The Android Open Source Project | dd7bc33 | 2009-03-03 19:32:55 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2007 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 | #ifndef ANDROID_CUTILS_ATOMIC_H |
| 18 | #define ANDROID_CUTILS_ATOMIC_H |
| 19 | |
| 20 | #include <stdint.h> |
| 21 | #include <sys/types.h> |
| 22 | |
| 23 | #ifdef __cplusplus |
| 24 | extern "C" { |
| 25 | #endif |
| 26 | |
| 27 | /* |
| 28 | * NOTE: memory shared between threads is synchronized by all atomic operations |
| 29 | * below, this means that no explicit memory barrier is required: all reads or |
| 30 | * writes issued before android_atomic_* operations are guaranteed to complete |
| 31 | * before the atomic operation takes place. |
| 32 | */ |
| 33 | |
| 34 | void android_atomic_write(int32_t value, volatile int32_t* addr); |
| 35 | |
| 36 | /* |
| 37 | * all these atomic operations return the previous value |
| 38 | */ |
| 39 | |
| 40 | |
| 41 | int32_t android_atomic_inc(volatile int32_t* addr); |
| 42 | int32_t android_atomic_dec(volatile int32_t* addr); |
| 43 | |
| 44 | int32_t android_atomic_add(int32_t value, volatile int32_t* addr); |
| 45 | int32_t android_atomic_and(int32_t value, volatile int32_t* addr); |
| 46 | int32_t android_atomic_or(int32_t value, volatile int32_t* addr); |
| 47 | |
| 48 | int32_t android_atomic_swap(int32_t value, volatile int32_t* addr); |
| 49 | |
| 50 | /* |
| 51 | * NOTE: Two "quasiatomic" operations on the exact same memory address |
| 52 | * are guaranteed to operate atomically with respect to each other, |
| 53 | * but no guarantees are made about quasiatomic operations mixed with |
| 54 | * non-quasiatomic operations on the same address, nor about |
| 55 | * quasiatomic operations that are performed on partially-overlapping |
| 56 | * memory. |
| 57 | */ |
| 58 | |
| 59 | int64_t android_quasiatomic_swap_64(int64_t value, volatile int64_t* addr); |
| 60 | int64_t android_quasiatomic_read_64(volatile int64_t* addr); |
| 61 | |
| 62 | /* |
| 63 | * cmpxchg return a non zero value if the exchange was NOT performed, |
| 64 | * in other words if oldvalue != *addr |
| 65 | */ |
| 66 | |
| 67 | int android_atomic_cmpxchg(int32_t oldvalue, int32_t newvalue, |
| 68 | volatile int32_t* addr); |
| 69 | |
| 70 | int android_quasiatomic_cmpxchg_64(int64_t oldvalue, int64_t newvalue, |
| 71 | volatile int64_t* addr); |
| 72 | |
| 73 | |
| 74 | |
| 75 | #ifdef __cplusplus |
| 76 | } // extern "C" |
| 77 | #endif |
| 78 | |
| 79 | #endif // ANDROID_CUTILS_ATOMIC_H |