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 #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 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  40 #define p_atomic_read(_v) (*(_v))
  41 #define p_atomic_dec_zero(v) (__sync_sub_and_fetch((v), 1) == 0)
  42 #define p_atomic_inc(v) (void) __sync_add_and_fetch((v), 1)
  43 #define p_atomic_dec(v) (void) __sync_sub_and_fetch((v), 1)
  44 #define p_atomic_add(v, i) (void) __sync_add_and_fetch((v), (i))
  45 #define p_atomic_inc_return(v) __sync_add_and_fetch((v), 1)
  46 #define p_atomic_dec_return(v) __sync_sub_and_fetch((v), 1)
  47 #define p_atomic_cmpxchg(v, old, _new) \
  48    __sync_val_compare_and_swap((v), (old), (_new))
  49
  50 #endif
  51
  52
  53
  54 /* Unlocked version for single threaded environments, such as some
  55  * windows kernel modules.
  56  */
  57 #if defined(PIPE_ATOMIC_OS_UNLOCKED)
  58
  59 #define PIPE_ATOMIC "Unlocked"
  60
  61 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  62 #define p_atomic_read(_v) (*(_v))
  63 #define p_atomic_dec_zero(_v) (p_atomic_dec_return(_v) == 0)
  64 #define p_atomic_inc(_v) ((void) p_atomic_inc_return(_v))
  65 #define p_atomic_dec(_v) ((void) p_atomic_dec_return(_v))
  66 #define p_atomic_add(_v, _i) (*(_v) = *(_v) + (_i))
  67 #define p_atomic_inc_return(_v) (++(*(_v)))
  68 #define p_atomic_dec_return(_v) (--(*(_v)))
  69 #define p_atomic_cmpxchg(_v, _old, _new) (*(_v) == (_old) ? (*(_v) = (_new), (_old)) : *(_v))
  70
  71 #endif
  72
  73
  74 #if defined(PIPE_ATOMIC_MSVC_INTRINSIC)
  75
  76 #define PIPE_ATOMIC "MSVC Intrinsics"
  77
  78 /* We use the Windows header's Interlocked*64 functions instead of the
  79  * _Interlocked*64 intrinsics wherever we can, as support for the latter varies
  80  * with target CPU, whereas Windows headers take care of all portability
  81  * issues: using intrinsics where available, falling back to library
  82  * implementations where not.
  83  */
  84 #ifndef WIN32_LEAN_AND_MEAN
  85 #define WIN32_LEAN_AND_MEAN 1
  86 #endif
  87 #include <windows.h>
  88 #include <intrin.h>
  89 #include <assert.h>
  90
  91 /* MSVC supports decltype keyword, but it's only supported on C++ and doesn't
  92  * quite work here; and if a C++-only solution is worthwhile, then it would be
  93  * better to use templates / function overloading, instead of decltype magic.
  94  * Therefore, we rely on implicit casting to LONGLONG for the functions that return
  95  */
  96
  97 #define p_atomic_set(_v, _i) (*(_v) = (_i))
  98 #define p_atomic_read(_v) (*(_v))
  99
 100 #define p_atomic_dec_zero(_v) \
 101    (p_atomic_dec_return(_v) == 0)
 102
 103 #define p_atomic_inc(_v) \
 104    ((void) p_atomic_inc_return(_v))
 105
 106 #define p_atomic_inc_return(_v) (\
 107    sizeof *(_v) == sizeof(short)   ? _InterlockedIncrement16((short *)  (_v)) : \
 108    sizeof *(_v) == sizeof(long)    ? _InterlockedIncrement  ((long *)   (_v)) : \
 109    sizeof *(_v) == sizeof(__int64) ? InterlockedIncrement64 ((__int64 *)(_v)) : \
 110                                      (assert(!"should not get here"), 0))
 111
 112 #define p_atomic_dec(_v) \
 113    ((void) p_atomic_dec_return(_v))
 114
 115 #define p_atomic_dec_return(_v) (\
 116    sizeof *(_v) == sizeof(short)   ? _InterlockedDecrement16((short *)  (_v)) : \
 117    sizeof *(_v) == sizeof(long)    ? _InterlockedDecrement  ((long *)   (_v)) : \
 118    sizeof *(_v) == sizeof(__int64) ? InterlockedDecrement64 ((__int64 *)(_v)) : \
 119                                      (assert(!"should not get here"), 0))
 120
 121 #define p_atomic_add(_v, _i) (\
 122    sizeof *(_v) == sizeof(char)    ? _InterlockedExchangeAdd8 ((char *)   (_v), (_i)) : \
 123    sizeof *(_v) == sizeof(short)   ? _InterlockedExchangeAdd16((short *)  (_v), (_i)) : \
 124    sizeof *(_v) == sizeof(long)    ? _InterlockedExchangeAdd  ((long *)   (_v), (_i)) : \
 125    sizeof *(_v) == sizeof(__int64) ? InterlockedExchangeAdd64((__int64 *)(_v), (_i)) : \
 126                                      (assert(!"should not get here"), 0))
 127
 128 #define p_atomic_cmpxchg(_v, _old, _new) (\
 129    sizeof *(_v) == sizeof(char)    ? _InterlockedCompareExchange8 ((char *)   (_v), (char)   (_new), (char)   (_old)) : \
 130    sizeof *(_v) == sizeof(short)   ? _InterlockedCompareExchange16((short *)  (_v), (short)  (_new), (short)  (_old)) : \
 131    sizeof *(_v) == sizeof(long)    ? _InterlockedCompareExchange  ((long *)   (_v), (long)   (_new), (long)   (_old)) : \
 132    sizeof *(_v) == sizeof(__int64) ? InterlockedCompareExchange64 ((__int64 *)(_v), (__int64)(_new), (__int64)(_old)) : \
 133                                      (assert(!"should not get here"), 0))
 134
 135 #endif
 136
 137 #if defined(PIPE_ATOMIC_OS_SOLARIS)
 138
 139 #define PIPE_ATOMIC "Solaris OS atomic functions"
 140
 141 #include <atomic.h>
 142 #include <assert.h>
 143
 144 #define p_atomic_set(_v, _i) (*(_v) = (_i))
 145 #define p_atomic_read(_v) (*(_v))
 146
 147 #define p_atomic_dec_zero(v) (\
 148    sizeof(*v) == sizeof(uint8_t)  ? atomic_dec_8_nv ((uint8_t  *)(v)) == 0 : \
 149    sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) == 0 : \
 150    sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) == 0 : \
 151    sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) == 0 : \
 152                                     (assert(!"should not get here"), 0))
 153
 154 #define p_atomic_inc(v) (void) (\
 155    sizeof(*v) == sizeof(uint8_t)  ? atomic_inc_8 ((uint8_t  *)(v)) : \
 156    sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16((uint16_t *)(v)) : \
 157    sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32((uint32_t *)(v)) : \
 158    sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64((uint64_t *)(v)) : \
 159                                     (assert(!"should not get here"), 0))
 160
 161 #define p_atomic_inc_return(v) ((__typeof(*v)) \
 162    sizeof(*v) == sizeof(uint8_t)  ? atomic_inc_8_nv ((uint8_t  *)(v)) : \
 163    sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16_nv((uint16_t *)(v)) : \
 164    sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32_nv((uint32_t *)(v)) : \
 165    sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64_nv((uint64_t *)(v)) : \
 166                                     (assert(!"should not get here"), 0))
 167
 168 #define p_atomic_dec(v) ((void) \
 169    sizeof(*v) == sizeof(uint8_t)  ? atomic_dec_8 ((uint8_t  *)(v)) : \
 170    sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16((uint16_t *)(v)) : \
 171    sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32((uint32_t *)(v)) : \
 172    sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64((uint64_t *)(v)) : \
 173                                     (assert(!"should not get here"), 0))
 174
 175 #define p_atomic_dec_return(v) ((__typeof(*v)) \
 176    sizeof(*v) == sizeof(uint8_t)  ? atomic_dec_8_nv ((uint8_t  *)(v)) : \
 177    sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) : \
 178    sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) : \
 179    sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) : \
 180                                     (assert(!"should not get here"), 0))
 181
 182 #define p_atomic_add(v, i) ((void)                                   \
 183    sizeof(*v) == sizeof(uint8_t)  ? atomic_add_8 ((uint8_t  *)(v), (i)) : \
 184    sizeof(*v) == sizeof(uint16_t) ? atomic_add_16((uint16_t *)(v), (i)) : \
 185    sizeof(*v) == sizeof(uint32_t) ? atomic_add_32((uint32_t *)(v), (i)) : \
 186    sizeof(*v) == sizeof(uint64_t) ? atomic_add_64((uint64_t *)(v), (i)) : \
 187                                     (assert(!"should not get here"), 0))
 188
 189 #define p_atomic_cmpxchg(v, old, _new) ((__typeof(*v)) \
 190    sizeof(*v) == sizeof(uint8_t)  ? atomic_cas_8 ((uint8_t  *)(v), (uint8_t )(old), (uint8_t )(_new)) : \
 191    sizeof(*v) == sizeof(uint16_t) ? atomic_cas_16((uint16_t *)(v), (uint16_t)(old), (uint16_t)(_new)) : \
 192    sizeof(*v) == sizeof(uint32_t) ? atomic_cas_32((uint32_t *)(v), (uint32_t)(old), (uint32_t)(_new)) : \
 193    sizeof(*v) == sizeof(uint64_t) ? atomic_cas_64((uint64_t *)(v), (uint64_t)(old), (uint64_t)(_new)) : \
 194                                     (assert(!"should not get here"), 0))
 195
 196 #endif
 197
 198 #ifndef PIPE_ATOMIC
 199 #error "No pipe_atomic implementation selected"
 200 #endif
 201
 202
 203
 204 #endif /* U_ATOMIC_H */