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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