1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2012 Google Inc. All rights reserved. 3 // https://developers.google.com/protocol-buffers/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are 7 // met: 8 // 9 // * Redistributions of source code must retain the above copyright 10 // notice, this list of conditions and the following disclaimer. 11 // * Redistributions in binary form must reproduce the above 12 // copyright notice, this list of conditions and the following disclaimer 13 // in the documentation and/or other materials provided with the 14 // distribution. 15 // * Neither the name of Google Inc. nor the names of its 16 // contributors may be used to endorse or promote products derived from 17 // this software without specific prior written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 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 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 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 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 77 inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, 78 Atomic32 increment) { 79 return Barrier_AtomicIncrement(ptr, increment); 80 } 81 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 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 } 102 103 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 } 108 109 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) { 110 *ptr = value; 111 } 112 113 inline void MemoryBarrier() { 114 __sync_synchronize(); 115 } 116 117 inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { 118 *ptr = value; 119 MemoryBarrier(); 120 } 121 122 inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) { 123 MemoryBarrier(); 124 *ptr = value; 125 } 126 127 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { 128 return *ptr; 129 } 130 131 inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) { 132 Atomic32 value = *ptr; 133 MemoryBarrier(); 134 return value; 135 } 136 137 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
