add a new field to IEmulator: bool BinarySaveStatesPreferred { get; }. a core should set it to true to indicate that it would prefer to save and load binary savestates (but both types must be supported). set to true on 7800, gb, dgb, gba, n64, snes, saturn cores, as they all create text savestates that are simply dumps of the binary savestate. for the moment, frontend does nothing with this new information.

BizHawk.Emulation/Computers/Commodore64/C64.cs

@@ -140,6 +140,8 @@ namespace BizHawk.Emulation.Computers.Commodore64
 			return ms.ToArray();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		private void SetupMemoryDomains()
 		{
 			// chips must be initialized before this code runs!

BizHawk.Emulation/Consoles/Atari/2600/Atari2600.cs

@@ -99,6 +99,8 @@ namespace BizHawk
 			return ms.ToArray();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		private readonly IList<MemoryDomain> memoryDomains;
 		public IList<MemoryDomain> MemoryDomains { get { return memoryDomains; } }
 		public MemoryDomain MainMemory { get { return memoryDomains[0]; } }

BizHawk.Emulation/Consoles/Atari/7800/Atari7800.cs

@@ -117,6 +117,9 @@ namespace BizHawk.Emulation
 			bw.Flush();
 			return ms.ToArray();
 		}
+
+		public bool BinarySaveStatesPreferred { get { return true; } }
+
 		void SyncState(Serializer ser)
 		{
 			byte[] core = null;

BizHawk.Emulation/Consoles/Calculator/TI83.cs

@@ -588,6 +588,8 @@ namespace BizHawk.Emulation.Consoles.Calculator
 			return new byte[0];
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		public string SystemId { get { return "TI83"; } }
 
 		private IList<MemoryDomain> memoryDomains;

BizHawk.Emulation/Consoles/Coleco/ColecoVision.cs

@@ -204,6 +204,8 @@ namespace BizHawk.Emulation.Consoles.Coleco
 			return buf;
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		public void SaveStateBinary(BinaryWriter writer)
 		{
 			Cpu.SaveStateBinary(writer);

BizHawk.Emulation/Consoles/Intellivision/Intellivision.cs

@@ -179,6 +179,8 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 			return new byte[0];
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		public CoreComm CoreComm { get; private set; }
 
 		public IList<MemoryDomain> MemoryDomains

BizHawk.Emulation/Consoles/Nintendo/GBA/Meteor.cs

@@ -176,6 +176,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo.GBA
 			return ms.ToArray();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return true; } }
+
 		#endregion
 
 		public CoreComm CoreComm { get; private set; }

BizHawk.Emulation/Consoles/Nintendo/Gameboy/Gambatte.cs

@@ -405,6 +405,8 @@ namespace BizHawk.Emulation.Consoles.GB
 			return ms.ToArray();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return true; } }
+
 		#endregion
 
 		#region memorycallback

BizHawk.Emulation/Consoles/Nintendo/Gameboy/GambatteLink.cs

@@ -284,6 +284,8 @@ namespace BizHawk.Emulation.Consoles.GB
 			return ms.ToArray();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return true; } }
+
 		#endregion
 
 		public CoreComm CoreComm { get; private set; }

BizHawk.Emulation/Consoles/Nintendo/N64/N64.cs

@@ -176,6 +176,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo.N64
 			return ms.ToArray();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return true; } }
+
 		public IList<MemoryDomain> MemoryDomains { get; private set; }
 		public MemoryDomain MainMemory { get; private set; }
 

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

@@ -849,6 +849,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			bw.Flush();
 			return ms.ToArray();
 		}
+
+		public bool BinarySaveStatesPreferred { get { return false; } }
 	}
 }
 

BizHawk.Emulation/Consoles/Nintendo/SNES/LibsnesCore.cs

@@ -787,6 +787,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo.SNES
 			return ms.ToArray();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return true; } }
+
 		/// <summary>
 		/// handle the unmanaged part of loadstating
 		/// </summary>

BizHawk.Emulation/Consoles/PC Engine/PCEngine.cs

@@ -535,6 +535,8 @@ namespace BizHawk.Emulation.Consoles.TurboGrafx
 			return buf;
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		void SetupMemoryDomains()
 		{
 			var domains = new List<MemoryDomain>(10);

BizHawk.Emulation/Consoles/PSX/Octoshock.cs

@@ -252,6 +252,7 @@ namespace BizHawk.Emulation.Consoles.PSX
 		public void SaveStateBinary(BinaryWriter writer) { }
 		public void LoadStateBinary(BinaryReader reader) { }
 		public byte[] SaveStateBinary() { return new byte[1]; }
+		public bool BinarySaveStatesPreferred { get { return false; } }
 		public int[] GetVideoBuffer() { return frameBuffer; }
 		public int VirtualWidth { get; private set; }
 		public int BufferWidth { get; private set; }

BizHawk.Emulation/Consoles/Sega/Genesis/Genesis.cs

@@ -408,6 +408,8 @@ namespace BizHawk.Emulation.Consoles.Sega
             return buf;
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		IList<MemoryDomain> memoryDomains;
 
 		void SetupMemoryDomains()

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

@@ -315,6 +315,8 @@ namespace BizHawk.Emulation.Consoles.Sega
 			return buf;
 		}
 
+		public bool BinarySaveStatesPreferred { get { return false; } }
+
 		public void SaveStateBinary(BinaryWriter writer)
 		{
 			Cpu.SaveStateBinary(writer);

BizHawk.Emulation/Consoles/Sega/Saturn/Yabause.cs

@@ -310,6 +310,8 @@ namespace BizHawk.Emulation.Consoles.Sega.Saturn
 			Frame = reader.ReadInt32();
 		}
 
+		public bool BinarySaveStatesPreferred { get { return true; } }
+
 		public byte[] SaveStateBinary()
 		{
 			MemoryStream ms = new MemoryStream();

BizHawk.Emulation/Interfaces/Base Implementations/NullEmulator.cs

@@ -54,6 +54,7 @@ namespace BizHawk
 		public void SaveStateBinary(BinaryWriter writer) { }
 		public void LoadStateBinary(BinaryReader reader) { }
 		public byte[] SaveStateBinary() { return new byte[1]; }
+		public bool BinarySaveStatesPreferred { get { return false; } }
 		public int[] GetVideoBuffer() { return frameBuffer; }
         public int VirtualWidth { get { return 256; } }
         public int BufferWidth { get { return 256; } }

BizHawk.Emulation/Interfaces/IEmulator.cs

@@ -62,6 +62,11 @@ namespace BizHawk
 		void LoadStateBinary(BinaryReader reader);
 		byte[] SaveStateBinary();
 
+		/// <summary>
+		/// true if the core would rather give a binary savestate than a text one.  both must function regardless
+		/// </summary>
+		bool BinarySaveStatesPreferred { get; }
+
 		/// <summary>
 		/// the corecomm module in use by this core.
 		/// </summary>