Clarify precedence of operations involving bitwise and(&) in x64/assembler.

src/x64/assembler-x64.cc

 // Copyright 2009 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 1003 matching lines @@
   emit_operand(0, dst);
   emit(value);
 }
 
 
 void Assembler::movq(Register dst, Handle<Object> value, RelocInfo::Mode mode) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   ASSERT(!Heap::InNewSpace(*value));
   emit_rex_64(dst);
-  emit(0xB8 | dst.code() & 0x7);
+  emit(0xB8 | (dst.code() & 0x7));
   if (value->IsHeapObject()) {
     emitq(reinterpret_cast<uintptr_t>(value.location()), mode);
   } else {
     ASSERT_EQ(RelocInfo::NONE, mode);
     emitq(reinterpret_cast<uintptr_t>(*value), RelocInfo::NONE);
   }
 }
 
 
 void Assembler::movsxlq(Register dst, Register src) {
@@ skipping 858 matching lines @@
 void JumpTarget::DoBranch(Condition a, Hint b) {
   UNIMPLEMENTED();
 }
 
 void JumpTarget::DoJump() {
   UNIMPLEMENTED();
 }
 
 
 } }  // namespace v8::internal