예제 #1
0
        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();
        }
예제 #2
0
        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;
                }
            };
        }