/// <summary>
/// This function executes an instruction by calling its delegate function
/// </summary>
public void ExecuteInstruction()
{
try
{
Console.WriteLine("Executing instruction");
logicalAddress = currentIndex * 4;
Console.WriteLine(logicalAddress);
currentInstruction =
program.Instructions.Where(x => x.LogicalAddress == logicalAddress).FirstOrDefault();
if (currentInstruction != null)
{
if (CurrentInstruction.Execute == null)
{
BindInstructionDelegates(ref program);
}
if (currentInstruction.Opcode == (int)EnumOpcodes.JMP ||
currentInstruction.Opcode == (int)EnumOpcodes.JEQ ||
currentInstruction.Opcode == (int)EnumOpcodes.JNE ||
currentInstruction.Opcode == (int)EnumOpcodes.JGT ||
currentInstruction.Opcode == (int)EnumOpcodes.JGE ||
currentInstruction.Opcode == (int)EnumOpcodes.JLT ||
currentInstruction.Opcode == (int)EnumOpcodes.JLE ||
currentInstruction.Opcode == (int)EnumOpcodes.JNZ ||
currentInstruction.Opcode == (int)EnumOpcodes.JZR)
// if we are executing a jump instruction do not increment the program counter
{
//program.Instructions.ElementAt(currentIndex).Execute();
currentInstruction.Execute();
}
else // otherwise increment the program counter
{
//program.Instructions.ElementAt(currentIndex).Execute();
currentInstruction.Execute();
currentIndex++;
}
SpecialRegister.FindSpecialRegister("PC")
.SetRegisterValue(currentInstruction.LogicalAddress, EnumOperandType.VALUE);
SpecialRegister.FindSpecialRegister("IR")
.SetRegisterValue(currentInstruction.InstructionString, EnumOperandType.VALUE);
SpecialRegister.FindSpecialRegister("MDR")
.SetRegisterValue(currentInstruction.InstructionString, EnumOperandType.VALUE);
SpecialRegister.FindSpecialRegister("MAR")
.SetRegisterValue(currentInstruction.PhysicalAddress, EnumOperandType.VALUE);
if (currentIndex == program.Instructions.Count)
{
Done = true;
}
Thread.Sleep(clockSpeed);
}
else
{
Done = true;
}
}
catch (Exception ex)
{
Console.WriteLine(ex.StackTrace);
}
}
/// <summary>
/// Constructor for execution unit that starts executing from the beginning of the program
/// </summary>
/// <param name="program"> the program to execute </param>
/// <param name="clockSpeed"> the clock speed of the CPU </param>
public ExecutionUnit(SimulatorProgram program, int clockSpeed)
{
try
{
this.program = program;
this.clockSpeed = clockSpeed;
currentIndex = 0;
logicalAddress = currentIndex * 4;
currentInstruction =
program.Instructions.Where(x => x.LogicalAddress == logicalAddress).FirstOrDefault();
stop = false;
done = false;
SpecialRegister.FindSpecialRegister("BR").SetRegisterValue(program.BaseAddress, EnumOperandType.ADDRESS);
}
catch (Exception e)
{
Console.WriteLine(e.StackTrace);
MessageBox.Show("Please load a program before running the CPU");
}
}
