SMS: Add "external cart ram" mapper for SG1000, fixes The Castle and Othello. Fortunately, both games are somewhat interesting and playable. SG1000 compat now 100% minus games requiring exotic peripherals

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

@@ -435,6 +435,7 @@
     <Compile Include="Consoles\Sega\Saturn\FilePiping.cs" />
     <Compile Include="Consoles\Sega\Saturn\LibYabause.cs" />
     <Compile Include="Consoles\Sega\Saturn\Yabause.cs" />
+    <Compile Include="Consoles\Sega\SMS\MemoryMap.ExtRam.cs" />
     <Compile Include="Consoles\Sega\SMS\MemoryMap.CodeMasters.cs" />
     <Compile Include="Consoles\Sega\SMS\MemoryMap.Sega.cs" />
     <Compile Include="Consoles\Sega\SMS\VDP.ModeTMS.cs" />
@@ -503,7 +504,6 @@
     <Compile Include="Consoles\Sega\Genesis\IO.cs" />
     <Compile Include="Consoles\Sega\Genesis\MemoryMap.68000.cs" />
     <Compile Include="Consoles\Sega\Genesis\MemoryMap.Z80.cs" />
-    <Compile Include="Consoles\Sega\SMS\BIOS.cs" />
     <Compile Include="Consoles\Sega\SMS\Input.cs" />
     <Compile Include="Consoles\Sega\SMS\SMS.cs" />
     <Compile Include="Consoles\Sega\SMS\VDP.cs" />

BizHawk.Emulation.Cores/Consoles/Sega/SMS/Compat.txt

@@ -7,7 +7,6 @@
   but don't really consider it super-high priority since it works correctly in PAL mode.
 
 * Desert Strike - you can enter the map screen but cannot leave.
-* Korean mapper needs to be implemented for SG-1000 games.
 
 Could probably stand to do another pass on SMS emulation after Genesis is working.
 
@@ -18,6 +17,4 @@ Could probably stand to do another pass on SMS emulation after Genesis is workin
 
 ======= SG-1000 compatibility checklist =======
 
-The Castle      Dies, mapper issue
-Othello         Doesnt boot
 Terebi Oekaki   Req Graphic Board peripheral

BizHawk.Emulation.Cores/Consoles/Sega/SMS/MemoryMap.ExtRam.cs

@@ -0,0 +1,41 @@
+namespace BizHawk.Emulation.Cores.Sega.MasterSystem
+{
+	public partial class SMS
+	{
+		byte[] ExtRam;
+		int ExtRamMask;
+
+		byte ReadMemoryExt(ushort address)
+		{
+			byte ret;
+
+			if (address < 0x8000)
+				ret = RomData[address];
+			else if (address < 0xC000)
+				ret = ExtRam[address & ExtRamMask];
+			else
+				ret = SystemRam[address & RamSizeMask];
+
+			CoreComm.MemoryCallbackSystem.CallRead(address);
+			return ret;
+		}
+
+		void WriteMemoryExt(ushort address, byte value)
+		{
+			if (address < 0xC000 && address >= 0x8000)
+				ExtRam[address & ExtRamMask] = value;
+			else if (address >= 0xC000)
+				SystemRam[address & RamSizeMask] = value;
+
+			CoreComm.MemoryCallbackSystem.CallWrite((uint)address);
+		}
+
+		void InitExt2kMapper(int size)
+		{
+			ExtRam = new byte[size];
+			ExtRamMask = size - 1;
+			Cpu.ReadMemory = ReadMemoryExt;
+			Cpu.WriteMemory = WriteMemoryExt;
+		}
+	}
+}

BizHawk.Emulation.Cores/Consoles/Sega/SMS/SMS.cs

@@ -130,10 +130,10 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 		public DisplayType DisplayType { get; set; }
 		public bool DeterministicEmulation { get { return true; } }
 
-		public SMS(CoreComm comm, GameInfo game, byte[] rom, object Settings, object SyncSettings)
+		public SMS(CoreComm comm, GameInfo game, byte[] rom, object settings, object syncSettings)
 		{
-			this.Settings = (SMSSettings)Settings ?? new SMSSettings();
+			Settings = (SMSSettings)settings ?? new SMSSettings();
-			this.SyncSettings = (SMSSyncSettings)SyncSettings ?? new SMSSyncSettings();
+			SyncSettings = (SMSSyncSettings)syncSettings ?? new SMSSyncSettings();
 
 			CoreComm = comm;
 			
@@ -151,7 +151,7 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 			CoreComm.VsyncDen = 1;
             
             if (game["Japan"]) Region = "Japan";
-            if (game.NotInDatabase || game["FM"] && this.SyncSettings.EnableFM && !IsGameGear)
+            if (game.NotInDatabase || game["FM"] && SyncSettings.EnableFM && !IsGameGear)
                 HasYM2413 = true;
 
             if (Controller == null)
@@ -171,12 +171,15 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
             ActiveSoundProvider = HasYM2413 ? (ISoundProvider)SoundMixer : PSG;
 
             SystemRam = new byte[0x2000];
-            if (game["CMMapper"] == false)
-                InitSegaMapper();
-            else
-                InitCodeMastersMapper();
 
-            if (this.Settings.ForceStereoSeparation && !IsGameGear)
+			if (game["CMMapper"])
+				InitCodeMastersMapper();
+			else if (game["ExtRam"])
+				InitExt2kMapper(int.Parse(game.OptionValue("ExtRam")));
+			else
+				InitSegaMapper();
+
+            if (Settings.ForceStereoSeparation && !IsGameGear)
             {
                 if (game["StereoByte"])
                 {
@@ -185,10 +188,10 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 				PSG.StereoPanning = ForceStereoByte;
             }
 
-            if (this.SyncSettings.AllowOverlock && game["OverclockSafe"])
+            if (SyncSettings.AllowOverlock && game["OverclockSafe"])
                 Vdp.IPeriod = 512;
 
-            if (this.Settings.SpriteLimit)
+            if (Settings.SpriteLimit)
                 Vdp.SpriteLimit = true;
 
 			if (game["3D"])
@@ -303,6 +306,7 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 			SystemRam.SaveAsHex(writer);
 			writer.WriteLine("Port01 {0:X2}", Port01);
 			writer.WriteLine("Port02 {0:X2}", Port02);
+			writer.WriteLine("Port3E {0:X2}", Port3E);
 			writer.WriteLine("Port3F {0:X2}", Port3F);
 			int SaveRamLen = Util.SaveRamBytesUsed(SaveRAM);
 			if (SaveRamLen > 0)
@@ -310,6 +314,11 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 				writer.Write("SaveRAM ");
 				SaveRAM.SaveAsHex(writer, SaveRamLen);
 			}
+			if (ExtRam != null)
+			{
+				writer.Write("ExtRAM ");
+				ExtRam.SaveAsHex(writer, ExtRam.Length);
+			}
 			if (HasYM2413)
 			{
 				writer.Write("FMRegs ");
@@ -345,6 +354,11 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 					for (int i = 0; i < SaveRAM.Length; i++) SaveRAM[i] = 0;
 					SaveRAM.ReadFromHex(args[1]);
 				}
+				else if (args[0] == "ExtRAM")
+				{
+					for (int i = 0; i < ExtRam.Length; i++) ExtRam[i] = 0;
+					ExtRam.ReadFromHex(args[1]);
+				}
 				else if (args[0] == "FMRegs")
 				{
 					byte[] regs = new byte[YM2413.opll.reg.Length];
@@ -356,6 +370,8 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 					Port01 = byte.Parse(args[1], NumberStyles.HexNumber);
 				else if (args[0] == "Port02")
 					Port02 = byte.Parse(args[1], NumberStyles.HexNumber);
+				else if (args[0] == "Port3E")
+					Port3E = byte.Parse(args[1], NumberStyles.HexNumber);
 				else if (args[0] == "Port3F")
 					Port3F = byte.Parse(args[1], NumberStyles.HexNumber);
 				else if (args[0] == "[Z80]")
@@ -371,7 +387,10 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 
 		public byte[] SaveStateBinary()
 		{
-			var buf = new byte[24806 + 1 + 16384 + 16384];
+			int buflen = 24808 + 16384 + 16384;
+			if (ExtRam != null)
+				buflen += ExtRam.Length;
+			var buf = new byte[buflen];
 			var stream = new MemoryStream(buf);
 			var writer = new BinaryWriter(stream);
 			SaveStateBinary(writer);
@@ -399,7 +418,10 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 			writer.Write(SaveRAM);
 			writer.Write(Port01);
 			writer.Write(Port02);
+			writer.Write(Port3E);
 			writer.Write(Port3F);
+			if (ExtRam != null)
+				writer.Write(ExtRam);
 			writer.Write(YM2413.opll.reg);
 		}
 
@@ -419,7 +441,10 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 			reader.Read(SaveRAM, 0, SaveRAM.Length);
 			Port01 = reader.ReadByte();
 			Port02 = reader.ReadByte();
+			Port3E = reader.ReadByte();
 			Port3F = reader.ReadByte();
+			if (ExtRam != null)
+				reader.Read(ExtRam, 0, ExtRam.Length);
 			if (HasYM2413)
 			{
 				byte[] regs = new byte[YM2413.opll.reg.Length];

output/gamedb/gamedb_sega_8bit.txt

@@ -1914,7 +1914,7 @@ D8A87095	 	Bank Panic	SG
 EA0F2691	 	Bomb Jack	SG	
 0B4BCA74	 	Borderline	SG
 BE7ED0EB	 	C_So! (JP)	SG
-092F29D6	 	The Castle	SG
+092F29D6	 	The Castle	SG		ExtRam=8192
 D37BDA49	 	Chack'n Pop	SG
 5970A12B	 	Champion Baseball	SG
 62B21E31	 	Champion Billiards	SG
@@ -1960,7 +1960,8 @@ BA09A0FD	 	Hyper Sports (Konami no)	SG
 3B912408	 	Ninja Princess	SG
 09196FC5	 	N-Sub [1988]	SG
 F4F78B76	 	Orguss	SG
-AF4F14BC	 	Othello (JP)	SG
+AF4F14BC	 	Othello (JP)	SG		ExtRam=2048
+1D1A0CA3		Othello (TW)	SG		ExtRam=2048
 30C52E5E	 	Pacar	SG
 326587E1	 	Pachinko (JP)	SG
 FD7CB50A	 	Pachinko II	SG