text: /* Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include "apr_arch_atomic.h"
  
  #ifdef USE_ATOMICS_IA32
  
  APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p)
  {
  #if defined (NEED_ATOMICS_GENERIC64)
      return apr__atomic_generic64_init(p);
  #else
      return APR_SUCCESS;
  #endif
  }
  
  APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem)
  {
      return *mem;
  }
  
  APR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val)
  {
      *mem = val;
  }
  
  APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val)
  {
      asm volatile ("lock; xaddl %0,%1"
                    : "=r" (val), "=m" (*mem)
                    : "0" (val), "m" (*mem)
                    : "memory", "cc");
      return val;
  }
  
  APR_DECLARE(void) apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val)
  {
      asm volatile ("lock; subl %1, %0"
                    : /* no output */
                    : "m" (*(mem)), "r" (val)
                    : "memory", "cc");
  }
  
  APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem)
  {
      return apr_atomic_add32(mem, 1);
  }
  
  APR_DECLARE(int) apr_atomic_dec32(volatile apr_uint32_t *mem)
  {
      unsigned char prev;
  
      asm volatile ("lock; decl %0; setnz %1"
                    : "=m" (*mem), "=qm" (prev)
                    : "m" (*mem)
                    : "memory");
  
      return prev;
  }
  
  APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t with,
                                             apr_uint32_t cmp)
  {
      apr_uint32_t prev;
  
      asm volatile ("lock; cmpxchgl %1, %2"
                    : "=a" (prev)
                    : "r" (with), "m" (*(mem)), "0"(cmp)
                    : "memory", "cc");
      return prev;
  }
  
  APR_DECLARE(apr_uint32_t) apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val)
  {
      apr_uint32_t prev = val;
  
      asm volatile ("xchgl %0, %1"
                    : "=r" (prev), "+m" (*mem)
                    : "0" (prev));
      return prev;
  }
  
  APR_DECLARE(void*) apr_atomic_casptr(volatile void **mem, void *with, const void *cmp)
  {
      void *prev;
  #if APR_SIZEOF_VOIDP == 4
      asm volatile ("lock; cmpxchgl %2, %1"
                    : "=a" (prev), "=m" (*mem)
                    : "r" (with), "m" (*mem), "0" (cmp));
  #elif APR_SIZEOF_VOIDP == 8
      asm volatile ("lock; cmpxchgq %q2, %1"
                    : "=a" (prev), "=m" (*mem)
                    : "r" ((unsigned long)with), "m" (*mem),
                      "0" ((unsigned long)cmp));
  #else
  #error APR_SIZEOF_VOIDP value not supported
  #endif
      return prev;
  }
  
  APR_DECLARE(void*) apr_atomic_xchgptr(volatile void **mem, void *with)
  {
      void *prev;
  #if APR_SIZEOF_VOIDP == 4
      asm volatile ("xchgl %2, %1"
                    : "=a" (prev), "+m" (*mem)
                    : "0" (with));
  #elif APR_SIZEOF_VOIDP == 8
      asm volatile ("xchgq %q2, %1"
                    : "=a" (prev), "+m" (*mem)
                    : "0" (with));
  #else
  #error APR_SIZEOF_VOIDP value not supported
  #endif
      return prev;
  }
  
  #endif /* USE_ATOMICS_IA32 */
  