Exemple #1
0
        public void UpdateState(Keys pressed, Memory memory)
        {
            Keys newPressed = (pressed ^ CurrentState) & pressed;

            CurrentState = pressed;
            if (newPressed != Keys.None)
            {
                CPU.RequestInterrupt(memory, CPU.Interrupt.Joypad);
            }
        }
Exemple #2
0
        public void Update(int cpuCycles)
        {
            byte controlRegister = memory.ReadByte(0xFF40);

            if (controlRegister.IsBitSet(7) == false)
            {
                // Disabling LCD can be only done during VBlank
                CurrentMode = Mode.VBlank;
                cycles      = 456;
                CurrentLine = 0;
                windowLine  = 0;
                return;
            }

            cycles += cpuCycles;
            switch (CurrentMode)
            {
            case Mode.OamSearch:
                if (cycles >= 80)
                {
                    CurrentMode = Mode.PixelTransfer;
                    cycles     -= 80;
                }
                break;

            case Mode.PixelTransfer:
                if (cycles >= 172)
                {
                    CurrentMode = Mode.HBlank;
                    cycles     -= 172;

                    RenderScanLine(controlRegister);
                }
                break;

            case Mode.HBlank:
                if (cycles >= 204)
                {
                    CurrentLine++;

                    cycles -= 204;
                    if (CurrentLine == HEIGHT)
                    {
                        CurrentMode = Mode.VBlank;

                        CPU.RequestInterrupt(memory, CPU.Interrupt.VBlank);
                        RenderEvent?.Invoke();
                    }
                    else
                    {
                        CurrentMode = Mode.OamSearch;
                    }
                }
                break;

            case Mode.VBlank:
                if (cycles >= 456)
                {
                    cycles -= 456;
                    // Not really rendering anything but the line counter keeps updating during the V-Blank period
                    if (CurrentLine == 153)
                    {
                        CurrentMode = Mode.OamSearch;
                        CurrentLine = 0;
                        windowLine  = 0;
                    }
                    else
                    {
                        CurrentLine++;
                    }
                }


                break;
            }
        }