1 /* 2 * Copyright (C) 2011 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 #ifndef BIONIC_ATOMIC_GCC_BUILTIN_H 17 #define BIONIC_ATOMIC_GCC_BUILTIN_H 18 19 /* This header file is used by default if we don't have optimized atomic 20 * routines for a given platform. See bionic_atomic_arm.h and 21 * bionic_atomic_x86.h for examples. 22 */ 23 24 __ATOMIC_INLINE__ void 25 __bionic_memory_barrier(void) 26 { 27 __sync_synchronize(); 28 } 29 30 __ATOMIC_INLINE__ int 31 __bionic_cmpxchg(int32_t old_value, int32_t new_value, volatile int32_t* ptr) 32 { 33 /* We must return 0 on success */ 34 return __sync_val_compare_and_swap(ptr, old_value, new_value) != old_value; 35 } 36 37 __ATOMIC_INLINE__ int32_t 38 __bionic_swap(int32_t new_value, volatile int32_t* ptr) 39 { 40 int32_t old_value; 41 do { 42 old_value = *ptr; 43 } while (__sync_val_compare_and_swap(ptr, old_value, new_value) != old_value); 44 return old_value; 45 } 46 47 __ATOMIC_INLINE__ int32_t 48 __bionic_atomic_inc(volatile int32_t* ptr) 49 { 50 /* We must return the old value */ 51 return __sync_fetch_and_add(ptr, 1); 52 } 53 54 __ATOMIC_INLINE__ int32_t 55 __bionic_atomic_dec(volatile int32_t* ptr) 56 { 57 /* We must return the old value */ 58 return __sync_fetch_and_add(ptr, -1); 59 } 60 61 #endif /* BIONIC_ATOMIC_GCC_BUILTIN_H */ 62
