1 /*
2 * Copyright (C) 2016 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 _ATOMIC_H_
18 #define _ATOMIC_H_
19
20 #ifdef __cplusplus
21 extern "C" {
22 #endif
23
24 #include <stdint.h>
25 #include <stdbool.h>
26 #include <cpu/inc/barrier.h>
27
28 /* almost all platforms support byte and 32-bit operations of this sort. please do not add other sizes here */
29 uint32_t atomicXchgByte(volatile uint8_t *byte, uint32_t newVal);
30 uint32_t atomicXchg32bits(volatile uint32_t *word, uint32_t newVal);
31 bool atomicCmpXchgByte(volatile uint8_t *byte, uint32_t prevVal, uint32_t newVal);
32 bool atomicCmpXchg32bits(volatile uint32_t *word, uint32_t prevVal, uint32_t newVal);
33
34 //returns old value
35 uint32_t atomicAddByte(volatile uint8_t *byte, uint32_t addend);
36 uint32_t atomicAdd32bits(volatile uint32_t *word, uint32_t addend);
37
38 //writes with barriers
atomicReadByte(volatile uint8_t * byte)39 static inline uint32_t atomicReadByte(volatile uint8_t *byte)
40 {
41 mem_reorder_barrier();
42 return *byte;
43 }
44
atomicRead32bits(volatile uint32_t * word)45 static inline uint32_t atomicRead32bits(volatile uint32_t *word)
46 {
47 mem_reorder_barrier();
48 return *word;
49 }
50
atomicWriteByte(volatile uint8_t * byte,uint32_t val)51 static inline void atomicWriteByte(volatile uint8_t *byte, uint32_t val)
52 {
53 *byte = val;
54 mem_reorder_barrier();
55 }
56
atomicWrite32bits(volatile uint32_t * word,uint32_t val)57 static inline void atomicWrite32bits(volatile uint32_t *word, uint32_t val)
58 {
59 *word = val;
60 mem_reorder_barrier();
61 }
62
63 #ifdef __cplusplus
64 }
65 #endif
66
67 #endif
68