1 // Protocol Buffers - Google's data interchange format
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30
31 // This file is an internal atomic implementation, use atomicops.h instead.
32
33 #ifndef GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM_QNX_H_
34 #define GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM_QNX_H_
35
36 // For _smp_cmpxchg()
37 #include <pthread.h>
38
39 namespace google {
40 namespace protobuf {
41 namespace internal {
42
QNXCmpxchg(Atomic32 old_value,Atomic32 new_value,volatile Atomic32 * ptr)43 inline Atomic32 QNXCmpxchg(Atomic32 old_value,
44 Atomic32 new_value,
45 volatile Atomic32* ptr) {
46 return static_cast<Atomic32>(
47 _smp_cmpxchg((volatile unsigned *)ptr,
48 (unsigned)old_value,
49 (unsigned)new_value));
50 }
51
52
NoBarrier_CompareAndSwap(volatile Atomic32 * ptr,Atomic32 old_value,Atomic32 new_value)53 inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
54 Atomic32 old_value,
55 Atomic32 new_value) {
56 Atomic32 prev_value = *ptr;
57 do {
58 if (!QNXCmpxchg(old_value, new_value,
59 const_cast<Atomic32*>(ptr))) {
60 return old_value;
61 }
62 prev_value = *ptr;
63 } while (prev_value == old_value);
64 return prev_value;
65 }
66
NoBarrier_AtomicExchange(volatile Atomic32 * ptr,Atomic32 new_value)67 inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
68 Atomic32 new_value) {
69 Atomic32 old_value;
70 do {
71 old_value = *ptr;
72 } while (QNXCmpxchg(old_value, new_value,
73 const_cast<Atomic32*>(ptr)));
74 return old_value;
75 }
76
NoBarrier_AtomicIncrement(volatile Atomic32 * ptr,Atomic32 increment)77 inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
78 Atomic32 increment) {
79 return Barrier_AtomicIncrement(ptr, increment);
80 }
81
Barrier_AtomicIncrement(volatile Atomic32 * ptr,Atomic32 increment)82 inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
83 Atomic32 increment) {
84 for (;;) {
85 // Atomic exchange the old value with an incremented one.
86 Atomic32 old_value = *ptr;
87 Atomic32 new_value = old_value + increment;
88 if (QNXCmpxchg(old_value, new_value,
89 const_cast<Atomic32*>(ptr)) == 0) {
90 // The exchange took place as expected.
91 return new_value;
92 }
93 // Otherwise, *ptr changed mid-loop and we need to retry.
94 }
95 }
96
Acquire_CompareAndSwap(volatile Atomic32 * ptr,Atomic32 old_value,Atomic32 new_value)97 inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
98 Atomic32 old_value,
99 Atomic32 new_value) {
100 return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
101 }
102
Release_CompareAndSwap(volatile Atomic32 * ptr,Atomic32 old_value,Atomic32 new_value)103 inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
104 Atomic32 old_value,
105 Atomic32 new_value) {
106 return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
107 }
108
NoBarrier_Store(volatile Atomic32 * ptr,Atomic32 value)109 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
110 *ptr = value;
111 }
112
MemoryBarrier()113 inline void MemoryBarrier() {
114 __sync_synchronize();
115 }
116
Acquire_Store(volatile Atomic32 * ptr,Atomic32 value)117 inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
118 *ptr = value;
119 MemoryBarrier();
120 }
121
Release_Store(volatile Atomic32 * ptr,Atomic32 value)122 inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
123 MemoryBarrier();
124 *ptr = value;
125 }
126
NoBarrier_Load(volatile const Atomic32 * ptr)127 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
128 return *ptr;
129 }
130
Acquire_Load(volatile const Atomic32 * ptr)131 inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
132 Atomic32 value = *ptr;
133 MemoryBarrier();
134 return value;
135 }
136
Release_Load(volatile const Atomic32 * ptr)137 inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
138 MemoryBarrier();
139 return *ptr;
140 }
141
142 } // namespace internal
143 } // namespace protobuf
144 } // namespace google
145
146 #endif // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM_QNX_H_
147