1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * 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#ifndef BIONIC_ATOMIC_GCC_BUILTIN_H
17#define BIONIC_ATOMIC_GCC_BUILTIN_H
18
19/* This header file is used by default if we don't have optimized atomic
20 * routines for a given platform. See bionic_atomic_arm.h and
21 * bionic_atomic_x86.h for examples.
22 */
23
24__ATOMIC_INLINE__ void
25__bionic_memory_barrier(void)
26{
27    __sync_synchronize();
28}
29
30__ATOMIC_INLINE__ int
31__bionic_cmpxchg(int32_t old_value, int32_t new_value, volatile int32_t* ptr)
32{
33    /* We must return 0 on success */
34    return __sync_val_compare_and_swap(ptr, old_value, new_value) != old_value;
35}
36
37__ATOMIC_INLINE__ int32_t
38__bionic_swap(int32_t new_value, volatile int32_t* ptr)
39{
40    int32_t old_value;
41    do {
42        old_value = *ptr;
43    } while (__sync_val_compare_and_swap(ptr, old_value, new_value) != old_value);
44    return old_value;
45}
46
47__ATOMIC_INLINE__ int32_t
48__bionic_atomic_inc(volatile int32_t* ptr)
49{
50    /* We must return the old value */
51    return __sync_fetch_and_add(ptr, 1);
52}
53
54__ATOMIC_INLINE__ int32_t
55__bionic_atomic_dec(volatile int32_t* ptr)
56{
57    /* We must return the old value */
58    return __sync_fetch_and_add(ptr, -1);
59}
60
61#endif /* BIONIC_ATOMIC_GCC_BUILTIN_H */
62