NES: support CAMERICA-GAMEGENIE (partially). you can't actually use it; it's mostly for documentation purposes.

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

@@ -243,6 +243,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\BxROM.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Camerica.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\FS304.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\GameGenie.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper028.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\CNROM.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\CPROM.cs">

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/GameGenie.cs

@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using BizHawk.Common;
+
+namespace BizHawk.Emulation.Cores.Nintendo.NES
+{
+	// this is an internal testing thing, not really for using
+
+	public class GameGenie : NES.NESBoardBase
+	{
+		static byte[] NameTables = new byte[256];
+
+		static GameGenie()
+		{
+			for (int addr = 0; addr < 256; addr++)
+			{
+				byte d = 0;
+				if (addr.Bit(2))
+				{
+					if (addr.Bit(4)) d |= 16;
+					if (addr.Bit(5)) d |= 1;
+				}
+				else
+				{
+					if (addr.Bit(6)) d |= 16;
+					if (addr.Bit(7)) d |= 1;
+				}
+				d |= (byte)(d << 1);
+				d |= (byte)(d << 2);
+				NameTables[addr] = d;
+			}
+		}
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "CAMERICA-GAMEGENIE":
+					break;
+				case "UNIF_CAMERICA-GAMEGENIE":
+					break;
+				default:
+					return false;
+			}
+			AssertChr(0); AssertPrg(4);
+			Cart.wram_size = 0;
+			Cart.vram_size = 0;
+
+			SetMirroring(0, 0, 0, 0);
+
+			return true;
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			if (addr < 0x4000)
+				return NES.DB;
+			else
+				return ROM[addr & 0xfff];
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr >= 0x2000)
+				return base.ReadPPU(addr);
+			else
+				return NameTables[addr & 0xff];
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			NES.LogLine("{0:x4}<={1:x2}", addr + 0x8000, value);
+		}
+	}
+}

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/NROM.cs

@@ -68,10 +68,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 					AssertChr(8); AssertVram(0); AssertWram(0);
 					break;
 
-				case "CAMERICA-GAMEGENIE":
-					// if you really want to emulate a game genie, it isn't NROM
-					throw new Exception("Game Genie Support NYI");
-
 				case "HVC-FAMILYBASIC":
 					// we don't emulate the controller, so this won't work
 					AssertPrg(32); AssertChr(8); AssertWram(2, 4);