MIPS: updated atomic operations.

src/atomicops_internals_mips_gcc.h

 // 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
@@ skipping 12 matching lines @@
 // 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__("sync" : : : "memory")
+#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;
-  __asm__ __volatile__("1:\n"
-                       "ll %0, %1\n"  // prev = *ptr
+  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
-                       "nop\n"  // delay slot nop
-                       "sc %2, %1\n"  // *ptr = new_value (with atomic check)
+                       "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"
-                       : "=&r" (prev), "=m" (*ptr), "+&r" (new_value)
+                       ".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__("1:\n"
+  __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__("1:\n"
+  __asm__ __volatile__(".set push\n"
+                       ".set noreorder\n"
+                       "1:\n"
                        "ll %0, %2\n"  // temp = *ptr
-                       "addu %0, %3\n"  // temp = temp + increment
-                       "move %1, %0\n"  // temp2 = temp
-                       "sc %0, %2\n"  // *ptr = temp (with atomic check)
-                       "beqz %0, 1b\n"  // start again on atomic error
-                       "nop\n"  // delay slot nop
+                       "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) {
-  Atomic32 x = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
   ATOMICOPS_COMPILER_BARRIER();
-  return x;
+  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();
-  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+  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() {
-  ATOMICOPS_COMPILER_BARRIER();
+  __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;
@@ skipping 12 matching lines @@
 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_