1/** 2 * Many similar implementations exist. See for example libwsbm 3 * or the linux kernel include/atomic.h 4 * 5 * No copyright claimed on this file. 6 * 7 */ 8 9#include "no_extern_c.h" 10 11#ifndef U_ATOMIC_H 12#define U_ATOMIC_H 13 14#include <stdbool.h> 15 16/* Favor OS-provided implementations. 17 * 18 * Where no OS-provided implementation is available, fall back to 19 * locally coded assembly, compiler intrinsic or ultimately a 20 * mutex-based implementation. 21 */ 22#if defined(__sun) 23#define PIPE_ATOMIC_OS_SOLARIS 24#elif defined(_MSC_VER) 25#define PIPE_ATOMIC_MSVC_INTRINSIC 26#elif defined(__GNUC__) 27#define PIPE_ATOMIC_GCC_INTRINSIC 28#else 29#error "Unsupported platform" 30#endif 31 32 33/* Implementation using GCC-provided synchronization intrinsics 34 */ 35#if defined(PIPE_ATOMIC_GCC_INTRINSIC) 36 37#define PIPE_ATOMIC "GCC Sync Intrinsics" 38 39#if defined(USE_GCC_ATOMIC_BUILTINS) 40 41/* The builtins with explicit memory model are available since GCC 4.7. */ 42#define p_atomic_set(_v, _i) __atomic_store_n((_v), (_i), __ATOMIC_RELEASE) 43#define p_atomic_read(_v) __atomic_load_n((_v), __ATOMIC_ACQUIRE) 44#define p_atomic_dec_zero(v) (__atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL) == 0) 45#define p_atomic_inc(v) (void) __atomic_add_fetch((v), 1, __ATOMIC_ACQ_REL) 46#define p_atomic_dec(v) (void) __atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL) 47#define p_atomic_add(v, i) (void) __atomic_add_fetch((v), (i), __ATOMIC_ACQ_REL) 48#define p_atomic_inc_return(v) __atomic_add_fetch((v), 1, __ATOMIC_ACQ_REL) 49#define p_atomic_dec_return(v) __atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL) 50 51#else 52 53#define p_atomic_set(_v, _i) (*(_v) = (_i)) 54#define p_atomic_read(_v) (*(_v)) 55#define p_atomic_dec_zero(v) (__sync_sub_and_fetch((v), 1) == 0) 56#define p_atomic_inc(v) (void) __sync_add_and_fetch((v), 1) 57#define p_atomic_dec(v) (void) __sync_sub_and_fetch((v), 1) 58#define p_atomic_add(v, i) (void) __sync_add_and_fetch((v), (i)) 59#define p_atomic_inc_return(v) __sync_add_and_fetch((v), 1) 60#define p_atomic_dec_return(v) __sync_sub_and_fetch((v), 1) 61 62#endif 63 64/* There is no __atomic_* compare and exchange that returns the current value. 65 * Also, GCC 5.4 seems unable to optimize a compound statement expression that 66 * uses an additional stack variable with __atomic_compare_exchange[_n]. 67 */ 68#define p_atomic_cmpxchg(v, old, _new) \ 69 __sync_val_compare_and_swap((v), (old), (_new)) 70 71#endif 72 73 74 75/* Unlocked version for single threaded environments, such as some 76 * windows kernel modules. 77 */ 78#if defined(PIPE_ATOMIC_OS_UNLOCKED) 79 80#define PIPE_ATOMIC "Unlocked" 81 82#define p_atomic_set(_v, _i) (*(_v) = (_i)) 83#define p_atomic_read(_v) (*(_v)) 84#define p_atomic_dec_zero(_v) (p_atomic_dec_return(_v) == 0) 85#define p_atomic_inc(_v) ((void) p_atomic_inc_return(_v)) 86#define p_atomic_dec(_v) ((void) p_atomic_dec_return(_v)) 87#define p_atomic_add(_v, _i) (*(_v) = *(_v) + (_i)) 88#define p_atomic_inc_return(_v) (++(*(_v))) 89#define p_atomic_dec_return(_v) (--(*(_v))) 90#define p_atomic_cmpxchg(_v, _old, _new) (*(_v) == (_old) ? (*(_v) = (_new), (_old)) : *(_v)) 91 92#endif 93 94 95#if defined(PIPE_ATOMIC_MSVC_INTRINSIC) 96 97#define PIPE_ATOMIC "MSVC Intrinsics" 98 99/* We use the Windows header's Interlocked*64 functions instead of the 100 * _Interlocked*64 intrinsics wherever we can, as support for the latter varies 101 * with target CPU, whereas Windows headers take care of all portability 102 * issues: using intrinsics where available, falling back to library 103 * implementations where not. 104 */ 105#ifndef WIN32_LEAN_AND_MEAN 106#define WIN32_LEAN_AND_MEAN 1 107#endif 108#include <windows.h> 109#include <intrin.h> 110#include <assert.h> 111 112/* MSVC supports decltype keyword, but it's only supported on C++ and doesn't 113 * quite work here; and if a C++-only solution is worthwhile, then it would be 114 * better to use templates / function overloading, instead of decltype magic. 115 * Therefore, we rely on implicit casting to LONGLONG for the functions that return 116 */ 117 118#define p_atomic_set(_v, _i) (*(_v) = (_i)) 119#define p_atomic_read(_v) (*(_v)) 120 121#define p_atomic_dec_zero(_v) \ 122 (p_atomic_dec_return(_v) == 0) 123 124#define p_atomic_inc(_v) \ 125 ((void) p_atomic_inc_return(_v)) 126 127#define p_atomic_inc_return(_v) (\ 128 sizeof *(_v) == sizeof(short) ? _InterlockedIncrement16((short *) (_v)) : \ 129 sizeof *(_v) == sizeof(long) ? _InterlockedIncrement ((long *) (_v)) : \ 130 sizeof *(_v) == sizeof(__int64) ? InterlockedIncrement64 ((__int64 *)(_v)) : \ 131 (assert(!"should not get here"), 0)) 132 133#define p_atomic_dec(_v) \ 134 ((void) p_atomic_dec_return(_v)) 135 136#define p_atomic_dec_return(_v) (\ 137 sizeof *(_v) == sizeof(short) ? _InterlockedDecrement16((short *) (_v)) : \ 138 sizeof *(_v) == sizeof(long) ? _InterlockedDecrement ((long *) (_v)) : \ 139 sizeof *(_v) == sizeof(__int64) ? InterlockedDecrement64 ((__int64 *)(_v)) : \ 140 (assert(!"should not get here"), 0)) 141 142#define p_atomic_add(_v, _i) (\ 143 sizeof *(_v) == sizeof(char) ? _InterlockedExchangeAdd8 ((char *) (_v), (_i)) : \ 144 sizeof *(_v) == sizeof(short) ? _InterlockedExchangeAdd16((short *) (_v), (_i)) : \ 145 sizeof *(_v) == sizeof(long) ? _InterlockedExchangeAdd ((long *) (_v), (_i)) : \ 146 sizeof *(_v) == sizeof(__int64) ? InterlockedExchangeAdd64((__int64 *)(_v), (_i)) : \ 147 (assert(!"should not get here"), 0)) 148 149#define p_atomic_cmpxchg(_v, _old, _new) (\ 150 sizeof *(_v) == sizeof(char) ? _InterlockedCompareExchange8 ((char *) (_v), (char) (_new), (char) (_old)) : \ 151 sizeof *(_v) == sizeof(short) ? _InterlockedCompareExchange16((short *) (_v), (short) (_new), (short) (_old)) : \ 152 sizeof *(_v) == sizeof(long) ? _InterlockedCompareExchange ((long *) (_v), (long) (_new), (long) (_old)) : \ 153 sizeof *(_v) == sizeof(__int64) ? InterlockedCompareExchange64 ((__int64 *)(_v), (__int64)(_new), (__int64)(_old)) : \ 154 (assert(!"should not get here"), 0)) 155 156#endif 157 158#if defined(PIPE_ATOMIC_OS_SOLARIS) 159 160#define PIPE_ATOMIC "Solaris OS atomic functions" 161 162#include <atomic.h> 163#include <assert.h> 164 165#define p_atomic_set(_v, _i) (*(_v) = (_i)) 166#define p_atomic_read(_v) (*(_v)) 167 168#define p_atomic_dec_zero(v) (\ 169 sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8_nv ((uint8_t *)(v)) == 0 : \ 170 sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) == 0 : \ 171 sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) == 0 : \ 172 sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) == 0 : \ 173 (assert(!"should not get here"), 0)) 174 175#define p_atomic_inc(v) (void) (\ 176 sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8 ((uint8_t *)(v)) : \ 177 sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16((uint16_t *)(v)) : \ 178 sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32((uint32_t *)(v)) : \ 179 sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64((uint64_t *)(v)) : \ 180 (assert(!"should not get here"), 0)) 181 182#define p_atomic_inc_return(v) ((__typeof(*v)) \ 183 sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8_nv ((uint8_t *)(v)) : \ 184 sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16_nv((uint16_t *)(v)) : \ 185 sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32_nv((uint32_t *)(v)) : \ 186 sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64_nv((uint64_t *)(v)) : \ 187 (assert(!"should not get here"), 0)) 188 189#define p_atomic_dec(v) ((void) \ 190 sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8 ((uint8_t *)(v)) : \ 191 sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16((uint16_t *)(v)) : \ 192 sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32((uint32_t *)(v)) : \ 193 sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64((uint64_t *)(v)) : \ 194 (assert(!"should not get here"), 0)) 195 196#define p_atomic_dec_return(v) ((__typeof(*v)) \ 197 sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8_nv ((uint8_t *)(v)) : \ 198 sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) : \ 199 sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) : \ 200 sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) : \ 201 (assert(!"should not get here"), 0)) 202 203#define p_atomic_add(v, i) ((void) \ 204 sizeof(*v) == sizeof(uint8_t) ? atomic_add_8 ((uint8_t *)(v), (i)) : \ 205 sizeof(*v) == sizeof(uint16_t) ? atomic_add_16((uint16_t *)(v), (i)) : \ 206 sizeof(*v) == sizeof(uint32_t) ? atomic_add_32((uint32_t *)(v), (i)) : \ 207 sizeof(*v) == sizeof(uint64_t) ? atomic_add_64((uint64_t *)(v), (i)) : \ 208 (assert(!"should not get here"), 0)) 209 210#define p_atomic_cmpxchg(v, old, _new) ((__typeof(*v)) \ 211 sizeof(*v) == sizeof(uint8_t) ? atomic_cas_8 ((uint8_t *)(v), (uint8_t )(old), (uint8_t )(_new)) : \ 212 sizeof(*v) == sizeof(uint16_t) ? atomic_cas_16((uint16_t *)(v), (uint16_t)(old), (uint16_t)(_new)) : \ 213 sizeof(*v) == sizeof(uint32_t) ? atomic_cas_32((uint32_t *)(v), (uint32_t)(old), (uint32_t)(_new)) : \ 214 sizeof(*v) == sizeof(uint64_t) ? atomic_cas_64((uint64_t *)(v), (uint64_t)(old), (uint64_t)(_new)) : \ 215 (assert(!"should not get here"), 0)) 216 217#endif 218 219#ifndef PIPE_ATOMIC 220#error "No pipe_atomic implementation selected" 221#endif 222 223 224 225#endif /* U_ATOMIC_H */ 226