Atomic.h revision 375fb116bcb817b37509ab579dbd55cdbb765cbf 
1/*
2 * Copyright (C) 2008 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
17/*
18 * Atomic operations
19 */
20#ifndef DALVIK_ATOMIC_H_
21#define DALVIK_ATOMIC_H_
22
23#include <cutils/atomic.h>          /* use common Android atomic ops */
24#include <cutils/atomic-inline.h>   /* and some uncommon ones */
25
26/*
27 * NOTE: Two "quasiatomic" operations on the exact same memory address
28 * are guaranteed to operate atomically with respect to each other,
29 * but no guarantees are made about quasiatomic operations mixed with
30 * non-quasiatomic operations on the same address, nor about
31 * quasiatomic operations that are performed on partially-overlapping
32 * memory.
33 *
34 * None of these provide a memory barrier.
35 */
36
37/*
38 * Swap the 64-bit value at "addr" with "value".  Returns the previous
39 * value.
40 */
41extern "C" int64_t dvmQuasiAtomicSwap64(int64_t value, volatile int64_t* addr);
42
43/*
44 * Read the 64-bit value at "addr".
45 */
46extern "C" int64_t dvmQuasiAtomicRead64(volatile const int64_t* addr);
47
48/*
49 * If the value at "addr" is equal to "oldvalue", replace it with "newvalue"
50 * and return 0.  Otherwise, don't swap, and return nonzero.
51 */
52int dvmQuasiAtomicCas64(int64_t oldvalue, int64_t newvalue,
53        volatile int64_t* addr);
54
55#endif  // DALVIK_ATOMIC_H_
56