AxibugEmuOnline/AxibugEmuOnline.Client/Assets/MyNes.Core/Mapper073.cs

using System.IO;

namespace MyNes.Core
{
    [BoardInfo("VRC3", 73)]
    internal class Mapper073 : Board
    {
    	private bool irq_mode_8;

    	private bool irq_enable;

    	private bool irq_enable_on_ak;

    	private int irq_reload;

    	private int irq_counter;

    	internal override void HardReset()
    	{
    		base.HardReset();
    		Switch16KPRG(PRG_ROM_16KB_Mask, PRGArea.AreaC000);
    		irq_mode_8 = false;
    		irq_enable = false;
    		irq_enable_on_ak = false;
    		irq_reload = 0;
    		irq_counter = 0;
    	}

    	internal override void WritePRG(ref ushort address, ref byte data)
    	{
    		switch (address & 0xF000)
    		{
    		case 32768:
    			irq_reload = (irq_reload & 0xFFF0) | (data & 0xF);
    			break;
    		case 36864:
    			irq_reload = (irq_reload & 0xFF0F) | ((data & 0xF) << 4);
    			break;
    		case 40960:
    			irq_reload = (irq_reload & 0xF0FF) | ((data & 0xF) << 8);
    			break;
    		case 45056:
    			irq_reload = (irq_reload & 0xFFF) | ((data & 0xF) << 12);
    			break;
    		case 49152:
    			irq_mode_8 = (data & 4) == 4;
    			irq_enable = (data & 2) == 2;
    			irq_enable_on_ak = (data & 1) == 1;
    			if (irq_enable)
    			{
    				irq_counter = irq_reload;
    			}
    			NesEmu.IRQFlags &= -9;
    			break;
    		case 53248:
    			irq_enable = irq_enable_on_ak;
    			NesEmu.IRQFlags &= -9;
    			break;
    		case 61440:
    			Switch16KPRG(data & 0xF, PRGArea.Area8000);
    			break;
    		}
    	}

    	internal override void OnCPUClock()
    	{
    		if (!irq_enable)
    		{
    			return;
    		}
    		if (irq_mode_8)
    		{
    			irq_counter = (irq_counter & 0xFF00) | (byte)((irq_counter & 0xFF) + 1);
    			if ((byte)(irq_counter & 0xFF) == byte.MaxValue)
    			{
    				NesEmu.IRQFlags |= 8;
    				irq_counter = (irq_counter & 0xFF00) | (irq_reload & 0xFF);
    			}
    		}
    		else
    		{
    			irq_counter++;
    			if (irq_counter == 65535)
    			{
    				NesEmu.IRQFlags |= 8;
    				irq_counter = irq_reload;
    			}
    		}
    	}

    	internal override void WriteStateData(ref BinaryWriter stream)
    	{
    		base.WriteStateData(ref stream);
    		stream.Write(irq_mode_8);
    		stream.Write(irq_enable);
    		stream.Write(irq_enable_on_ak);
    		stream.Write(irq_reload);
    		stream.Write(irq_counter);
    	}

    	internal override void ReadStateData(ref BinaryReader stream)
    	{
    		base.ReadStateData(ref stream);
    		irq_mode_8 = stream.ReadBoolean();
    		irq_enable = stream.ReadBoolean();
    		irq_enable_on_ak = stream.ReadBoolean();
    		irq_reload = stream.ReadInt32();
    		irq_counter = stream.ReadInt32();
    	}
    }
}