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
18 #include "apr.h"
19 #include "apr_atomic.h"
20
21 #include <stdlib.h>
22
apr_atomic_init(apr_pool_t * p)23 apr_status_t apr_atomic_init(apr_pool_t *p)
24 {
25 return APR_SUCCESS;
26 }
27
apr_atomic_add32(volatile apr_uint32_t * mem,apr_uint32_t val)28 apr_uint32_t apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val)
29 {
30 apr_uint32_t old, new_val;
31
32 old = *mem; /* old is automatically updated on cs failure */
33 do {
34 new_val = old + val;
35 } while (__cs(&old, (cs_t *)mem, new_val));
36 return old;
37 }
38
apr_atomic_sub32(volatile apr_uint32_t * mem,apr_uint32_t val)39 void apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val)
40 {
41 apr_uint32_t old, new_val;
42
43 old = *mem; /* old is automatically updated on cs failure */
44 do {
45 new_val = old - val;
46 } while (__cs(&old, (cs_t *)mem, new_val));
47 }
48
apr_atomic_inc32(volatile apr_uint32_t * mem)49 apr_uint32_t apr_atomic_inc32(volatile apr_uint32_t *mem)
50 {
51 return apr_atomic_add32(mem, 1);
52 }
53
apr_atomic_dec32(volatile apr_uint32_t * mem)54 int apr_atomic_dec32(volatile apr_uint32_t *mem)
55 {
56 apr_uint32_t old, new_val;
57
58 old = *mem; /* old is automatically updated on cs failure */
59 do {
60 new_val = old - 1;
61 } while (__cs(&old, (cs_t *)mem, new_val));
62
63 return new_val != 0;
64 }
65
apr_atomic_read32(volatile apr_uint32_t * mem)66 apr_uint32_t apr_atomic_read32(volatile apr_uint32_t *mem)
67 {
68 return *mem;
69 }
70
apr_atomic_set32(volatile apr_uint32_t * mem,apr_uint32_t val)71 void apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val)
72 {
73 *mem = val;
74 }
75
apr_atomic_cas32(volatile apr_uint32_t * mem,apr_uint32_t swap,apr_uint32_t cmp)76 apr_uint32_t apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t swap,
77 apr_uint32_t cmp)
78 {
79 apr_uint32_t old = cmp;
80
81 __cs(&old, (cs_t *)mem, swap);
82 return old; /* old is automatically updated from mem on cs failure */
83 }
84
85 #if APR_SIZEOF_VOIDP == 4
apr_atomic_casptr(volatile void ** mem_ptr,void * swap_ptr,const void * cmp_ptr)86 void *apr_atomic_casptr(volatile void **mem_ptr,
87 void *swap_ptr,
88 const void *cmp_ptr)
89 {
90 __cs1(&cmp_ptr, /* automatically updated from mem on __cs1 failure */
91 mem_ptr, /* set from swap when __cs1 succeeds */
92 &swap_ptr);
93 return (void *)cmp_ptr;
94 }
95 #elif APR_SIZEOF_VOIDP == 8
apr_atomic_casptr(volatile void ** mem_ptr,void * swap_ptr,const void * cmp_ptr)96 void *apr_atomic_casptr(volatile void **mem_ptr,
97 void *swap_ptr,
98 const void *cmp_ptr)
99 {
100 __csg(&cmp_ptr, /* automatically updated from mem on __csg failure */
101 mem_ptr, /* set from swap when __csg succeeds */
102 &swap_ptr);
103 return (void *)cmp_ptr;
104 }
105 #else
106 #error APR_SIZEOF_VOIDP value not supported
107 #endif /* APR_SIZEOF_VOIDP */
108
apr_atomic_xchg32(volatile apr_uint32_t * mem,apr_uint32_t val)109 apr_uint32_t apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val)
110 {
111 apr_uint32_t old, new_val;
112
113 old = *mem; /* old is automatically updated on cs failure */
114 do {
115 new_val = val;
116 } while (__cs(&old, (cs_t *)mem, new_val));
117
118 return old;
119 }
120
apr_atomic_xchgptr(volatile void ** mem_ptr,void * new_ptr)121 APR_DECLARE(void*) apr_atomic_xchgptr(volatile void **mem_ptr, void *new_ptr)
122 {
123 void *old_ptr;
124
125 old_ptr = *(void **)mem_ptr; /* old is automatically updated on cs failure */
126 #if APR_SIZEOF_VOIDP == 4
127 do {
128 } while (__cs1(&old_ptr, mem_ptr, &new_ptr));
129 #elif APR_SIZEOF_VOIDP == 8
130 do {
131 } while (__csg(&old_ptr, mem_ptr, &new_ptr));
132 #else
133 #error APR_SIZEOF_VOIDP value not supported
134 #endif /* APR_SIZEOF_VOIDP */
135
136 return old_ptr;
137 }
138