Mapper029.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BizHawk.Emulation.Cores.Nintendo.NES
{
	// what is this?
	public class Mapper029 : NES.NESBoardBase
	{
		int prg;
		int chr;
		int prg_bank_mask_16k;

		public override bool Configure(NES.EDetectionOrigin origin)
		{
			switch (Cart.board_type)
			{
				case "Mapper029":
				case "UNIF_JERKFACE":
				case "UNIF_RET-CUFROM":
					break;
				default:
					return false;
			}
			SetMirrorType(EMirrorType.Vertical);
			AssertChr(0);
			AssertPrg(32, 64, 128, 256, 512, 1024);
			Cart.wram_size = 8;
			Cart.vram_size = 32;
			prg_bank_mask_16k = Cart.prg_size / 16 - 1;
			return true;
		}

		public override void WritePRG(int addr, byte value)
		{
			chr = value & 3;
			prg = (value >> 2) & prg_bank_mask_16k;
		}

		public override byte ReadPRG(int addr)
		{
			int bank = addr >= 0x4000 ? prg_bank_mask_16k : prg;
			return ROM[bank << 14 | addr & 0x3fff];
		}
		public override byte ReadPPU(int addr)
		{
			if (addr < 0x2000)
				return VRAM[addr | chr << 13];
			else
				return base.ReadPPU(addr);
		}
		public override void WritePPU(int addr, byte value)
		{
			if (addr < 0x2000)
				VRAM[addr | chr << 13] = value;
			else
				base.WritePPU(addr, value);
		}
	}
}