public override void Initialize()
{
//Initialize Registers
Registers = new Registers(this);
//Initialize ALU
ALU = new ArithmeticLogicUnit(this);
//Initialize Interrupt Service
InterruptService = new InterruptService(this);
//Initialize Control Unit
ControlUnit = new ControlUnit(this);
/*
* Interrupts should be served before fetching opcodes. So we check an interrupt here
* before fetching the first opcode, as serving an interrupt in the loop before the fetch
* would not allow us to break the debugger on interrupt vectors at 40h 48h 50h etc.
*/
InterruptService.InterruptServiceRoutine();
}
/// <summary>
/// Fetches and Executes the opcode, PC is pointing at, serving interrupts or halting when needed.
/// CPU also advances IPeripheral components when needed to reflect the timing of the physical chip.
/// </summary>
public override void FetchAndExecute()
{
//Advance the components in time (fetch takes 1 machine cycle)
GetBoard().AdvanceSystemTime(); //4
//Halt will execute NOP. Essentially this is equivalent to just running the components at 4 clocks and returning
if (!Halt)
{
//Fetch: Get the current opcode from memory
byte Opcode = GetBoard().GetMemoryManagementUnit().Read(Registers.PC);
//Execute: Call the Control Unit
ControlUnit.Execute(Opcode);
}
/*
* On Game Boy, Interrupts are served first, but since it's last on the loop,
* this behaves as being first. For the first interrupt, we do an IR check in the Init() function
*/
InterruptService.InterruptServiceRoutine();
}
public override string ToString()
{
return(String.Format("PC:\t\t{0:X4}\nSP:\t\t{5:X4}\nAF:\t\t{1:X4}\nBC:\t\t{2:X4}\nDE:\t\t{3:X4}\nHL:\t\t{4:X4}\n{6}",
Registers.PC, Registers.GetAF(), Registers.GetBC(), Registers.GetDE(), Registers.GetHL(), Registers.SP, InterruptService.ToString()));
}