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
