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