Make a zombie board for m34 that attempts to support bad dumps of both bxrom and ave-nina

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

@@ -511,6 +511,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper015.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper029.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper030.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\Mapper034.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper036.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper038.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper040.cs" />

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

@@ -31,9 +31,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				case "NES-BNROM": //Deadly Towers (U)
 					AssertPrg(128); AssertChr(0); AssertWram(0); AssertVram(8);
 					break;
-				case "MAPPER034": // 3-D Battles of World Runner, The (U) [b5].nes
+
-					// TODO: No idea what to assert here
-					break;
 				default:
 					return false;
 			}

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/Mapper034.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Cores.Nintendo.NES
+{
+	public sealed class Mapper034 : NES.NESBoardBase
+	{
+		// zombie board that tries to handle both bxrom and ave-nina at once
+
+		//configuration
+		int prg_bank_mask_32k, chr_bank_mask_4k;
+
+		//state
+		int[] chr = new int[2];
+		int prg;
+
+
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER034": // 3-D Battles of World Runner, The (U) [b5].nes
+					// TODO: No idea what to assert here
+					break;
+				default:
+					return false;
+			}
+
+			Cart.wram_size = 8;
+			prg_bank_mask_32k = Cart.prg_size / 32 - 1;
+			chr_bank_mask_4k = Cart.chr_size / 4 - 1;
+
+			SetMirrorType(Cart.pad_h, Cart.pad_v);
+			chr[1] = 1;
+
+			return true;
+		}
+
+		public override byte ReadPPU(int addr)
+		{
+			if (addr < 0x2000)
+				return (VROM ?? VRAM)[addr & 0xfff | chr[addr >> 12] << 12];
+			else
+				return base.ReadPPU(addr);
+		}
+
+		public override byte ReadPRG(int addr)
+		{
+			return ROM[addr | prg << 15];
+		}
+
+		public override void WritePRG(int addr, byte value)
+		{
+			prg = value & prg_bank_mask_32k;
+		}
+
+		public override void WriteWRAM(int addr, byte value)
+		{
+			switch (addr)
+			{
+				case 0x1ffd:
+					prg = value & prg_bank_mask_32k;
+					break;
+				case 0x1ffe:
+					chr[0] = value & chr_bank_mask_4k;
+					break;
+				case 0x1fff:
+					chr[1] = value & chr_bank_mask_4k;
+					break;
+				default:
+					// on NINA, the regs sit on top of WRAM
+					base.WriteWRAM(addr, value);
+					break;
+			}
+		}
+	}
+}