MIPS64: Prepare additonal code for turbofan landing.

src/mips64/disasm-mips64.cc

 // Copyright 2012 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.
 
 // A Disassembler object is used to disassemble a block of code instruction by
 // instruction. The default implementation of the NameConverter object can be
 // overriden to modify register names or to do symbol lookup on addresses.
 //
 // The example below will disassemble a block of code and print it to stdout.
 //
@@ skipping 945 matching lines @@
     case SPECIAL3:
       switch (instr->FunctionFieldRaw()) {
         case INS: {
           Format(instr, "ins     'rt, 'rs, 'sa, 'ss2");
           break;
         }
         case EXT: {
           Format(instr, "ext     'rt, 'rs, 'sa, 'ss1");
           break;
         }
+        case DEXT: {
+          Format(instr, "dext    'rt, 'rs, 'sa, 'ss1");
+          break;
+        }
         default:
           UNREACHABLE();
       }
       break;
     default:
       UNREACHABLE();
   }
   return Instruction::kInstrSize;
 }
 
@@ skipping 519 matching lines @@
         prev_pc, *reinterpret_cast<int32_t*>(prev_pc), buffer.start());
   }
 }
 
 
 #undef UNSUPPORTED
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_MIPS64