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/*
* Copyright (C) 2010 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_ARM_H
#define ANDROID_CUTILS_ATOMIC_ARM_H
#include <stdint.h>
#ifndef ANDROID_ATOMIC_INLINE
#define ANDROID_ATOMIC_INLINE inline __attribute__((always_inline))
#endif
extern ANDROID_ATOMIC_INLINE void android_compiler_barrier()
{
__asm__ __volatile__ ("" : : : "memory");
}
extern ANDROID_ATOMIC_INLINE void android_memory_barrier()
{
#if ANDROID_SMP == 0
android_compiler_barrier();
#else
__asm__ __volatile__ ("dmb" : : : "memory");
#endif
}
extern ANDROID_ATOMIC_INLINE
int32_t android_atomic_acquire_load(volatile const int32_t *ptr)
{
int32_t value = *ptr;
android_memory_barrier();
return value;
}
extern ANDROID_ATOMIC_INLINE
int32_t android_atomic_release_load(volatile const int32_t *ptr)
{
android_memory_barrier();
return *ptr;
}
extern ANDROID_ATOMIC_INLINE
void android_atomic_acquire_store(int32_t value, volatile int32_t *ptr)
{
*ptr = value;
android_memory_barrier();
}
extern ANDROID_ATOMIC_INLINE
void android_atomic_release_store(int32_t value, volatile int32_t *ptr)
{
android_memory_barrier();
*ptr = value;
}
extern ANDROID_ATOMIC_INLINE
int android_atomic_cas(int32_t old_value, int32_t new_value,
volatile int32_t *ptr)
{
int32_t prev, status;
do {
__asm__ __volatile__ ("ldrex %0, [%3]\n"
"mov %1, #0\n"
"teq %0, %4\n"
#ifdef __thumb2__
"it eq\n"
#endif
"strexeq %1, %5, [%3]"
: "=&r" (prev), "=&r" (status), "+m"(*ptr)
: "r" (ptr), "Ir" (old_value), "r" (new_value)
: "cc");
} while (__builtin_expect(status != 0, 0));
return prev != old_value;
}
extern ANDROID_ATOMIC_INLINE
int android_atomic_acquire_cas(int32_t old_value, int32_t new_value,
volatile int32_t *ptr)
{
int status = android_atomic_cas(old_value, new_value, ptr);
android_memory_barrier();
return status;
}
extern ANDROID_ATOMIC_INLINE
int android_atomic_release_cas(int32_t old_value, int32_t new_value,
volatile int32_t *ptr)
{
android_memory_barrier();
return android_atomic_cas(old_value, new_value, ptr);
}
extern ANDROID_ATOMIC_INLINE
int32_t android_atomic_add(int32_t increment, volatile int32_t *ptr)
{
int32_t prev, tmp, status;
android_memory_barrier();
do {
__asm__ __volatile__ ("ldrex %0, [%4]\n"
"add %1, %0, %5\n"
"strex %2, %1, [%4]"
: "=&r" (prev), "=&r" (tmp),
"=&r" (status), "+m" (*ptr)
: "r" (ptr), "Ir" (increment)
: "cc");
} while (__builtin_expect(status != 0, 0));
return prev;
}
extern ANDROID_ATOMIC_INLINE int32_t android_atomic_inc(volatile int32_t *addr)
{
return android_atomic_add(1, addr);
}
extern ANDROID_ATOMIC_INLINE int32_t android_atomic_dec(volatile int32_t *addr)
{
return android_atomic_add(-1, addr);
}
extern ANDROID_ATOMIC_INLINE
int32_t android_atomic_and(int32_t value, volatile int32_t *ptr)
{
int32_t prev, tmp, status;
android_memory_barrier();
do {
__asm__ __volatile__ ("ldrex %0, [%4]\n"
"and %1, %0, %5\n"
"strex %2, %1, [%4]"
: "=&r" (prev), "=&r" (tmp),
"=&r" (status), "+m" (*ptr)
: "r" (ptr), "Ir" (value)
: "cc");
} while (__builtin_expect(status != 0, 0));
return prev;
}
extern ANDROID_ATOMIC_INLINE
int32_t android_atomic_or(int32_t value, volatile int32_t *ptr)
{
int32_t prev, tmp, status;
android_memory_barrier();
do {
__asm__ __volatile__ ("ldrex %0, [%4]\n"
"orr %1, %0, %5\n"
"strex %2, %1, [%4]"
: "=&r" (prev), "=&r" (tmp),
"=&r" (status), "+m" (*ptr)
: "r" (ptr), "Ir" (value)
: "cc");
} while (__builtin_expect(status != 0, 0));
return prev;
}
#endif /* ANDROID_CUTILS_ATOMIC_ARM_H */
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