void CalculateWhichCycleTheTimerWillFire()
{
if (CascadeMode || !Enabled)
{
FiresOnCycle = 0xFFFFFFFF;
return;
}
UInt32 cycle = (UInt32)(gba.Cpu.Cycles + ((0xFFFF - TimerValue) * timers.TimerPeriods[Freq]));
FiresOnCycle = cycle;
// Keep track of when we next need to update timers
timers.CalculateWhenToNextUpdate();
}
public GbaTimer(Timers timers, GameboyAdvance gba, int timerNumber)
{
this.timers = timers;
this.gba = gba;
this.timerNumber = timerNumber;
FiresOnCycle = 0xFFFFFFFF;
UInt32 baseAddr = (UInt32)(0x4000100 + (timerNumber * 4));
TimerValueRegister r0 = new TimerValueRegister(gba, this, gba.Memory, baseAddr);
TimerValueRegister r1 = new TimerValueRegister(gba, this, gba.Memory, baseAddr + 1);
TimerValueRegister = new MemoryRegister16(gba.Memory, baseAddr, true, false, r0, r1);
ReloadValue = new MemoryRegister16(gba.Memory, baseAddr, false, true);
baseAddr = (UInt32)(0x4000102 + (timerNumber * 4));
MemoryRegister8WithSetHook reg = new MemoryRegister8WithSetHook(gba.Memory, baseAddr, true, true);
MemoryRegister8 unused = new MemoryRegister8(gba.Memory, baseAddr + 1, true, true);
TimerControlRegister = new MemoryRegister16(gba.Memory, baseAddr, true, true, reg, unused);
reg.OnSet = (oldValue, newValue) =>
{
CalculateWhichCycleTheTimerWillFire();
timers.CalculateWhenToNextUpdate();
// When a timer is enabled, it reloads it's starting value. When it is disabled it just maintains its current values
bool wasEnabled = ((oldValue & 0x80) != 0);
bool enabled = ((newValue & 0x80) != 0);
if (wasEnabled == false && enabled)
{
startCycle = gba.Cpu.Cycles;
timers.ScheduledUpdate();
TimerValue = ReloadValue.Value;
}
};
}
