1 | /** |
2 | * hdr_atomic.h |
3 | * Written by Philip Orwig and released to the public domain, |
4 | * as explained at http://creativecommons.org/publicdomain/zero/1.0/ |
5 | */ |
6 | |
7 | #ifndef HDR_ATOMIC_H__ |
8 | #define HDR_ATOMIC_H__ |
9 | |
10 | |
11 | #if defined(_MSC_VER) |
12 | |
13 | #include <stdint.h> |
14 | #include <intrin.h> |
15 | #include <stdbool.h> |
16 | |
17 | static void __inline * hdr_atomic_load_pointer(void** pointer) |
18 | { |
19 | _ReadBarrier(); |
20 | return *pointer; |
21 | } |
22 | |
23 | static void hdr_atomic_store_pointer(void** pointer, void* value) |
24 | { |
25 | _WriteBarrier(); |
26 | *pointer = value; |
27 | } |
28 | |
29 | static int64_t __inline hdr_atomic_load_64(int64_t* field) |
30 | { |
31 | _ReadBarrier(); |
32 | return *field; |
33 | } |
34 | |
35 | static void __inline hdr_atomic_store_64(int64_t* field, int64_t value) |
36 | { |
37 | _WriteBarrier(); |
38 | *field = value; |
39 | } |
40 | |
41 | static int64_t __inline hdr_atomic_exchange_64(volatile int64_t* field, int64_t value) |
42 | { |
43 | #if defined(_WIN64) |
44 | return _InterlockedExchange64(field, value); |
45 | #else |
46 | int64_t comparand; |
47 | int64_t initial_value = *field; |
48 | do |
49 | { |
50 | comparand = initial_value; |
51 | initial_value = _InterlockedCompareExchange64(field, value, comparand); |
52 | } |
53 | while (comparand != initial_value); |
54 | |
55 | return initial_value; |
56 | #endif |
57 | } |
58 | |
59 | static int64_t __inline hdr_atomic_add_fetch_64(volatile int64_t* field, int64_t value) |
60 | { |
61 | #if defined(_WIN64) |
62 | return _InterlockedExchangeAdd64(field, value) + value; |
63 | #else |
64 | int64_t comparand; |
65 | int64_t initial_value = *field; |
66 | do |
67 | { |
68 | comparand = initial_value; |
69 | initial_value = _InterlockedCompareExchange64(field, comparand + value, comparand); |
70 | } |
71 | while (comparand != initial_value); |
72 | |
73 | return initial_value + value; |
74 | #endif |
75 | } |
76 | |
77 | static bool __inline hdr_atomic_compare_exchange_64(volatile int64_t* field, int64_t* expected, int64_t desired) |
78 | { |
79 | return *expected == _InterlockedCompareExchange64(field, desired, *expected); |
80 | } |
81 | |
82 | #elif defined(__ATOMIC_SEQ_CST) |
83 | |
84 | #define hdr_atomic_load_pointer(x) __atomic_load_n(x, __ATOMIC_SEQ_CST) |
85 | #define hdr_atomic_store_pointer(f,v) __atomic_store_n(f,v, __ATOMIC_SEQ_CST) |
86 | #define hdr_atomic_load_64(x) __atomic_load_n(x, __ATOMIC_SEQ_CST) |
87 | #define hdr_atomic_store_64(f,v) __atomic_store_n(f,v, __ATOMIC_SEQ_CST) |
88 | #define hdr_atomic_exchange_64(f,i) __atomic_exchange_n(f,i, __ATOMIC_SEQ_CST) |
89 | #define hdr_atomic_add_fetch_64(field, value) __atomic_add_fetch(field, value, __ATOMIC_SEQ_CST) |
90 | #define hdr_atomic_compare_exchange_64(field, expected, desired) __atomic_compare_exchange_n(field, expected, desired, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) |
91 | |
92 | #elif defined(__x86_64__) |
93 | |
94 | #include <stdint.h> |
95 | #include <stdbool.h> |
96 | |
97 | static inline void* hdr_atomic_load_pointer(void** pointer) |
98 | { |
99 | void* p = *pointer; |
100 | asm volatile ("" ::: "memory" ); |
101 | return p; |
102 | } |
103 | |
104 | static inline void hdr_atomic_store_pointer(void** pointer, void* value) |
105 | { |
106 | asm volatile ("lock; xchgq %0, %1" : "+q" (value), "+m" (*pointer)); |
107 | } |
108 | |
109 | static inline int64_t hdr_atomic_load_64(int64_t* field) |
110 | { |
111 | int64_t i = *field; |
112 | asm volatile ("" ::: "memory" ); |
113 | return i; |
114 | } |
115 | |
116 | static inline void hdr_atomic_store_64(int64_t* field, int64_t value) |
117 | { |
118 | asm volatile ("lock; xchgq %0, %1" : "+q" (value), "+m" (*field)); |
119 | } |
120 | |
121 | static inline int64_t hdr_atomic_exchange_64(volatile int64_t* field, int64_t value) |
122 | { |
123 | int64_t result = 0; |
124 | asm volatile ("lock; xchgq %1, %2" : "=r" (result), "+q" (value), "+m" (*field)); |
125 | return result; |
126 | } |
127 | |
128 | static inline int64_t hdr_atomic_add_fetch_64(volatile int64_t* field, int64_t value) |
129 | { |
130 | return __sync_add_and_fetch(field, value); |
131 | } |
132 | |
133 | static inline bool hdr_atomic_compare_exchange_64(volatile int64_t* field, int64_t* expected, int64_t desired) |
134 | { |
135 | int64_t original; |
136 | asm volatile( "lock; cmpxchgq %2, %1" : "=a" (original), "+m" (*field) : "q" (desired), "0" (*expected)); |
137 | return original == *expected; |
138 | } |
139 | |
140 | #else |
141 | |
142 | #error "Unable to determine atomic operations for your platform" |
143 | |
144 | #endif |
145 | |
146 | #endif /* HDR_ATOMIC_H__ */ |
147 | |