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| 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__ */ |
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