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Diffstat (limited to 'base/atomicops_internals_mips_gcc.h')
| -rw-r--r-- | base/atomicops_internals_mips_gcc.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/base/atomicops_internals_mips_gcc.h b/base/atomicops_internals_mips_gcc.h new file mode 100644 index 0000000..2bcddf7 --- /dev/null +++ b/base/atomicops_internals_mips_gcc.h @@ -0,0 +1,162 @@ +// Copyright (c) 2009 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +// This file is an internal atomic implementation, use base/atomicops.h instead. +// +// LinuxKernelCmpxchg and Barrier_AtomicIncrement are from Google Gears. + +#ifndef BASE_ATOMICOPS_INTERNALS_MIPS_GCC_H_ +#define BASE_ATOMICOPS_INTERNALS_MIPS_GCC_H_ +#pragma once + +#define ATOMICOPS_COMPILER_BARRIER() __asm__ __volatile__("" : : : "memory") + +namespace base { +namespace subtle { + +// Atomically execute: +// result = *ptr; +// if (*ptr == old_value) +// *ptr = new_value; +// return result; +// +// I.e., replace "*ptr" with "new_value" if "*ptr" used to be "old_value". +// Always return the old value of "*ptr" +// +// This routine implies no memory barriers. +inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, + Atomic32 old_value, + Atomic32 new_value) { + Atomic32 prev, tmp; + __asm__ __volatile__(".set push\n" + ".set noreorder\n" + "1:\n" + "ll %0, %5\n" // prev = *ptr + "bne %0, %3, 2f\n" // if (prev != old_value) goto 2 + "move %2, %4\n" // tmp = new_value + "sc %2, %1\n" // *ptr = tmp (with atomic check) + "beqz %2, 1b\n" // start again on atomic error + "nop\n" // delay slot nop + "2:\n" + ".set pop\n" + : "=&r" (prev), "=m" (*ptr), "=&r" (tmp) + : "Ir" (old_value), "r" (new_value), "m" (*ptr) + : "memory"); + return prev; +} + +// Atomically store new_value into *ptr, returning the previous value held in +// *ptr. This routine implies no memory barriers. +inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, + Atomic32 new_value) { + Atomic32 temp, old; + __asm__ __volatile__(".set push\n" + ".set noreorder\n" + "1:\n" + "ll %1, %2\n" // old = *ptr + "move %0, %3\n" // temp = new_value + "sc %0, %2\n" // *ptr = temp (with atomic check) + "beqz %0, 1b\n" // start again on atomic error + "nop\n" // delay slot nop + ".set pop\n" + : "=&r" (temp), "=&r" (old), "=m" (*ptr) + : "r" (new_value), "m" (*ptr) + : "memory"); + + return old; +} + +// Atomically increment *ptr by "increment". Returns the new value of +// *ptr with the increment applied. This routine implies no memory barriers. +inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, + Atomic32 increment) { + Atomic32 temp, temp2; + + __asm__ __volatile__(".set push\n" + ".set noreorder\n" + "1:\n" + "ll %0, %2\n" // temp = *ptr + "addu %1, %0, %3\n" // temp2 = temp + increment + "sc %1, %2\n" // *ptr = temp2 (with atomic check) + "beqz %1, 1b\n" // start again on atomic error + "addu %1, %0, %3\n" // temp2 = temp + increment + ".set pop\n" + : "=&r" (temp), "=&r" (temp2), "=m" (*ptr) + : "Ir" (increment), "m" (*ptr) + : "memory"); + // temp2 now holds the final value. + return temp2; +} + +inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, + Atomic32 increment) { + ATOMICOPS_COMPILER_BARRIER(); + Atomic32 res = NoBarrier_AtomicIncrement(ptr, increment); + ATOMICOPS_COMPILER_BARRIER(); + return res; +} + +// "Acquire" operations +// ensure that no later memory access can be reordered ahead of the operation. +// "Release" operations ensure that no previous memory access can be reordered +// after the operation. "Barrier" operations have both "Acquire" and "Release" +// semantics. A MemoryBarrier() has "Barrier" semantics, but does no memory +// access. +inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, + Atomic32 old_value, + Atomic32 new_value) { + ATOMICOPS_COMPILER_BARRIER(); + Atomic32 res = NoBarrier_CompareAndSwap(ptr, old_value, new_value); + ATOMICOPS_COMPILER_BARRIER(); + return res; +} + +inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, + Atomic32 old_value, + Atomic32 new_value) { + ATOMICOPS_COMPILER_BARRIER(); + Atomic32 res = NoBarrier_CompareAndSwap(ptr, old_value, new_value); + ATOMICOPS_COMPILER_BARRIER(); + return res; +} + +inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) { + *ptr = value; +} + +inline void MemoryBarrier() { + __asm__ __volatile__("sync" : : : "memory"); +} + +inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) { + *ptr = value; + MemoryBarrier(); +} + +inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) { + MemoryBarrier(); + *ptr = value; +} + +inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { + return *ptr; +} + +inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) { + Atomic32 value = *ptr; + MemoryBarrier(); + return value; +} + +inline Atomic32 Release_Load(volatile const Atomic32* ptr) { + MemoryBarrier(); + return *ptr; +} + +} // namespace base::subtle +} // namespace base + +#undef ATOMICOPS_COMPILER_BARRIER + +#endif // BASE_ATOMICOPS_INTERNALS_MIPS_GCC_H_ |