src/util/u_atomic.h

   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 #ifndef U_ATOMIC_H
  10 #define U_ATOMIC_H
  11
  12 #include <stdbool.h>
  13
  14 /* Favor OS-provided implementations.
  15  *
  16  * Where no OS-provided implementation is available, fall back to
  17  * locally coded assembly, compiler intrinsic or ultimately a
  18  * mutex-based implementation.
  19  */
  20 #if defined(__sun)
  21 #define PIPE_ATOMIC_OS_SOLARIS
  22 #elif defined(_MSC_VER)
  23 #define PIPE_ATOMIC_MSVC_INTRINSIC
  24 #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 401)
  25 #define PIPE_ATOMIC_GCC_INTRINSIC
  26 #else
  27 #error "Unsupported platform"
  28 #endif
  29
  30
  31 /* Implementation using GCC-provided synchronization intrinsics
  32  */
  33 #if defined(PIPE_ATOMIC_GCC_INTRINSIC)
  34
  35 #define PIPE_ATOMIC "GCC Sync Intrinsics"
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  42 #define p_atomic_read(_v) (*(_v))
  43
  44 static inline boolean
  45 p_atomic_dec_zero(int32_t *v)
  46 {
  47    return (__sync_sub_and_fetch(v, 1) == 0);
  48 }
  49
  50 static inline void
  51 p_atomic_inc(int32_t *v)
  52 {
  53    (void) __sync_add_and_fetch(v, 1);
  54 }
  55
  56 static inline void
  57 p_atomic_dec(int32_t *v)
  58 {
  59    (void) __sync_sub_and_fetch(v, 1);
  60 }
  61
  62 static inline int32_t
  63 p_atomic_inc_return(int32_t *v)
  64 {
  65    return __sync_add_and_fetch(v, 1);
  66 }
  67
  68 static inline int32_t
  69 p_atomic_dec_return(int32_t *v)
  70 {
  71    return __sync_sub_and_fetch(v, 1);
  72 }
  73
  74 static inline int32_t
  75 p_atomic_cmpxchg(int32_t *v, int32_t old, int32_t _new)
  76 {
  77    return __sync_val_compare_and_swap(v, old, _new);
  78 }
  79
  80 #ifdef __cplusplus
  81 }
  82 #endif
  83
  84 #endif
  85
  86
  87
  88 /* Unlocked version for single threaded environments, such as some
  89  * windows kernel modules.
  90  */
  91 #if defined(PIPE_ATOMIC_OS_UNLOCKED)
  92
  93 #define PIPE_ATOMIC "Unlocked"
  94
  95 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  96 #define p_atomic_read(_v) (*(_v))
  97 #define p_atomic_dec_zero(_v) ((bool) --(*(_v)))
  98 #define p_atomic_inc(_v) ((void) (*(_v))++)
  99 #define p_atomic_dec(_v) ((void) (*(_v))--)
 100 #define p_atomic_inc_return(_v) ((*(_v))++)
 101 #define p_atomic_dec_return(_v) ((*(_v))--)
 102 #define p_atomic_cmpxchg(_v, old, _new) (*(_v) == old ? *(_v) = (_new) : *(_v))
 103
 104 #endif
 105
 106
 107 #if defined(PIPE_ATOMIC_MSVC_INTRINSIC)
 108
 109 #define PIPE_ATOMIC "MSVC Intrinsics"
 110
 111 #include <intrin.h>
 112
 113 #pragma intrinsic(_InterlockedIncrement)
 114 #pragma intrinsic(_InterlockedDecrement)
 115 #pragma intrinsic(_InterlockedCompareExchange)
 116
 117 #ifdef __cplusplus
 118 extern "C" {
 119 #endif
 120
 121 #define p_atomic_set(_v, _i) (*(_v) = (_i))
 122 #define p_atomic_read(_v) (*(_v))
 123
 124 static inline bool
 125 p_atomic_dec_zero(int32_t *v)
 126 {
 127    return _InterlockedDecrement((long *)v) == 0;
 128 }
 129
 130 static inline void
 131 p_atomic_inc(int32_t *v)
 132 {
 133    _InterlockedIncrement((long *)v);
 134 }
 135
 136 static inline int32_t
 137 p_atomic_inc_return(int32_t *v)
 138 {
 139    return _InterlockedIncrement((long *)v);
 140 }
 141
 142 static inline void
 143 p_atomic_dec(int32_t *v)
 144 {
 145    _InterlockedDecrement((long *)v);
 146 }
 147
 148 static inline int32_t
 149 p_atomic_dec_return(int32_t *v)
 150 {
 151    return _InterlockedDecrement((long *)v);
 152 }
 153
 154 static inline int32_t
 155 p_atomic_cmpxchg(int32_t *v, int32_t old, int32_t _new)
 156 {
 157    return _InterlockedCompareExchange((long *)v, _new, old);
 158 }
 159
 160 #ifdef __cplusplus
 161 }
 162 #endif
 163
 164 #endif
 165
 166 #if defined(PIPE_ATOMIC_OS_SOLARIS)
 167
 168 #define PIPE_ATOMIC "Solaris OS atomic functions"
 169
 170 #include <atomic.h>
 171
 172 #ifdef __cplusplus
 173 extern "C" {
 174 #endif
 175
 176 #define p_atomic_set(_v, _i) (*(_v) = (_i))
 177 #define p_atomic_read(_v) (*(_v))
 178
 179 static inline bool
 180 p_atomic_dec_zero(int32_t *v)
 181 {
 182    uint32_t n = atomic_dec_32_nv((uint32_t *) v);
 183
 184    return n != 0;
 185 }
 186
 187 #define p_atomic_inc(_v) atomic_inc_32((uint32_t *) _v)
 188 #define p_atomic_dec(_v) atomic_dec_32((uint32_t *) _v)
 189 #define p_atomic_inc_return(_v) atomic_inc_32_nv((uint32_t *) _v)
 190 #define p_atomic_dec_return(_v) atomic_dec_32_nv((uint32_t *) _v)
 191
 192 #define p_atomic_cmpxchg(_v, _old, _new) \
 193         atomic_cas_32( (uint32_t *) _v, (uint32_t) _old, (uint32_t) _new)
 194
 195 #ifdef __cplusplus
 196 }
 197 #endif
 198
 199 #endif
 200
 201
 202 #ifndef PIPE_ATOMIC
 203 #error "No pipe_atomic implementation selected"
 204 #endif
 205
 206
 207
 208 #endif /* U_ATOMIC_H */