80 lines
2.4 KiB
C
80 lines
2.4 KiB
C
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_CUTILS_ATOMIC_H
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#define ANDROID_CUTILS_ATOMIC_H
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#include <stdint.h>
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#include <sys/types.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* NOTE: memory shared between threads is synchronized by all atomic operations
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* below, this means that no explicit memory barrier is required: all reads or
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* writes issued before android_atomic_* operations are guaranteed to complete
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* before the atomic operation takes place.
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*/
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void android_atomic_write(int32_t value, volatile int32_t* addr);
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/*
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* all these atomic operations return the previous value
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*/
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int32_t android_atomic_inc(volatile int32_t* addr);
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int32_t android_atomic_dec(volatile int32_t* addr);
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int32_t android_atomic_add(int32_t value, volatile int32_t* addr);
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int32_t android_atomic_and(int32_t value, volatile int32_t* addr);
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int32_t android_atomic_or(int32_t value, volatile int32_t* addr);
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int32_t android_atomic_swap(int32_t value, volatile int32_t* addr);
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/*
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* NOTE: Two "quasiatomic" operations on the exact same memory address
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* are guaranteed to operate atomically with respect to each other,
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* but no guarantees are made about quasiatomic operations mixed with
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* non-quasiatomic operations on the same address, nor about
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* quasiatomic operations that are performed on partially-overlapping
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* memory.
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*/
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int64_t android_quasiatomic_swap_64(int64_t value, volatile int64_t* addr);
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int64_t android_quasiatomic_read_64(volatile int64_t* addr);
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/*
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* cmpxchg return a non zero value if the exchange was NOT performed,
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* in other words if oldvalue != *addr
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*/
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int android_atomic_cmpxchg(int32_t oldvalue, int32_t newvalue,
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volatile int32_t* addr);
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int android_quasiatomic_cmpxchg_64(int64_t oldvalue, int64_t newvalue,
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volatile int64_t* addr);
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // ANDROID_CUTILS_ATOMIC_H
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