQ_REL 269 #define __ATOMIC_ACQ_REL 4 270 #endif 271 #ifndef __ATOMIC_SEQ_CST 272 #define __ATOMIC_SEQ_CST 5 273 #endif 274 275 /* 276 * 7.17.3 Order and consistency. 277 * 278 * The memory_order_* constants that denote the barrier behaviour of the 279 * atomic operations. 280 * The enum values must be identical to those used by the 281 * C++ <atomic> header. 282 */ 283 284 typedef enum { 285 memory_order_relaxed = __ATOMIC_RELAXED, 286 memory_order_consume = __ATOMIC_CONSUME, 287 memory_order_acquire = __ATOMIC_ACQUIRE, 288 memory_order_release = __ATOMIC_RELEASE, 289 memory_order_acq_rel = __ATOMIC_ACQ_REL, 290 memory_order_seq_cst = __ATOMIC_SEQ_CST 291 } memory_order; 292 293 /* 294 * 7.17.4 Fences. 295 */ 296 297 static __inline void 298 atomic_thread_fence(memory_order __order __attribute__((unused))) 299 { 300 301 #ifdef __CLANG_ATOMICS 302 __c11_atomic_thread_fence(__order); 303 #elif defined(__GNUC_ATOMICS) 304 __atomic_thread_fence(__order); 305 #else 306 __sync_synchronize(); 307 #endif 308 } 309 310 static __inline void 311 atomic_signal_fence(memory_order __order __attribute__((unused))) 312 { 313 314 #ifdef __CLANG_ATOMICS 315 __c11_atomic_signal_fence(__order); 316 #elif defined(__GNUC_ATOMICS) 317 __atomic_signal_fence(__order); 318 #else 319 __asm volatile ("" ::: "memory"); 320 #endif 321 } 322 323 /* 324 * 7.17.5 Lock-free property. 325 */ 326 327 #if defined(_KERNEL) 328 /* Atomics in kernelspace are always lock-free. */ 329 #define atomic_is_lock_free(obj) \ 330 ((void)(obj), (_Bool)1) 331 #elif defined(__CLANG_ATOMICS) 332 #define atomic_is_lock_free(obj) \ 333 __c11_atomic_is_lock_free(sizeof(*(obj))) 334 #elif defined(__GNUC_ATOMICS) 335 #define atomic_is_lock_free(obj) \ 336 __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) 337 #else 338 #define atomic_is_lock_free(obj) \ 339 ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) 340 #endif 341 342 /* 343 * 7.17.6 Atomic integer types. 344 */ 345 346 #ifndef __CLANG_ATOMICS 347 /* 348 * No native support for _Atomic(). Place object in structure to prevent 349 * most forms of direct non-atomic access. 350 */ 351 #define _Atomic(T) struct { T volatile __val; } 352 #endif 353 354 typedef _Atomic(bool) atomic_bool; 355 typedef _Atomic(char) atomic_char; 356 typedef _Atomic(signed char) atomic_schar; 357 typedef _Atomic(unsigned char) atomic_uchar; 358 typedef _Atomic(short) atomic_short; 359 typedef _Atomic(unsigned short) atomic_ushort; 360 typedef _Atomic(int) atomic_int; 361 typedef _Atomic(unsigned int) atomic_uint; 362 typedef _Atomic(long) atomic_long; 363 typedef _Atomic(unsigned long) atomic_ulong; 364 typedef _Atomic(long long) atomic_llong; 365 typedef _Atomic(unsigned long long) atomic_ullong; 366 #if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L 367 typedef _Atomic(char16_t) atomic_char16_t; 368 typedef _Atomic(char32_t) atomic_char32_t; 369 #endif 370 typedef _Atomic(wchar_t) atomic_wchar_t; 371 typedef _Atomic(int_least8_t) atomic_int_least8_t; 372 typedef _Atomic(uint_least8_t) atomic_uint_least8_t; 373 typedef _Atomic(int_least16_t) atomic_int_least16_t; 374 typedef _Atomic(uint_least16_t) atomic_uint_least16_t; 375 typedef _Atomic(int_least32_t) atomic_int_least32_t; 376 typedef _Atomic(uint_least32_t) atomic_uint_least32_t; 377 typedef _Atomic(int_least64_t) atomic_int_least64_t; 378 typedef _Atomic(uint_least64_t) atomic_uint_least64_t; 379 typedef _Atomic(int_fast8_t) atomic_int_fast8_t; 380 typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t; 381 typedef _Atomic(int_fast16_t) atomic_int_fast16_t; 382 typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t; 383 typedef _Atomic(int_fast32_t) atomic_int_fast32_t; 384 typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t; 385 typedef _Atomic(int_fast64_t) atomic_int_fast64_t; 386 typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t; 387 typedef _Atomic(intptr_t) atomic_intptr_t; 388 typedef _Atomic(uintptr_t) atomic_uintptr_t; 389 typedef _Atomic(size_t) atomic_size_t; 390 typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t; 391 typedef _Atomic(intmax_t) atomic_intmax_t; 392 typedef _Atomic(uintmax_t) atomic_uintmax_t; 393 394 /* 395 * 7.17.7 Operations on atomic types. 396 */ 397 398 /* 399 * Compiler-specific operations. 400 */ 401 402 #if defined(__CLANG_ATOMICS) 403 #define atomic_compare_exchange_strong_explicit(object, expected, \ 404 desired, success, failure) \ 405 __c11_atomic_compare_exchange_strong(object, expected, desired, \ 406 success, failure) 407 #define atomic_compare_exchange_weak_explicit(object, expected, \ 408 desired, success, failure) \ 409 __c11_atomic_compare_exchange_weak(object, expected, desired, \ 410 success, failure) 411 #define atomic_exchange_explicit(object, desired, order) \ 412 __c11_atomic_exchange(object, desired, order) 413 #define atomic_fetch_add_explicit(object, operand, order) \ 414 __c11_atomic_fetch_add(object, operand, order) 415 #define atomic_fetch_and_explicit(object, operand, order) \ 416 __c11_atomic_fetch_and(object, operand, order) 417 #define atomic_fetch_or_explicit(object, operand, order) \ 418 __c11_atomic_fetch_or(object, operand, order) 419 #define atomic_fetch_sub_explicit(object, operand, order) \ 420 __c11_atomic_fetch_sub(object, operand, order) 421 #define atomic_fetch_xor_explicit(object, operand, order) \ 422 __c11_atomic_fetch_xor(object, operand, order) 423 #define atomic_load_explicit(object, order) \ 424 __c11_atomic_load(object, order) 425 #define atomic_store_explicit(object, desired, order) \ 426 __c11_atomic_store(object, desired, order) 427 #elif defined(__GNUC_ATOMICS) 428 #define atomic_compare_exchange_strong_explicit(object, expected, \ 429 desired, success, failure) \ 430 __atomic_compare_exchange_n(&(object)->__val, expected, \ 431 desired, 0, success, failure) 432 #define atomic_compare_exchange_weak_explicit(object, expected, \ 433 desired, success, failure) \ 434 __atomic_compare_exchange_n(&(object)->__val, expected, \ 435 desired, 1, success, failure) 436 #define atomic_exchange_explicit(object, desired, order) \ 437 __atomic_exchange_n(&(object)->__val, desired, order) 438 #define atomic_fetch_add_explicit(object, operand, order) \ 439 __atomic_fetch_add(&(object)->__val, operand, order) 440 #define atomic_fetch_and_explicit(object, operand, order) \ 441 __atomic_fetch_and(&(object)->__val, operand, order) 442 #define atomic_fetch_or_explicit(object, operand, order) \ 443 __atomic_fetch_or(&(object)->__val, operand, order) 444 #define atomic_fetch_sub_explicit(object, operand, order) \ 445 __atomic_fetch_sub(&(object)->__val, operand, order) 446 #define atomic_fetch_xor_explicit(object, operand, order) \ 447 __atomic_fetch_xor(&(object)->__val, operand, order) 448 #define atomic_load_explicit(object, order) \ 449 __atomic_load_n(&(object)->__val, order) 450 #define atomic_store_explicit(object, desired, order) \ 451 __atomic_store_n(&(object)->__val, desired, order) 452 #else 453 #define __atomic_apply_stride(object, operand) \ 454 (((__typeof__((object)->__val))0) + (operand)) 455 #define atomic_compare_exchange_strong_explicit(object, expected, \ 456 desired, success, failure) __extension__ ({ \ 457 __typeof__(expected) __ep = (expected); \ 458 __typeof__(*__ep) __e = *__ep; \ 459 (void)(success); (void)(failure); \ 460 (bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val, \ 461 __e, desired)) == __e); \ 462 }) 463 #define atomic_compare_exchange_weak_explicit(object, expected, \ 464 desired, success, failure) \ 465 atomic_compare_exchange_strong_explicit(object, expected, \ 466 desired, success, failure) 467 #ifdef __HAS_BUILTIN_SYNC_SWAP 468 /* Clang provides a full-barrier atomic exchange - use it if available. */ 469 #define atomic_exchange_explicit(object, desired, order) \ 470 ((void)(order), __sync_swap(&(object)->__val, desired)) 471 #else 472 /* 473 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in 474 * practice it is usually a full barrier) so we need an explicit barrier before 475 * it. 476 */ 477 #define atomic_exchange_explicit(object, desired, order) \ 478 __extension__ ({ \ 479 __typeof__(object) __o = (object); \ 480 __typeof__(desired) __d = (desired); \ 481 (void)(order); \ 482 __sync_synchronize(); \ 483 __sync_lock_test_and_set(&(__o)->__val, __d); \ 484 }) 485 #endif 486 #define atomic_fetch_add_explicit(object, operand, order) \ 487 ((void)(order), __sync_fetch_and_add(&(object)->__val, \ 488 __atomic_apply_stride(object, operand))) 489 #define atomic_fetch_and_explicit(object, operand, order) \ 490 ((void)(order), __sync_fetch_and_and(&(object)->__val, operand)) 491 #define atomic_fetch_or_explicit(object, operand, order) \ 492 ((void)(order), __sync_fetch_and_or(&(object)->__val, operand)) 493 #define atomic_fetch_sub_explicit(object, operand, order) \ 494 ((void)(order), __sync_fetch_and_sub(&(object)->__val, \ 495 __atomic_apply_stride(object, operand))) 496 #define atomic_fetch_xor_explicit(object, operand, order) \ 497 ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand)) 498 #define atomic_load_explicit(object, order) \ 499 ((void)(order), __sync_fetch_and_add(&(object)->__val, 0)) 500 #define atomic_store_explicit(object, desired, order) \ 501 ((void)atomic_exchange_explicit(object, desired, order)) 502 #endif 503 504 /* 505 * Convenience functions. 506 * 507 * Don't provide these in kernel space. In kernel space, we should be 508 * disciplined enough to always provide explicit barriers. 509 */ 510 511 #ifndef _KERNEL 512 #define atomic_compare_exchange_strong(object, expected, desired) \ 513 atomic_compare_exchange_strong_explicit(object, expected, \ 514 desired, memory_order_seq_cst, memory_order_seq_cst) 515 #define atomic_compare_exchange_weak(object, expected, desired) \ 516 atomic_compare_exchange_weak_explicit(object, expected, \ 517 desired, memory_order_seq_cst, memory_order_seq_cst) 518 #define atomic_exchange(object, desired) \ 519 atomic_exchange_explicit(object, desired, memory_order_seq_cst) 520 #define atomic_fetch_add(object, operand) \ 521 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst) 522 #define atomic_fetch_and(object, operand) \ 523 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst) 524 #define atomic_fetch_or(object, operand) \ 525 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst) 526 #define atomic_fetch_sub(object, operand) \ 527 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst) 528 #define atomic_fetch_xor(object, operand) \ 529 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst) 530 #define atomic_load(object) \ 531 atomic_load_explicit(object, memory_order_seq_cst) 532 #define atomic_store(object, desired) \ 533 atomic_store_explicit(object, desired, memory_order_seq_cst) 534 #endif /* !_KERNEL */ 535 536 /* 537 * 7.17.8 Atomic flag type and operations. 538 * 539 * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some 540 * kind of compiler built-in type we could use? 541 */ 542 543 typedef struct { 544 atomic_bool __flag; 545 } atomic_flag; 546 547 #define ATOMIC_FLAG_INIT { ATOMIC_VAR_INIT(false) } 548 549 static __inline bool 550 atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, 551 memory_order __order) 552 { 553 return (atomic_exchange_explicit(&__object->__flag, 1, __order)); 554 } 555 556 static __inline void 557 atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) 558 { 559 560 atomic_store_explicit(&__object->__flag, 0, __order); 561 } 562 563 #ifndef _KERNEL 564 static __inline bool 565 atomic_flag_test_and_set(volatile atomic_flag *__object) 566 { 567 568 return (atomic_flag_test_and_set_explicit(__object, 569 memory_order_seq_cst)); 570 } 571 572 static __inline void 573 atomic_flag_clear(volatile atomic_flag *__object) 574 { 575 576 atomic_flag_clear_explicit(__object, memory_order_seq_cst); 577 } 578 #endif /* !_KERNEL */ 579 580 #endif /* <atomic> unavailable */ 581 582 #endif /* !_STDATOMIC_H_ */ 583
