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Diffstat (limited to 'media/omx-plugin/include/ics/cutils/atomic.h')
-rw-r--r-- | media/omx-plugin/include/ics/cutils/atomic.h | 121 |
1 files changed, 0 insertions, 121 deletions
diff --git a/media/omx-plugin/include/ics/cutils/atomic.h b/media/omx-plugin/include/ics/cutils/atomic.h deleted file mode 100644 index ae42eb8a0..000000000 --- a/media/omx-plugin/include/ics/cutils/atomic.h +++ /dev/null @@ -1,121 +0,0 @@ -/* - * Copyright (C) 2007 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#ifndef ANDROID_CUTILS_ATOMIC_H -#define ANDROID_CUTILS_ATOMIC_H - -#include <stdint.h> -#include <sys/types.h> - -#ifdef __cplusplus -extern "C" { -#endif - -/* - * A handful of basic atomic operations. The appropriate pthread - * functions should be used instead of these whenever possible. - * - * The "acquire" and "release" terms can be defined intuitively in terms - * of the placement of memory barriers in a simple lock implementation: - * - wait until compare-and-swap(lock-is-free --> lock-is-held) succeeds - * - barrier - * - [do work] - * - barrier - * - store(lock-is-free) - * In very crude terms, the initial (acquire) barrier prevents any of the - * "work" from happening before the lock is held, and the later (release) - * barrier ensures that all of the work happens before the lock is released. - * (Think of cached writes, cache read-ahead, and instruction reordering - * around the CAS and store instructions.) - * - * The barriers must apply to both the compiler and the CPU. Note it is - * legal for instructions that occur before an "acquire" barrier to be - * moved down below it, and for instructions that occur after a "release" - * barrier to be moved up above it. - * - * The ARM-driven implementation we use here is short on subtlety, - * and actually requests a full barrier from the compiler and the CPU. - * The only difference between acquire and release is in whether they - * are issued before or after the atomic operation with which they - * are associated. To ease the transition to C/C++ atomic intrinsics, - * you should not rely on this, and instead assume that only the minimal - * acquire/release protection is provided. - * - * NOTE: all int32_t* values are expected to be aligned on 32-bit boundaries. - * If they are not, atomicity is not guaranteed. - */ - -/* - * Basic arithmetic and bitwise operations. These all provide a - * barrier with "release" ordering, and return the previous value. - * - * These have the same characteristics (e.g. what happens on overflow) - * as the equivalent non-atomic C operations. - */ -int32_t android_atomic_inc(volatile int32_t* addr); -int32_t android_atomic_dec(volatile int32_t* addr); -int32_t android_atomic_add(int32_t value, volatile int32_t* addr); -int32_t android_atomic_and(int32_t value, volatile int32_t* addr); -int32_t android_atomic_or(int32_t value, volatile int32_t* addr); - -/* - * Perform an atomic load with "acquire" or "release" ordering. - * - * This is only necessary if you need the memory barrier. A 32-bit read - * from a 32-bit aligned address is atomic on all supported platforms. - */ -int32_t android_atomic_acquire_load(volatile const int32_t* addr); -int32_t android_atomic_release_load(volatile const int32_t* addr); - -/* - * Perform an atomic store with "acquire" or "release" ordering. - * - * This is only necessary if you need the memory barrier. A 32-bit write - * to a 32-bit aligned address is atomic on all supported platforms. - */ -void android_atomic_acquire_store(int32_t value, volatile int32_t* addr); -void android_atomic_release_store(int32_t value, volatile int32_t* addr); - -/* - * Compare-and-set operation with "acquire" or "release" ordering. - * - * This returns zero if the new value was successfully stored, which will - * only happen when *addr == oldvalue. - * - * (The return value is inverted from implementations on other platforms, - * but matches the ARM ldrex/strex result.) - * - * Implementations that use the release CAS in a loop may be less efficient - * than possible, because we re-issue the memory barrier on each iteration. - */ -int android_atomic_acquire_cas(int32_t oldvalue, int32_t newvalue, - volatile int32_t* addr); -int android_atomic_release_cas(int32_t oldvalue, int32_t newvalue, - volatile int32_t* addr); - -/* - * Aliases for code using an older version of this header. These are now - * deprecated and should not be used. The definitions will be removed - * in a future release. - */ -#define android_atomic_write android_atomic_release_store -#define android_atomic_cmpxchg android_atomic_release_cas - -#ifdef __cplusplus -} // extern "C" -#endif - -#endif // ANDROID_CUTILS_ATOMIC_H |