Add mips64 port.

src/base/atomicops.h

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // The routines exported by this module are subtle.  If you use them, even if
 // you get the code right, it will depend on careful reasoning about atomicity
 // and memory ordering; it will be less readable, and harder to maintain.  If
 // you plan to use these routines, you should have a good reason, such as solid
 // evidence that performance would otherwise suffer, or there being no
 // alternative.  You should assume only properties explicitly guaranteed by the
@@ skipping 130 matching lines @@
 #elif defined(__APPLE__)
 #include "src/base/atomicops_internals_mac.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_ARM64
 #include "src/base/atomicops_internals_arm64_gcc.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_ARM
 #include "src/base/atomicops_internals_arm_gcc.h"
 #elif defined(__GNUC__) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
 #include "src/base/atomicops_internals_x86_gcc.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_MIPS
 #include "src/base/atomicops_internals_mips_gcc.h"
+#elif defined(__GNUC__) && V8_HOST_ARCH_MIPS64
+#include "src/base/atomicops_internals_mips64_gcc.h"
 #else
 #error "Atomic operations are not supported on your platform"
 #endif
 
 // On some platforms we need additional declarations to make
 // AtomicWord compatible with our other Atomic* types.
 #if defined(__APPLE__) || defined(__OpenBSD__)
 #include "src/base/atomicops_internals_atomicword_compat.h"
 #endif
 
 #endif  // V8_BASE_ATOMICOPS_H_