public override void StepVideo(int scanLine, int cycle, bool showBackground, bool showSprites)
{
cpuClock++;
cpuClock %= 3;
// using priming variable synchronises IRQ timing and prevents jitter
if (irqPrimed && cycle == 0)
{
TriggerInterruptRequest?.Invoke();
irqPrimed = false;
}
if (!irqCounterEnabled || cpuClock != 0)
{
return;
}
ushort fixedBits = (ushort)(irqCounter & irqFixedMask);
ushort counterbits = (ushort)(irqCounter & irqCounterMask);
if (counterbits == 0)
{
irqPrimed = true;
}
--counterbits;
irqCounter = (ushort)(fixedBits | (counterbits & irqCounterMask));
}
public override void StepVideo(int scanLine, int cycle, bool showBackground, bool showSprites)
{
if (cycle != 332)
return;
if (irqReloadPrimed)
{
irqCounter = irqReload;
irqReloadPrimed = false;
}
if (scanLine > 239 && scanLine < 261)
return;
if (!showBackground && !showSprites)
return;
if (irqCounter == 0)
{
irqCounter = irqReload;
}
else
{
--irqCounter;
if (irqCounter == 0 && irqEnabled)
TriggerInterruptRequest?.Invoke();
}
}
public override void StepVideo(int scanLine, int cycle, bool showBackground, bool showSprites)
{
ppuRendering = scanLine >= 0 && scanLine < 240 && (showBackground || showSprites);
if (cycle != 0)
{
return;
}
if (ppuRendering)
{
if (!inFrame)
{
inFrame = true;
irqCounter = 0;
CancelInterruptRequest?.Invoke();
}
else
{
++irqCounter;
if (irqCounter == irqLatch)
{
irqPending = true;
if (irqEnabled)
{
TriggerInterruptRequest?.Invoke();
}
}
}
}
else
{
inFrame = false;
}
}
public override void StepVideo(int scanLine, int cycle, bool showBackground, bool showSprites)
{
cpuClock++;
cpuClock %= 3;
if (cpuClock != 0)
{
return;
}
if (irqCounter < 0x7FFF)
{
++irqCounter;
}
else if (irqEnabled)
{
if (!irqTriggered)
{
TriggerInterruptRequest?.Invoke();
irqTriggered = true;
}
}
if (isNamco129Or163)
{
soundChip.Update(1);
}
/*
* int output = soundChip.Output;
* Debug.WriteLineIf(output != 0, "Sound Output = " + output);
* WriteAudioSample(output * 0.1f);
*/
}
private void HandleScanLine()
{
if (irqCounter == 0)
{
irqCounter = irqReload;
}
else
{
--irqCounter;
if (irqCounter == 0 && irqEnable)
{
TriggerInterruptRequest?.Invoke();
}
}
}
private void UpdateIrqCounter()
{
if (irqCounter == 0xFF)
{
irqCounter = irqReloadValue;
Debug.WriteLine("IRQ counter reloaded to " + irqReloadValue);
if (!irqTriggered)
{
TriggerInterruptRequest?.Invoke();
irqTriggered = true;
}
}
else
{
++irqCounter;
}
}
public override void StepVideo(int scanLine, int cycle, bool showBackground, bool showSprites)
{
++cpuClock;
cpuClock %= 3;
if (cpuClock != 0)
{
return;
}
if (irqEnabled)
{
++irqCounter;
if (irqCounter >= 4096)
{
TriggerInterruptRequest?.Invoke();
}
}
}
private void StepFrameCounter()
{
if (framePeriod == 4)
{
++frameValue;
frameValue %= 4;
StepEnvelope();
if (frameValue == 1)
{
StepSweep();
StepLength();
}
else if (frameValue == 3)
{
StepSweep();
StepLength();
if (frameIrq)
{
TriggerInterruptRequest?.Invoke();
}
}
}
else if (framePeriod == 5)
{
++frameValue;
frameValue %= 5;
if (frameValue != 4)
{
StepEnvelope();
}
if (frameValue == 0 || frameValue == 2)
{
StepSweep();
StepLength();
}
}
}
