1b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// Copyright 2010 the V8 project authors. All rights reserved. 2b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch// Use of this source code is governed by a BSD-style license that can be 3b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch// found in the LICENSE file. 4b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 5b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// This file is an internal atomic implementation, use atomicops.h instead. 6b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 7b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch#ifndef V8_BASE_ATOMICOPS_INTERNALS_X86_GCC_H_ 8b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch#define V8_BASE_ATOMICOPS_INTERNALS_X86_GCC_H_ 9b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 10257744e915dfc84d6d07a6b2accf8402d9ffc708Ben Murdochnamespace v8 { 11b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdochnamespace base { 12257744e915dfc84d6d07a6b2accf8402d9ffc708Ben Murdoch 13b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// This struct is not part of the public API of this module; clients may not 14b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// use it. 15b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// Features of this x86. Values may not be correct before main() is run, 16b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// but are set conservatively. 17b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochstruct AtomicOps_x86CPUFeatureStruct { 18b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch bool has_amd_lock_mb_bug; // Processor has AMD memory-barrier bug; do lfence 19b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // after acquire compare-and-swap. 20b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch#if !defined(__SSE2__) 21b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch bool has_sse2; // Processor has SSE2. 22b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch#endif 23b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch}; 24b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochextern struct AtomicOps_x86CPUFeatureStruct AtomicOps_Internalx86CPUFeatures; 25b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 26b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch#define ATOMICOPS_COMPILER_BARRIER() __asm__ __volatile__("" : : : "memory") 27b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 28b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// 32-bit low-level operations on any platform. 29b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 30b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, 31b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 old_value, 32b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 new_value) { 33b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 prev; 34b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lock; cmpxchgl %1,%2" 35b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "=a" (prev) 36b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "q" (new_value), "m" (*ptr), "0" (old_value) 37b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "memory"); 38b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return prev; 39b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 40b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 41b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, 42b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 new_value) { 43b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("xchgl %1,%0" // The lock prefix is implicit for xchg. 44b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "=r" (new_value) 45b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "m" (*ptr), "0" (new_value) 46b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "memory"); 47b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return new_value; // Now it's the previous value. 48b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 49b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 50b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, 51b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 increment) { 52b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 temp = increment; 53b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lock; xaddl %0,%1" 54b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "+r" (temp), "+m" (*ptr) 55b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : : "memory"); 56b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // temp now holds the old value of *ptr 57b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return temp + increment; 58b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 59b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 60b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, 61b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 increment) { 62b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 temp = increment; 63b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lock; xaddl %0,%1" 64b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "+r" (temp), "+m" (*ptr) 65b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : : "memory"); 66b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // temp now holds the old value of *ptr 67b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch if (AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug) { 68b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lfence" : : : "memory"); 69b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } 70b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return temp + increment; 71b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 72b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 73b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, 74b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 old_value, 75b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 new_value) { 76b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 x = NoBarrier_CompareAndSwap(ptr, old_value, new_value); 77b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch if (AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug) { 78b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lfence" : : : "memory"); 79b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } 80b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return x; 81b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 82b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 83b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, 84b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 old_value, 85b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 new_value) { 86b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return NoBarrier_CompareAndSwap(ptr, old_value, new_value); 87b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 88b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 89b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdochinline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) { 90b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch *ptr = value; 91b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch} 92b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch 93b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) { 94b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch *ptr = value; 95b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 96b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 97b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch#if defined(__x86_64__) || defined(__SSE2__) 98b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 99b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// 64-bit implementations of memory barrier can be simpler, because it 100b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// "mfence" is guaranteed to exist. 101b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void MemoryBarrier() { 102b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("mfence" : : : "memory"); 103b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 104b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 105b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { 106b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch *ptr = value; 107b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch MemoryBarrier(); 108b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 109b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 110b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch#else 111b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 112b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void MemoryBarrier() { 113b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch if (AtomicOps_Internalx86CPUFeatures.has_sse2) { 114b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("mfence" : : : "memory"); 115b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } else { // mfence is faster but not present on PIII 116b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 x = 0; 117b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch NoBarrier_AtomicExchange(&x, 0); // acts as a barrier on PIII 118b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } 119b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 120b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 121b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { 122b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch if (AtomicOps_Internalx86CPUFeatures.has_sse2) { 123b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch *ptr = value; 124b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("mfence" : : : "memory"); 125b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } else { 126b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch NoBarrier_AtomicExchange(ptr, value); 127b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // acts as a barrier on PIII 128b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } 129b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 130b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch#endif 131b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 132b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void Release_Store(volatile Atomic32* ptr, Atomic32 value) { 133b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch ATOMICOPS_COMPILER_BARRIER(); 134b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch *ptr = value; // An x86 store acts as a release barrier. 135b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // See comments in Atomic64 version of Release_Store(), below. 136b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 137b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 138b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdochinline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) { 139b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch return *ptr; 140b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch} 141b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch 142b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { 143b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return *ptr; 144b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 145b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 146b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 Acquire_Load(volatile const Atomic32* ptr) { 147b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic32 value = *ptr; // An x86 load acts as a acquire barrier. 148b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // See comments in Atomic64 version of Release_Store(), below. 149b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch ATOMICOPS_COMPILER_BARRIER(); 150b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return value; 151b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 152b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 153b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic32 Release_Load(volatile const Atomic32* ptr) { 154b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch MemoryBarrier(); 155b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return *ptr; 156b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 157b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 158b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch#if defined(__x86_64__) && defined(V8_HOST_ARCH_64_BIT) 159b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 160b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch// 64-bit low-level operations on 64-bit platform. 161b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 162b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr, 163b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 old_value, 164b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 new_value) { 165b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 prev; 166b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lock; cmpxchgq %1,%2" 167b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "=a" (prev) 168b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "q" (new_value), "m" (*ptr), "0" (old_value) 169b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "memory"); 170b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return prev; 171b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 172b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 173b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr, 174b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 new_value) { 175b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("xchgq %1,%0" // The lock prefix is implicit for xchg. 176b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "=r" (new_value) 177b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "m" (*ptr), "0" (new_value) 178b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "memory"); 179b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return new_value; // Now it's the previous value. 180b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 181b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 182b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr, 183b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 increment) { 184b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 temp = increment; 185b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lock; xaddq %0,%1" 186b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "+r" (temp), "+m" (*ptr) 187b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : : "memory"); 188b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // temp now contains the previous value of *ptr 189b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return temp + increment; 190b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 191b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 192b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr, 193b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 increment) { 194b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 temp = increment; 195b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lock; xaddq %0,%1" 196b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : "+r" (temp), "+m" (*ptr) 197b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch : : "memory"); 198b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // temp now contains the previous value of *ptr 199b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch if (AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug) { 200b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lfence" : : : "memory"); 201b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } 202b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return temp + increment; 203b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 204b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 205b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) { 206b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch *ptr = value; 207b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 208b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 209b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) { 210b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch *ptr = value; 211b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch MemoryBarrier(); 212b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 213b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 214b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline void Release_Store(volatile Atomic64* ptr, Atomic64 value) { 215b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch ATOMICOPS_COMPILER_BARRIER(); 216b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 217b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch *ptr = value; // An x86 store acts as a release barrier 218b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // for current AMD/Intel chips as of Jan 2008. 219b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // See also Acquire_Load(), below. 220b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 221b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // When new chips come out, check: 222b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // IA-32 Intel Architecture Software Developer's Manual, Volume 3: 223b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // System Programming Guide, Chatper 7: Multiple-processor management, 224b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // Section 7.2, Memory Ordering. 225b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // Last seen at: 226b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // http://developer.intel.com/design/pentium4/manuals/index_new.htm 227b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // 228b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // x86 stores/loads fail to act as barriers for a few instructions (clflush 229b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // maskmovdqu maskmovq movntdq movnti movntpd movntps movntq) but these are 230b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // not generated by the compiler, and are rare. Users of these instructions 231b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // need to know about cache behaviour in any case since all of these involve 232b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // either flushing cache lines or non-temporal cache hints. 233b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 234b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 235b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) { 236b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return *ptr; 237b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 238b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 239b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 Acquire_Load(volatile const Atomic64* ptr) { 240b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 value = *ptr; // An x86 load acts as a acquire barrier, 241b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // for current AMD/Intel chips as of Jan 2008. 242b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch // See also Release_Store(), above. 243b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch ATOMICOPS_COMPILER_BARRIER(); 244b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return value; 245b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 246b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 247b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 Release_Load(volatile const Atomic64* ptr) { 248b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch MemoryBarrier(); 249b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return *ptr; 250b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 251b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 252b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr, 253b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 old_value, 254b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 new_value) { 255b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 x = NoBarrier_CompareAndSwap(ptr, old_value, new_value); 256b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch if (AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug) { 257b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch __asm__ __volatile__("lfence" : : : "memory"); 258b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch } 259b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return x; 260b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 261b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 262b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdochinline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr, 263b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 old_value, 264b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch Atomic64 new_value) { 265b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch return NoBarrier_CompareAndSwap(ptr, old_value, new_value); 266b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch} 267b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 268b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch#endif // defined(__x86_64__) 269b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 270b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch} } // namespace v8::base 271b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 272b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch#undef ATOMICOPS_COMPILER_BARRIER 273b0fe1620dcb4135ac3ab2d66ff93072373911299Ben Murdoch 274b8a8cc1952d61a2f3a2568848933943a543b5d3eBen Murdoch#endif // V8_BASE_ATOMICOPS_INTERNALS_X86_GCC_H_ 275