Start Mapper 243

BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper243.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	class Mapper243 : NES.NESBoardBase
+	{
+		/*
+			Here are Disch's original notes:  
+		========================
+		=  Mapper 243          =
+		========================
+
+
+		Example Games:
+		--------------------------
+		Honey
+		Poker III 5-in-1
+
+
+		Registers:
+		---------------------------
+
+		Range,Mask:   $4020-4FFF, $4101
+
+		$4100:  [.... .AAA]   Address for use with $4101
+
+		$4101:   Data port
+		R:2 -> [.... ...H]  High bit of CHR reg
+		R:4 -> [.... ...L]  Low bit of CHR reg
+		R:5 -> [.... .PPP]  PRG reg  (32k @ $8000)
+		R:6 -> [.... ..DD]  Middle bits of CHR reg
+		R:7 -> [.... .MM.]  Mirroring
+			%00 = Horz
+			%01 = Vert
+			%10 = See below
+			%11 = 1ScB
+
+
+		Mirroring:
+		---------------------------
+
+		Mirroing mode %10 is not quite 1ScB:
+
+		[  NTA  ][  NTB  ]
+		[  NTB  ][  NTB  ]
+
+
+		CHR Setup:
+		---------------------------
+
+		8k CHR page @ $0000 is selected by the given 4 bit CHR page number ('HDDL')
+		*/
+
+		int reg_addr;
+		ByteBuffer regs = new ByteBuffer(8);
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER243":
+					break;
+				default:
+					return false;
+			}
+
+			return true;
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			ser.Sync("reg_addr", ref reg_addr);
+			ser.Sync("regs", ref regs);
+			base.SyncState(ser);
+		}
+
+		public override void WriteEXP(int addr, byte value)
+		{
+			switch (addr & 0x101)
+			{
+				case 0x0000:
+					reg_addr = addr & 0x07;
+					break;
+				case 0x0001:
+					switch (reg_addr)
+					{
+						case 0:
+							regs[0] = 0; regs[1] = 3; //FCEUX does this
+							break;
+						case 2:
+							regs[3] = (byte)((value & 0x01) << 3);
+							break;
+						case 4:
+							regs[1] = (byte)((regs[1] & 0x06) | (value & 0x03));
+							break;
+						case 5:
+							regs[0] = (byte)(value & 0x01);
+							break;
+						case 6:
+							regs[1] = (byte)((regs[1] & 0x01) | (regs[3] | (value & 0x03) << 1));
+							break;
+						case 7:
+							regs[2] = (byte)(value & 0x01);
+							break;
+
+					}
+
+					int mirror = (value >> 1) & 0x03;
+					switch (mirror)
+					{
+						case 0:
+							SetMirrorType(EMirrorType.Horizontal);
+							break;
+						case 1:
+							SetMirrorType(EMirrorType.Vertical);
+							break;
+						case 2:
+							SetMirroring(0, 1, 1, 1);
+							break;
+						case 3:
+							SetMirrorType(EMirrorType.OneScreenB);
+							break;
+					}
+					break;
+			}
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+			{
+				int chr_bank = regs[4] | (regs[6] << 1) | (regs[2] << 3);
+				return VROM[(chr_bank * 0x2000) + addr];
+			}
+			else
+			{
+				return base.ReadPPU(addr);
+			}
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			return ROM[(regs[5] * 0x8000) + addr];
+		}
+	}
+}