public static void RunClock()
{
//Finished running if PC has exceeded instructions and all previous instructions have already finished running (determined by empty instruction queue)
if (!IsReady || (PC.Counter >= Instructions.Count && InstructionQueue.Count == 0))
{
return;
}
AwaitingRegisters.Clear();
ForwardedRegisters.Clear();
if (PC.Counter < Instructions.Count && !_isStalled)
{
Instructions[PC.Counter].Initialize(_clockCycle);
InstructionQueue.Enqueue(Instructions[PC.Counter]);
}
Instruction[] instructionQueueArray = InstructionQueue.ToArray();
bool isJumpTaken = false;
int jumpIndex = 0;
_isStalled = false;
//Run other stages for previous instructions in queue
for (int i = 0; i < instructionQueueArray.Length; ++i)
{
Instruction instruction = instructionQueueArray[i];
//If stall is needed do not advance any further instructions
if (!instruction.AdvanceClock())
{
_isStalled = true;
break;
}
//Mark register as awaiting values
if (instruction.WriteAwaiting != -1)
{
AwaitingRegisters.Add(instruction.WriteAwaiting);
}
//Add forwarded values
if (instruction.ForwardedRegister.HasValue)
{
ForwardedRegisters[instruction.WriteAwaiting] = instruction.ForwardedRegister.Value;
}
if (instruction.IsJumpTaken() && !isJumpTaken)
{
var jumpData = instruction.GetJumpData();
if (jumpData.Type == Instruction.JumpType.Branch)
{
PC.Advance(jumpData.Address);
}
else if (jumpData.Type == Instruction.JumpType.Jump)
{
PC.Jump(jumpData.Address);
}
isJumpTaken = true;
jumpIndex = i;
}
}
//Discards instructions after jump or branch statement
if (isJumpTaken)
{
InstructionQueue.Clear();
for (int i = 0; i < jumpIndex; ++i)
{
InstructionQueue.Enqueue(instructionQueueArray[i]);
}
}
//Dequeue finished instructions
if (instructionQueueArray[0].RelativeClock == 4)
{
InstructionQueue.Dequeue();
}
//If no jumps were taken advance program counter by 4
if (!isJumpTaken && !_isStalled)
{
PC.Advance();
}
_clockCycle++;
}
