nes mapper 143 : magic math, dancing blocks. dancing blocks refuses to run due to core problem? see comments...

BizHawk.Emulation/BizHawk.Emulation.csproj

@@ -168,6 +168,7 @@
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper116.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper120.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper132.cs" />
+    <Compile Include="Consoles\Nintendo\NES\Boards\Mapper143.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper156.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper164.cs" />
     <Compile Include="Consoles\Nintendo\NES\Boards\Mapper168.cs" />

BizHawk.Emulation/Consoles/Nintendo/NES/Boards/Mapper143.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Consoles.Nintendo
+{
+	// sachen
+	// NROM plus random copy protection circuit
+
+	// dancing blocks refuses to run; see comments below	
+	public class Mapper143 : NES.NESBoardBase
+	{
+		public override bool Configure(NES.EDetectionOrigin origin)
+		{
+			switch (Cart.board_type)
+			{
+				case "MAPPER143":
+				case "UNIF_UNL-SA-NROM":
+					break;
+				default:
+					return false;
+			}
+			AssertPrg(32);
+			AssertChr(8);
+			SetMirrorType(Cart.pad_h, Cart.pad_v);
+			return true;
+		}
+
+		public override byte ReadEXP(int addr)
+		{
+			if ((addr & 0x100) != 0)
+				return (byte)(NES.DB & 0xc0 | ~addr & 0x3f);
+			else
+				return NES.DB;
+		}
+
+		/* if this awful hack is uncommented, dancing blocks runs
+		   it initializes ram to a different pseudo-random pattern
+
+		bool first = true;
+		public override void ClockPPU()
+		{
+			if (first)
+			{
+				first = false;
+				for (int i = 0; i < 0x800; i++)
+					NES.WriteMemory((ushort)i, (i & 4) != 0 ? (byte)0x7f : (byte)0x00);
+			}
+		}
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.Sync("first", ref first);
+		}
+		*/
+	}
+}