15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2009 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This file is an internal atomic implementation, include base/atomicops.h 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// instead. This file is for platforms that use GCC intrinsics rather than 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// platform-specific assembly code for atomic operations. 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_ATOMICOPS_INTERNALS_GCC_H_ 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_ATOMICOPS_INTERNALS_GCC_H_ 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace subtle { 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 old_value, 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 new_value) { 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 prev_value; 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) do { 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (__sync_bool_compare_and_swap(ptr, old_value, new_value)) 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return old_value; 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) prev_value = *ptr; 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } while (prev_value == old_value); 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return prev_value; 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 new_value) { 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 old_value; 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) do { 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) old_value = *ptr; 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } while (!__sync_bool_compare_and_swap(ptr, old_value, new_value)); 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return old_value; 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 increment) { 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return Barrier_AtomicIncrement(ptr, increment); 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 increment) { 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (;;) { 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Atomic exchange the old value with an incremented one. 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 old_value = *ptr; 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 new_value = old_value + increment; 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (__sync_bool_compare_and_swap(ptr, old_value, new_value)) { 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The exchange took place as expected. 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return new_value; 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Otherwise, *ptr changed mid-loop and we need to retry. 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 old_value, 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 new_value) { 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Since NoBarrier_CompareAndSwap uses __sync_bool_compare_and_swap, which 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // is a full memory barrier, none is needed here or below in Release. 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return NoBarrier_CompareAndSwap(ptr, old_value, new_value); 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 old_value, 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 new_value) { 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return NoBarrier_CompareAndSwap(ptr, old_value, new_value); 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) { 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *ptr = value; 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline void MemoryBarrier() { 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) __sync_synchronize(); 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *ptr = value; 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) MemoryBarrier(); 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) { 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) MemoryBarrier(); 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) *ptr = value; 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return *ptr; 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) { 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Atomic32 value = *ptr; 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) MemoryBarrier(); 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return value; 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)inline Atomic32 Release_Load(volatile const Atomic32* ptr) { 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) MemoryBarrier(); 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return *ptr; 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base::subtle 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_ATOMICOPS_INTERNALS_GCC_H_ 1065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 107