1 /*
2 * Copyright (C) 2010 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 ANDROID_CUTILS_ATOMIC_X86_H
18 #define ANDROID_CUTILS_ATOMIC_X86_H
19
20 #include <stdint.h>
21
android_compiler_barrier(void)22 extern inline void android_compiler_barrier(void)
23 {
24 __asm__ __volatile__ ("" : : : "memory");
25 }
26
27 #if ANDROID_SMP == 0
android_memory_barrier(void)28 extern inline void android_memory_barrier(void)
29 {
30 android_compiler_barrier();
31 }
32 #else
android_memory_barrier(void)33 extern inline void android_memory_barrier(void)
34 {
35 __asm__ __volatile__ ("mfence" : : : "memory");
36 }
37 #endif
38
android_atomic_acquire_load(volatile const int32_t * ptr)39 extern inline int32_t android_atomic_acquire_load(volatile const int32_t *ptr)
40 {
41 int32_t value = *ptr;
42 android_compiler_barrier();
43 return value;
44 }
45
android_atomic_release_load(volatile const int32_t * ptr)46 extern inline int32_t android_atomic_release_load(volatile const int32_t *ptr)
47 {
48 android_memory_barrier();
49 return *ptr;
50 }
51
android_atomic_acquire_store(int32_t value,volatile int32_t * ptr)52 extern inline void android_atomic_acquire_store(int32_t value,
53 volatile int32_t *ptr)
54 {
55 *ptr = value;
56 android_memory_barrier();
57 }
58
android_atomic_release_store(int32_t value,volatile int32_t * ptr)59 extern inline void android_atomic_release_store(int32_t value,
60 volatile int32_t *ptr)
61 {
62 android_compiler_barrier();
63 *ptr = value;
64 }
65
android_atomic_cas(int32_t old_value,int32_t new_value,volatile int32_t * ptr)66 extern inline int android_atomic_cas(int32_t old_value, int32_t new_value,
67 volatile int32_t *ptr)
68 {
69 int32_t prev;
70 __asm__ __volatile__ ("lock; cmpxchgl %1, %2"
71 : "=a" (prev)
72 : "q" (new_value), "m" (*ptr), "0" (old_value)
73 : "memory");
74 return prev != old_value;
75 }
76
android_atomic_acquire_cas(int32_t old_value,int32_t new_value,volatile int32_t * ptr)77 extern inline int android_atomic_acquire_cas(int32_t old_value,
78 int32_t new_value,
79 volatile int32_t *ptr)
80 {
81 /* Loads are not reordered with other loads. */
82 return android_atomic_cas(old_value, new_value, ptr);
83 }
84
android_atomic_release_cas(int32_t old_value,int32_t new_value,volatile int32_t * ptr)85 extern inline int android_atomic_release_cas(int32_t old_value,
86 int32_t new_value,
87 volatile int32_t *ptr)
88 {
89 /* Stores are not reordered with other stores. */
90 return android_atomic_cas(old_value, new_value, ptr);
91 }
92
android_atomic_swap(int32_t new_value,volatile int32_t * ptr)93 extern inline int32_t android_atomic_swap(int32_t new_value,
94 volatile int32_t *ptr)
95 {
96 __asm__ __volatile__ ("xchgl %1, %0"
97 : "=r" (new_value)
98 : "m" (*ptr), "0" (new_value)
99 : "memory");
100 /* new_value now holds the old value of *ptr */
101 return new_value;
102 }
103
android_atomic_add(int32_t increment,volatile int32_t * ptr)104 extern inline int32_t android_atomic_add(int32_t increment,
105 volatile int32_t *ptr)
106 {
107 __asm__ __volatile__ ("lock; xaddl %0, %1"
108 : "+r" (increment), "+m" (*ptr)
109 : : "memory");
110 /* increment now holds the old value of *ptr */
111 return increment;
112 }
113
android_atomic_inc(volatile int32_t * addr)114 extern inline int32_t android_atomic_inc(volatile int32_t *addr)
115 {
116 return android_atomic_add(1, addr);
117 }
118
android_atomic_dec(volatile int32_t * addr)119 extern inline int32_t android_atomic_dec(volatile int32_t *addr)
120 {
121 return android_atomic_add(-1, addr);
122 }
123
android_atomic_and(int32_t value,volatile int32_t * ptr)124 extern inline int32_t android_atomic_and(int32_t value,
125 volatile int32_t *ptr)
126 {
127 int32_t prev, status;
128 do {
129 prev = *ptr;
130 status = android_atomic_cas(prev, prev & value, ptr);
131 } while (__builtin_expect(status != 0, 0));
132 return prev;
133 }
134
android_atomic_or(int32_t value,volatile int32_t * ptr)135 extern inline int32_t android_atomic_or(int32_t value, volatile int32_t *ptr)
136 {
137 int32_t prev, status;
138 do {
139 prev = *ptr;
140 status = android_atomic_cas(prev, prev | value, ptr);
141 } while (__builtin_expect(status != 0, 0));
142 return prev;
143 }
144
145 #endif /* ANDROID_CUTILS_ATOMIC_X86_H */
146