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__)
  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 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  38 #define p_atomic_read(_v) (*(_v))
  39 #define p_atomic_dec_zero(v) (__sync_sub_and_fetch((v), 1) == 0)
  40 #define p_atomic_inc(v) (void) __sync_add_and_fetch((v), 1)
  41 #define p_atomic_dec(v) (void) __sync_sub_and_fetch((v), 1)
  42 #define p_atomic_inc_return(v) __sync_add_and_fetch((v), 1)
  43 #define p_atomic_dec_return(v) __sync_sub_and_fetch((v), 1)
  44 #define p_atomic_cmpxchg(v, old, _new) \
  45    __sync_val_compare_and_swap((v), (old), (_new))
  46
  47 #endif
  48
  49
  50
  51 /* Unlocked version for single threaded environments, such as some
  52  * windows kernel modules.
  53  */
  54 #if defined(PIPE_ATOMIC_OS_UNLOCKED)
  55
  56 #define PIPE_ATOMIC "Unlocked"
  57
  58 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  59 #define p_atomic_read(_v) (*(_v))
  60 #define p_atomic_dec_zero(_v) (p_atomic_dec_return(_v) == 0)
  61 #define p_atomic_inc(_v) ((void) p_atomic_inc_return(_v))
  62 #define p_atomic_dec(_v) ((void) p_atomic_dec_return(_v))
  63 #define p_atomic_inc_return(_v) (++(*(_v)))
  64 #define p_atomic_dec_return(_v) (--(*(_v)))
  65 #define p_atomic_cmpxchg(_v, _old, _new) (*(_v) == (_old) ? (*(_v) = (_new), (_old)) : *(_v))
  66
  67 #endif
  68
  69
  70 #if defined(PIPE_ATOMIC_MSVC_INTRINSIC)
  71
  72 #define PIPE_ATOMIC "MSVC Intrinsics"
  73
  74 /* We use the Windows header's Interlocked*64 functions instead of the
  75  * _Interlocked*64 intrinsics wherever we can, as support for the latter varies
  76  * with target CPU, whereas Windows headers take care of all portability
  77  * issues: using intrinsics where available, falling back to library
  78  * implementations where not.
  79  */
  80 #ifndef WIN32_LEAN_AND_MEAN
  81 #define WIN32_LEAN_AND_MEAN 1
  82 #endif
  83 #include <windows.h>
  84 #include <intrin.h>
  85 #include <assert.h>
  86
  87 #pragma intrinsic(_InterlockedCompareExchange8)
  88
  89 /* MSVC supports decltype keyword, but it's only supported on C++ and doesn't
  90  * quite work here; and if a C++-only solution is worthwhile, then it would be
  91  * better to use templates / function overloading, instead of decltype magic.
  92  * Therefore, we rely on implicit casting to LONGLONG for the functions that return
  93  */
  94
  95 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  96 #define p_atomic_read(_v) (*(_v))
  97
  98 #define p_atomic_dec_zero(_v) \
  99    (p_atomic_dec_return(_v) == 0)
 100
 101 #define p_atomic_inc(_v) \
 102    ((void) p_atomic_inc_return(_v))
 103
 104 #define p_atomic_inc_return(_v) (\
 105    sizeof *(_v) == sizeof(short)   ? _InterlockedIncrement16((short *)  (_v)) : \
 106    sizeof *(_v) == sizeof(long)    ? _InterlockedIncrement  ((long *)   (_v)) : \
 107    sizeof *(_v) == sizeof(__int64) ? InterlockedIncrement64 ((__int64 *)(_v)) : \
 108                                      (assert(!"should not get here"), 0))
 109
 110 #define p_atomic_dec(_v) \
 111    ((void) p_atomic_dec_return(_v))
 112
 113 #define p_atomic_dec_return(_v) (\
 114    sizeof *(_v) == sizeof(short)   ? _InterlockedDecrement16((short *)  (_v)) : \
 115    sizeof *(_v) == sizeof(long)    ? _InterlockedDecrement  ((long *)   (_v)) : \
 116    sizeof *(_v) == sizeof(__int64) ? InterlockedDecrement64 ((__int64 *)(_v)) : \
 117                                      (assert(!"should not get here"), 0))
 118
 119 #define p_atomic_cmpxchg(_v, _old, _new) (\
 120    sizeof *(_v) == sizeof(char)    ? _InterlockedCompareExchange8 ((char *)   (_v), (char)   (_new), (char)   (_old)) : \
 121    sizeof *(_v) == sizeof(short)   ? _InterlockedCompareExchange16((short *)  (_v), (short)  (_new), (short)  (_old)) : \
 122    sizeof *(_v) == sizeof(long)    ? _InterlockedCompareExchange  ((long *)   (_v), (long)   (_new), (long)   (_old)) : \
 123    sizeof *(_v) == sizeof(__int64) ? InterlockedCompareExchange64 ((__int64 *)(_v), (__int64)(_new), (__int64)(_old)) : \
 124                                      (assert(!"should not get here"), 0))
 125
 126 #endif
 127
 128 #if defined(PIPE_ATOMIC_OS_SOLARIS)
 129
 130 #define PIPE_ATOMIC "Solaris OS atomic functions"
 131
 132 #include <atomic.h>
 133 #include <assert.h>
 134
 135 #define p_atomic_set(_v, _i) (*(_v) = (_i))
 136 #define p_atomic_read(_v) (*(_v))
 137
 138 #define p_atomic_dec_zero(v) (\
 139    sizeof(*v) == sizeof(uint8_t)  ? atomic_dec_8_nv ((uint8_t  *)(v)) == 0 : \
 140    sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) == 0 : \
 141    sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) == 0 : \
 142    sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) == 0 : \
 143                                     (assert(!"should not get here"), 0))
 144
 145 #define p_atomic_inc(v) (void) (\
 146    sizeof(*v) == sizeof(uint8_t)  ? atomic_inc_8 ((uint8_t  *)(v)) : \
 147    sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16((uint16_t *)(v)) : \
 148    sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32((uint32_t *)(v)) : \
 149    sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64((uint64_t *)(v)) : \
 150                                     (assert(!"should not get here"), 0))
 151
 152 #define p_atomic_inc_return(v) ((typeof(*v)) \
 153    sizeof(*v) == sizeof(uint8_t)  ? atomic_inc_8_nv ((uint8_t  *)(v)) : \
 154    sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16_nv((uint16_t *)(v)) : \
 155    sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32_nv((uint32_t *)(v)) : \
 156    sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64_nv((uint64_t *)(v)) : \
 157                                     (assert(!"should not get here"), 0))
 158
 159 #define p_atomic_dec(v) ((void) \
 160    sizeof(*v) == sizeof(uint8_t)  ? atomic_dec_8 ((uint8_t  *)(v)) : \
 161    sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16((uint16_t *)(v)) : \
 162    sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32((uint32_t *)(v)) : \
 163    sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64((uint64_t *)(v)) : \
 164                                     (assert(!"should not get here"), 0))
 165
 166 #define p_atomic_dec_return(v) ((typeof(*v)) \
 167    sizeof(*v) == sizeof(uint8_t)  ? atomic_dec_8_nv ((uint8_t  *)(v)) : \
 168    sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) : \
 169    sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) : \
 170    sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) : \
 171                                     (assert(!"should not get here"), 0))
 172
 173 #define p_atomic_cmpxchg(v, old, _new) ((typeof(*v)) \
 174    sizeof(*v) == sizeof(uint8_t)  ? atomic_cas_8 ((uint8_t  *)(v), (uint8_t )(old), (uint8_t )(_new)) : \
 175    sizeof(*v) == sizeof(uint16_t) ? atomic_cas_16((uint16_t *)(v), (uint16_t)(old), (uint16_t)(_new)) : \
 176    sizeof(*v) == sizeof(uint32_t) ? atomic_cas_32((uint32_t *)(v), (uint32_t)(old), (uint32_t)(_new)) : \
 177    sizeof(*v) == sizeof(uint64_t) ? atomic_cas_64((uint64_t *)(v), (uint64_t)(old), (uint64_t)(_new)) : \
 178                                     (assert(!"should not get here"), 0))
 179
 180 #endif
 181
 182 #ifndef PIPE_ATOMIC
 183 #error "No pipe_atomic implementation selected"
 184 #endif
 185
 186
 187
 188 #endif /* U_ATOMIC_H */