NES: Support mapper 196 (super mario bros 11, super mario bros 17, and "super mario bros jurassic park")

BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj

@@ -330,6 +330,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\MMC3_family\Mapper191.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\MMC3_family\Mapper192.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\MMC3_family\Mapper194.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\MMC3_family\Mapper196.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\MMC3_family\Mapper197.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\MMC3_family\Mapper205.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\MMC3_family\Mapper245.cs" />

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper196.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using BizHawk.Common;
+
+namespace BizHawk.Emulation.Cores.Nintendo.NES
+{
+	public class Mapper196 : MMC3Board_Base
+	{
+		// pirate crap
+		// behavior from fceumm
+		// standard MMC3, plus scrambled address lines to access the MMC3, and a bit of extra hardware
+		// adding a 32K prg banking mode
+
+		// config
+		int prg_bank_mask_32k;
+
+		// state
+		bool prgmode;
+		int prgreg;
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER196":
+					break;
+				default:
+					return false;
+			}
+
+			Cart.wram_size = 0;
+			prg_bank_mask_32k = Cart.prg_size / 32 - 1;
+			BaseSetup();
+			return true;
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.BeginSection("Mapper196");
+			ser.Sync("prgmode", ref prgmode);
+			ser.Sync("prgreg", ref prgreg);
+			ser.EndSection();
+		}
+
+		public override void WriteWRAM(int addr, byte value)
+		{
+			if (addr < 0x1000)
+			{
+				if (!prgmode)
+					Console.WriteLine("M196: 32K prg activated");
+				prgmode = true; // no way to turn this off once activated?
+				prgreg = value & 15 | value >> 4;
+				prgreg &= prg_bank_mask_32k;
+			}
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			// addresses are scrambled
+			if (addr >= 0x4000)
+			{
+				addr = (addr & 0xFFFE) | ((addr >> 2) & 1) | ((addr >> 3) & 1);
+			}
+			else
+			{
+				addr = (addr & 0xFFFE) | ((addr >> 2) & 1) | ((addr >> 3) & 1) | ((addr >> 1) & 1);
+			}
+			base.WritePRG(addr, value);
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			if (prgmode)
+			{
+				return ROM[addr | prgreg << 15];
+			}
+			else
+			{
+				return base.ReadPRG(addr);
+			}
+		}
+
+	}
+}