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| 1 // Copyright 2010 the V8 project authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 // This file is an internal atomic implementation, use atomicops.h instead. | |
| 6 | |
| 7 #ifndef V8_ATOMICOPS_INTERNALS_MIPS_GCC_H_ | |
| 8 #define V8_ATOMICOPS_INTERNALS_MIPS_GCC_H_ | |
| 9 | |
| 10 namespace v8 { | |
| 11 namespace internal { | |
| 12 | |
| 13 // Atomically execute: | |
| 14 // result = *ptr; | |
| 15 // if (*ptr == old_value) | |
| 16 // *ptr = new_value; | |
| 17 // return result; | |
| 18 // | |
| 19 // I.e., replace "*ptr" with "new_value" if "*ptr" used to be "old_value". | |
| 20 // Always return the old value of "*ptr" | |
| 21 // | |
| 22 // This routine implies no memory barriers. | |
| 23 inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, | |
| 24 Atomic32 old_value, | |
| 25 Atomic32 new_value) { | |
| 26 Atomic32 prev, tmp; | |
| 27 __asm__ __volatile__(".set push\n" | |
| 28 ".set noreorder\n" | |
| 29 "1:\n" | |
| 30 "ll %0, %5\n" // prev = *ptr | |
| 31 "bne %0, %3, 2f\n" // if (prev != old_value) goto 2 | |
| 32 "move %2, %4\n" // tmp = new_value | |
| 33 "sc %2, %1\n" // *ptr = tmp (with atomic check) | |
| 34 "beqz %2, 1b\n" // start again on atomic error | |
| 35 "nop\n" // delay slot nop | |
| 36 "2:\n" | |
| 37 ".set pop\n" | |
| 38 : "=&r" (prev), "=m" (*ptr), "=&r" (tmp) | |
| 39 : "Ir" (old_value), "r" (new_value), "m" (*ptr) | |
| 40 : "memory"); | |
| 41 return prev; | |
| 42 } | |
| 43 | |
| 44 // Atomically store new_value into *ptr, returning the previous value held in | |
| 45 // *ptr. This routine implies no memory barriers. | |
| 46 inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, | |
| 47 Atomic32 new_value) { | |
| 48 Atomic32 temp, old; | |
| 49 __asm__ __volatile__(".set push\n" | |
| 50 ".set noreorder\n" | |
| 51 "1:\n" | |
| 52 "ll %1, %2\n" // old = *ptr | |
| 53 "move %0, %3\n" // temp = new_value | |
| 54 "sc %0, %2\n" // *ptr = temp (with atomic check) | |
| 55 "beqz %0, 1b\n" // start again on atomic error | |
| 56 "nop\n" // delay slot nop | |
| 57 ".set pop\n" | |
| 58 : "=&r" (temp), "=&r" (old), "=m" (*ptr) | |
| 59 : "r" (new_value), "m" (*ptr) | |
| 60 : "memory"); | |
| 61 | |
| 62 return old; | |
| 63 } | |
| 64 | |
| 65 // Atomically increment *ptr by "increment". Returns the new value of | |
| 66 // *ptr with the increment applied. This routine implies no memory barriers. | |
| 67 inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, | |
| 68 Atomic32 increment) { | |
| 69 Atomic32 temp, temp2; | |
| 70 | |
| 71 __asm__ __volatile__(".set push\n" | |
| 72 ".set noreorder\n" | |
| 73 "1:\n" | |
| 74 "ll %0, %2\n" // temp = *ptr | |
| 75 "addu %1, %0, %3\n" // temp2 = temp + increment | |
| 76 "sc %1, %2\n" // *ptr = temp2 (with atomic check) | |
| 77 "beqz %1, 1b\n" // start again on atomic error | |
| 78 "addu %1, %0, %3\n" // temp2 = temp + increment | |
| 79 ".set pop\n" | |
| 80 : "=&r" (temp), "=&r" (temp2), "=m" (*ptr) | |
| 81 : "Ir" (increment), "m" (*ptr) | |
| 82 : "memory"); | |
| 83 // temp2 now holds the final value. | |
| 84 return temp2; | |
| 85 } | |
| 86 | |
| 87 inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, | |
| 88 Atomic32 increment) { | |
| 89 MemoryBarrier(); | |
| 90 Atomic32 res = NoBarrier_AtomicIncrement(ptr, increment); | |
| 91 MemoryBarrier(); | |
| 92 return res; | |
| 93 } | |
| 94 | |
| 95 // "Acquire" operations | |
| 96 // ensure that no later memory access can be reordered ahead of the operation. | |
| 97 // "Release" operations ensure that no previous memory access can be reordered | |
| 98 // after the operation. "Barrier" operations have both "Acquire" and "Release" | |
| 99 // semantics. A MemoryBarrier() has "Barrier" semantics, but does no memory | |
| 100 // access. | |
| 101 inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, | |
| 102 Atomic32 old_value, | |
| 103 Atomic32 new_value) { | |
| 104 Atomic32 res = NoBarrier_CompareAndSwap(ptr, old_value, new_value); | |
| 105 MemoryBarrier(); | |
| 106 return res; | |
| 107 } | |
| 108 | |
| 109 inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, | |
| 110 Atomic32 old_value, | |
| 111 Atomic32 new_value) { | |
| 112 MemoryBarrier(); | |
| 113 return NoBarrier_CompareAndSwap(ptr, old_value, new_value); | |
| 114 } | |
| 115 | |
| 116 inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) { | |
| 117 *ptr = value; | |
| 118 } | |
| 119 | |
| 120 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) { | |
| 121 *ptr = value; | |
| 122 } | |
| 123 | |
| 124 inline void MemoryBarrier() { | |
| 125 __asm__ __volatile__("sync" : : : "memory"); | |
| 126 } | |
| 127 | |
| 128 inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { | |
| 129 *ptr = value; | |
| 130 MemoryBarrier(); | |
| 131 } | |
| 132 | |
| 133 inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) { | |
| 134 MemoryBarrier(); | |
| 135 *ptr = value; | |
| 136 } | |
| 137 | |
| 138 inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) { | |
| 139 return *ptr; | |
| 140 } | |
| 141 | |
| 142 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { | |
| 143 return *ptr; | |
| 144 } | |
| 145 | |
| 146 inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) { | |
| 147 Atomic32 value = *ptr; | |
| 148 MemoryBarrier(); | |
| 149 return value; | |
| 150 } | |
| 151 | |
| 152 inline Atomic32 Release_Load(volatile const Atomic32* ptr) { | |
| 153 MemoryBarrier(); | |
| 154 return *ptr; | |
| 155 } | |
| 156 | |
| 157 } } // namespace v8::internal | |
| 158 | |
| 159 #endif // V8_ATOMICOPS_INTERNALS_MIPS_GCC_H_ | |
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