how to make simulator in C++

Assuming you have a CPU with instruction set of the following form (where A, B, D are various forms of memory, pc-relative, register, constant access, etc.):
- Op
- Op A
- Op -> D
- Op A -> D
- Op A,B
- Op A,B -> D

Pseudo Code:

class CPUModel
{
   typedef unsigned long Register;
   typedef unsigned long Value;
   class Registers
   {
      Register PC;
      ...
   }
   class Operation
   {
      enum OpCode { ... }
      enum Kind { Reg, Rel, Abs, Const, ... }
      class Source
      {
         Value value;
         Kind kind;
         ...
         Value Get()
         {
             switch(kind)
             {
                case Const:
                   return value;
                case Reg:
                   return Cpu.Registers[value];
                case Rel:
                   return Sys.Memory[Cpu.Registers.PC + value];
                case Abs:
                   return Sys.Memory[value];
                ...
             }
         }
      }
      class Destination
      {
         Value value;
         Kind kind;
         ...
         void Set(Value v)
         {
             switch(kind)
             {
                case Reg:
                   Cpu.Registers[value] = v;
                   break;
                case Rel:
                   Sys.Memory[Cpu.Registers.PC + value] = v;
                   break;
                case Abs:
                   Sys.Memory[value] = v;
                   break;
                ...
             }
         }
      }
      ...
      Operation(Word w)
      {
          code = DecodeOp(w);
          src1 = Source.DecodeFirst(w);
          src2 = Source.DecodeSecond(w);
          dest = Destination.Decode(w);
      }
   }
   void Run(Address loc)
   {
       Registers.PC = loc;
       Halt = false;
       while (!Halt)
       {
           FetchDecodeAndExecute();
           sys.DumpSystemState();
       }
   }
   void FetchDecodeAndExecute()
   {
       Word w = Sys.Memory[Registers.PC];
       Operation op = new Operation(w);
       Execute(op);
   }
   void Execute(Operation op)
   {
       switch(op.code)
       {
          case Halt:
              Halt = true;
              break;
          case Add:
              op.dest.Set(op.src1.Get() + op.src2.Get());
              Registers.PC += op.Length();
              break;
          ...
          case Jump:
              Registers.PC = op.src1.Get();
              break;
          ...
       }
   }
}
class MemoryModel
{
   ...
}
class DeviceXModel
{
   ...
}
class System
{
    ...
    System()
    {
    }
    void Init()
    {
       Cpu = new CPUModel(this);
       Mem = new MemoryModel(this);
       DevX = new DeviceXModel(this);
       ...
    }
    void Run(Address loc)
    {
        Cpu.Run(loc);
    }
}
void Simulate(File image file, Addrsss loc)
{
    System sys = new System();
    sys.Init();
    sys.LoadImageIntoMemory(loc, imageFile);
    sys.Run(loc);
}

Have Fun!

Cheers
Andi