// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// This file is an internal atomic implementation, use atomicops.h instead.
#ifndef V8_ATOMICOPS_INTERNALS_MIPS_GCC_H_
#define V8_ATOMICOPS_INTERNALS_MIPS_GCC_H_
#define ATOMICOPS_COMPILER_BARRIER() __asm__ __volatile__("" : : : "memory")
namespace v8 {
namespace internal {
// 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 v8::internal
#undef ATOMICOPS_COMPILER_BARRIER
#endif // V8_ATOMICOPS_INTERNALS_MIPS_GCC_H_