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 }
android_memory_store_barrier(void)36 extern ANDROID_ATOMIC_INLINE void android_memory_store_barrier(void)
37 {
38 android_compiler_barrier();
39 }
40 #else
android_memory_barrier(void)41 extern ANDROID_ATOMIC_INLINE void android_memory_barrier(void)
42 {
43 __asm__ __volatile__ ("mfence" : : : "memory");
44 }
android_memory_store_barrier(void)45 extern ANDROID_ATOMIC_INLINE void android_memory_store_barrier(void)
46 {
47 android_compiler_barrier();
48 }
49 #endif
50
51 extern ANDROID_ATOMIC_INLINE int32_t
android_atomic_acquire_load(volatile const int32_t * ptr)52 android_atomic_acquire_load(volatile const int32_t *ptr)
53 {
54 int32_t value = *ptr;
55 android_compiler_barrier();
56 return value;
57 }
58
59 extern ANDROID_ATOMIC_INLINE int32_t
android_atomic_release_load(volatile const int32_t * ptr)60 android_atomic_release_load(volatile const int32_t *ptr)
61 {
62 android_memory_barrier();
63 return *ptr;
64 }
65
66 extern ANDROID_ATOMIC_INLINE void
android_atomic_acquire_store(int32_t value,volatile int32_t * ptr)67 android_atomic_acquire_store(int32_t value, volatile int32_t *ptr)
68 {
69 *ptr = value;
70 android_memory_barrier();
71 }
72
73 extern ANDROID_ATOMIC_INLINE void
android_atomic_release_store(int32_t value,volatile int32_t * ptr)74 android_atomic_release_store(int32_t value, volatile int32_t *ptr)
75 {
76 android_compiler_barrier();
77 *ptr = value;
78 }
79
80 extern ANDROID_ATOMIC_INLINE int
android_atomic_cas(int32_t old_value,int32_t new_value,volatile int32_t * ptr)81 android_atomic_cas(int32_t old_value, int32_t new_value, volatile int32_t *ptr)
82 {
83 int32_t prev;
84 __asm__ __volatile__ ("lock; cmpxchgl %1, %2"
85 : "=a" (prev)
86 : "q" (new_value), "m" (*ptr), "0" (old_value)
87 : "memory");
88 return prev != old_value;
89 }
90
91 extern ANDROID_ATOMIC_INLINE int
android_atomic_acquire_cas(int32_t old_value,int32_t new_value,volatile int32_t * ptr)92 android_atomic_acquire_cas(int32_t old_value,
93 int32_t new_value,
94 volatile int32_t *ptr)
95 {
96 /* Loads are not reordered with other loads. */
97 return android_atomic_cas(old_value, new_value, ptr);
98 }
99
100 extern ANDROID_ATOMIC_INLINE int
android_atomic_release_cas(int32_t old_value,int32_t new_value,volatile int32_t * ptr)101 android_atomic_release_cas(int32_t old_value,
102 int32_t new_value,
103 volatile int32_t *ptr)
104 {
105 /* Stores are not reordered with other stores. */
106 return android_atomic_cas(old_value, new_value, ptr);
107 }
108
109 extern ANDROID_ATOMIC_INLINE int32_t
android_atomic_add(int32_t increment,volatile int32_t * ptr)110 android_atomic_add(int32_t increment, volatile int32_t *ptr)
111 {
112 __asm__ __volatile__ ("lock; xaddl %0, %1"
113 : "+r" (increment), "+m" (*ptr)
114 : : "memory");
115 /* increment now holds the old value of *ptr */
116 return increment;
117 }
118
119 extern ANDROID_ATOMIC_INLINE int32_t
android_atomic_inc(volatile int32_t * addr)120 android_atomic_inc(volatile int32_t *addr)
121 {
122 return android_atomic_add(1, addr);
123 }
124
125 extern ANDROID_ATOMIC_INLINE int32_t
android_atomic_dec(volatile int32_t * addr)126 android_atomic_dec(volatile int32_t *addr)
127 {
128 return android_atomic_add(-1, addr);
129 }
130
131 extern ANDROID_ATOMIC_INLINE int32_t
android_atomic_and(int32_t value,volatile int32_t * ptr)132 android_atomic_and(int32_t value, volatile int32_t *ptr)
133 {
134 int32_t prev, status;
135 do {
136 prev = *ptr;
137 status = android_atomic_cas(prev, prev & value, ptr);
138 } while (__builtin_expect(status != 0, 0));
139 return prev;
140 }
141
142 extern ANDROID_ATOMIC_INLINE int32_t
android_atomic_or(int32_t value,volatile int32_t * ptr)143 android_atomic_or(int32_t value, volatile int32_t *ptr)
144 {
145 int32_t prev, status;
146 do {
147 prev = *ptr;
148 status = android_atomic_cas(prev, prev | value, ptr);
149 } while (__builtin_expect(status != 0, 0));
150 return prev;
151 }
152
153 #endif /* ANDROID_CUTILS_ATOMIC_X86_H */
154