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
21APR_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
30APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem)
31{
32    return *mem;
33}
34
35APR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val)
36{
37    *mem = val;
38}
39
40APR_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
49APR_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
57APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem)
58{
59    return apr_atomic_add32(mem, 1);
60}
61
62APR_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
74APR_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
86APR_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
96APR_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
114APR_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 */
132