Adds a few MIPS arithmetic instructions to the simulator, assembler, disassembler

runtime/vm/simulator_mips.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Declares a Simulator for MIPS instructions if we are not generating a native
 // MIPS binary. This Simulator allows us to run and debug MIPS code generation
 // on regular desktop machines.
 // Dart calls into generated code by "calling" the InvokeDartCode stub,
 // which will start execution in the Simulator or forwards to the real entry
 // on a MIPS HW platform.
@@ skipping 17 matching lines @@
   ~Simulator();
 
   // The currently executing Simulator instance, which is associated to the
   // current isolate
   static Simulator* Current();
 
   // Accessors for register state.
   void set_register(Register reg, int32_t value);
   int32_t get_register(Register reg) const;
 
+  // Accessors for hi, lo registers.
+  void set_hi_register(int32_t value) { hi_reg_ = value; }
+  void set_lo_register(int32_t value) { lo_reg_ = value; }
+  int32_t get_hi_register() const { return hi_reg_; }
+  int32_t get_lo_register() const { return lo_reg_; }
+
   // Accessor to the internal simulator stack top.
   uword StackTop() const;
 
   // Call on program start.
   static void InitOnce();
 
   // Dart generally calls into generated code with 5 parameters. This is a
   // convenience function, which sets up the simulator state and grabs the
   // result on return.
   int64_t Call(int32_t entry,
                int32_t parameter0,
                int32_t parameter1,
                int32_t parameter2,
                int32_t parameter3);
 
  private:
   // A pc value used to signal the simulator to stop execution.  Generally
   // the ra is set to this value on transition from native C code to
   // simulated execution, so that the simulator can "return" to the native
   // C code.
   static const uword kEndSimulatingPC = -1;
 
+  // Special registers for the results of div, divu.
+  int32_t hi_reg_;
+  int32_t lo_reg_;
+
   int32_t registers_[kNumberOfCpuRegisters];
   uword pc_;
 
   // Simulator support.
   char* stack_;
   int icount_;
   bool delay_slot_;
 
+  bool OverflowFrom(int32_t alu_out,
+                    int32_t left,
+                    int32_t right,
+                    bool addition);
+
   void set_pc(uword value) { pc_ = value; }
 
   void Format(Instr* instr, const char* format);
 
   void DecodeSpecial(Instr* instr);
+  void DecodeSpecial2(Instr* instr);
   void InstructionDecode(Instr* instr);
 
   void Execute();
   void ExecuteDelaySlot();
 };
 
 }  // namespace dart
 
 #endif  // VM_SIMULATOR_MIPS_H_