protected void OnExpire(TimerExpirationEventArgs args)
{
if (Expired != null)
{
Expired(this, args);
}
}
private void DisplayEndOfFrame(object sender, TimerExpirationEventArgs e)
{
TimerExpired(sender, e);
currentLcdDmaCounter = 0;
currentLine = Timers[2].BackupValue;
device.NewVideoFrameAvailable = true;
}
private void TimerExpired(object sender, TimerExpirationEventArgs e)
{
Timer timer = (Timer)sender;
// Only timers with enabled interrupt will trigger
if (timer.StaticControlBits.EnableInterrupt)
{
// Update interrupt status
timerInterruptStatusRegister |= e.InterruptMask;
// Trigger a maskable interrupt
device.Cpu.SignalInterrupt(InterruptType.Irq);
}
}
public void GenerateBaudRate(object sender, TimerExpirationEventArgs e)
{
Timer timer = (Timer)sender;
// bool fireInterrupt = comLynx.GenerateBaudRate();
bool fireInterrupt = ComLynx.GenerateBaudPulse();
if (fireInterrupt)
{
// Update interrupt status
timerInterruptStatusRegister |= e.InterruptMask;
// Trigger a maskable interrupt
device.Cpu.SignalInterrupt(InterruptType.Irq);
}
}
// "The interrupt signal comes from the timer when the timer value is zero
// AND the timer is attempting to perform a 'borrow'."
protected ulong Expire()
{
ulong cyclesInterrupt = 0;
// "It is set on time out, reset with the reset timer done bit (xxx1, B6)"
DynamicControlBits.TimerDone = true; // !StaticControlBits.ResetTimerDone;
DynamicControlBits.BorrowOut = true;
// "Timers can be set to stop when they reach a count of 0 or to reload from their backup register."
// Reload if neccessary
CurrentValue = StaticControlBits.EnableReload ? BackupValue : (byte)0;
TimerExpirationEventArgs args = new TimerExpirationEventArgs(this.InterruptMask);
OnExpire(args);
cyclesInterrupt = args.CyclesInterrupt;
return(cyclesInterrupt);
}
private void RenderLine(object sender, TimerExpirationEventArgs e)
{
TimerExpired(sender, e);
// TODO: Implementation of Keith does not always trigger IRQ when DMA is not enabled,
// display bits (?) or display current have not been set
if (!DISPCTL.EnableVideoDma)
{
return;
}
int backupValue = Timers[2].BackupValue;
//currentLine = Timers[2].CurrentValue;
// "The current method of driving the LCD requires 3 scan lines of vertical blank."
// TODO: Determine if rest is between frames 104, 103 and 102 (for 60Hz)
// Keith Wilkins has Rest period between 102, 101 and 100
bool rest = (currentLine >= (backupValue - 4) && currentLine <= (backupValue - 2));
RestActive = rest;
//IODAT.Rest = rest;
if (currentLine > (backupValue - 3))
{
currentLine--;
return;
}
if (currentLine == (backupValue - 3))
{
// Pick up current video start address
// "The hardware address in Mikey (DISPADDR) is the backup value for the actual address counter.
// The backup value is transferred to the address counter at the very start of the third line of
// vertical blanking."
currentLynxDmaAddress = (ushort)(VideoDisplayStartAddress.Value & 0xFFFC);
// "The value in the register is the start (upper left corner) of the display buffer in normal
// mode and the end (lower right corner) of the display buffer in FLIP mode"
if (DISPCTL.Flip)
{
currentLynxDmaAddress += 3;
}
}
if (currentLine > 0)
{
currentLine--;
}
if (currentLcdDmaCounter < 0)
{
return;
}
// TODO: Define constant for DMA_READWRITE_CYCLE
e.CyclesInterrupt = 80 * 4;
// Every byte has two nibbles for two pixels
for (int loop = 0; loop < Suzy.SCREEN_WIDTH / 2; loop++)
{
byte source = VideoMemoryDma[currentLynxDmaAddress];
if (DISPCTL.Flip)
{
currentLynxDmaAddress--;
SetPixel((byte)(source & 0x0F));
SetPixel((byte)(source >> 4));
}
else
{
currentLynxDmaAddress++;
SetPixel((byte)(source >> 4));
SetPixel((byte)(source & 0x0F));
}
}
}
