public void Execute()
{
// get address of instruction to run
var address = Memory.GetWord(Z.Read().NativeValue);
// update Z
Z.Increment();
// we only care about 15-bit instructions
var instruction = address.Read() & 0x7FFF;
var code = (ushort)(instruction >> 12);
var K = (ushort)(instruction & 0xFFF);
// determine if this is an extra code instruction
if (ExtraCodeFlag)
{
// reset CPU for instruction to execute
extraCodeInstructions[code].CPU = this;
extraCodeInstructions[code].Execute(K);
// clear the extra code flag
ExtraCodeFlag = false;
}
else
{
// reset CPU for instruction to execute
instructions[code].CPU = this;
instructions[code].Execute(K);
}
}
/**
* @brief Writes the content of a given register to the PC.
* @param register - The register to be read from.
*/
public IEnumerator WriteToPC(Register register)
{
if (PC.Equals(register))
{
busSystem.StartTransferringData(BusControl.BUS_ROUTE.PC_PC);
yield return(new WaitForSeconds(clock.GetSpeed()));
PC.Increment();
busSystem.StopTransferringData(BusControl.BUS_ROUTE.PC_PC);
}
else
{
busSystem.StartTransferringData(register.RouteToPC);
yield return(new WaitForSeconds(clock.GetSpeed()));
PC.Write(register.ReadString());
busSystem.StopTransferringData(register.RouteToPC);
}
}