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Member "apr-1.7.0/atomic/unix/ia32.c" (7 Mar 2019, 3778 Bytes) of package /linux/www/apr-1.7.0.tar.bz2:


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    1 /* Licensed to the Apache Software Foundation (ASF) under one or more
    2  * contributor license agreements.  See the NOTICE file distributed with
    3  * this work for additional information regarding copyright ownership.
    4  * The ASF licenses this file to You under the Apache License, Version 2.0
    5  * (the "License"); you may not use this file except in compliance with
    6  * the License.  You may obtain a copy of the License at
    7  *
    8  *     http://www.apache.org/licenses/LICENSE-2.0
    9  *
   10  * Unless required by applicable law or agreed to in writing, software
   11  * distributed under the License is distributed on an "AS IS" BASIS,
   12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   13  * See the License for the specific language governing permissions and
   14  * limitations under the License.
   15  */
   16 
   17 #include "apr_arch_atomic.h"
   18 
   19 #ifdef USE_ATOMICS_IA32
   20 
   21 APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p)
   22 {
   23 #if defined (NEED_ATOMICS_GENERIC64)
   24     return apr__atomic_generic64_init(p);
   25 #else
   26     return APR_SUCCESS;
   27 #endif
   28 }
   29 
   30 APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem)
   31 {
   32     return *mem;
   33 }
   34 
   35 APR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val)
   36 {
   37     *mem = val;
   38 }
   39 
   40 APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val)
   41 {
   42     asm volatile ("lock; xaddl %0,%1"
   43                   : "=r" (val), "=m" (*mem)
   44                   : "0" (val), "m" (*mem)
   45                   : "memory", "cc");
   46     return val;
   47 }
   48 
   49 APR_DECLARE(void) apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val)
   50 {
   51     asm volatile ("lock; subl %1, %0"
   52                   : /* no output */
   53                   : "m" (*(mem)), "r" (val)
   54                   : "memory", "cc");
   55 }
   56 
   57 APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem)
   58 {
   59     return apr_atomic_add32(mem, 1);
   60 }
   61 
   62 APR_DECLARE(int) apr_atomic_dec32(volatile apr_uint32_t *mem)
   63 {
   64     unsigned char prev;
   65 
   66     asm volatile ("lock; decl %0; setnz %1"
   67                   : "=m" (*mem), "=qm" (prev)
   68                   : "m" (*mem)
   69                   : "memory");
   70 
   71     return prev;
   72 }
   73 
   74 APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t with,
   75                                            apr_uint32_t cmp)
   76 {
   77     apr_uint32_t prev;
   78 
   79     asm volatile ("lock; cmpxchgl %1, %2"
   80                   : "=a" (prev)
   81                   : "r" (with), "m" (*(mem)), "0"(cmp)
   82                   : "memory", "cc");
   83     return prev;
   84 }
   85 
   86 APR_DECLARE(apr_uint32_t) apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val)
   87 {
   88     apr_uint32_t prev = val;
   89 
   90     asm volatile ("xchgl %0, %1"
   91                   : "=r" (prev), "+m" (*mem)
   92                   : "0" (prev));
   93     return prev;
   94 }
   95 
   96 APR_DECLARE(void*) apr_atomic_casptr(volatile void **mem, void *with, const void *cmp)
   97 {
   98     void *prev;
   99 #if APR_SIZEOF_VOIDP == 4
  100     asm volatile ("lock; cmpxchgl %2, %1"
  101                   : "=a" (prev), "=m" (*mem)
  102                   : "r" (with), "m" (*mem), "0" (cmp));
  103 #elif APR_SIZEOF_VOIDP == 8
  104     asm volatile ("lock; cmpxchgq %q2, %1"
  105                   : "=a" (prev), "=m" (*mem)
  106                   : "r" ((unsigned long)with), "m" (*mem),
  107                     "0" ((unsigned long)cmp));
  108 #else
  109 #error APR_SIZEOF_VOIDP value not supported
  110 #endif
  111     return prev;
  112 }
  113 
  114 APR_DECLARE(void*) apr_atomic_xchgptr(volatile void **mem, void *with)
  115 {
  116     void *prev;
  117 #if APR_SIZEOF_VOIDP == 4
  118     asm volatile ("xchgl %2, %1"
  119                   : "=a" (prev), "+m" (*mem)
  120                   : "0" (with));
  121 #elif APR_SIZEOF_VOIDP == 8
  122     asm volatile ("xchgq %q2, %1"
  123                   : "=a" (prev), "+m" (*mem)
  124                   : "0" (with));
  125 #else
  126 #error APR_SIZEOF_VOIDP value not supported
  127 #endif
  128     return prev;
  129 }
  130 
  131 #endif /* USE_ATOMICS_IA32 */