src/util/u_atomic.c

   1 /*
   2  * Copyright © 2017 Gražvydas Ignotas
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #if defined(MISSING_64BIT_ATOMICS) && defined(HAVE_PTHREAD)
  25
  26 #include <stdint.h>
  27 #include <pthread.h>
  28
  29 #if defined(HAVE_FUNC_ATTRIBUTE_WEAK) && !defined(__CYGWIN__)
  30 #define WEAK __attribute__((weak))
  31 #else
  32 #define WEAK
  33 #endif
  34
  35 static pthread_mutex_t sync_mutex = PTHREAD_MUTEX_INITIALIZER;
  36
  37 WEAK uint64_t
  38 __sync_add_and_fetch_8(uint64_t *ptr, uint64_t val)
  39 {
  40    uint64_t r;
  41
  42    pthread_mutex_lock(&sync_mutex);
  43    *ptr += val;
  44    r = *ptr;
  45    pthread_mutex_unlock(&sync_mutex);
  46
  47    return r;
  48 }
  49
  50 WEAK uint64_t
  51 __sync_sub_and_fetch_8(uint64_t *ptr, uint64_t val)
  52 {
  53    uint64_t r;
  54
  55    pthread_mutex_lock(&sync_mutex);
  56    *ptr -= val;
  57    r = *ptr;
  58    pthread_mutex_unlock(&sync_mutex);
  59
  60    return r;
  61 }
  62
  63 WEAK uint64_t
  64 __sync_val_compare_and_swap_8(uint64_t *ptr, uint64_t oldval, uint64_t newval)
  65 {
  66    uint64_t r;
  67
  68    pthread_mutex_lock(&sync_mutex);
  69    r = *ptr;
  70    if (*ptr == oldval)
  71       *ptr = newval;
  72    pthread_mutex_unlock(&sync_mutex);
  73
  74    return r;
  75 }
  76
  77 #endif