Atari - slight fix to support the F4 mapper

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

@@ -113,7 +113,7 @@ namespace BizHawk
 				case "CV": mapper = new mCV(); break;
 				case "F8": mapper = new mF8(); break;
 				case "F6": mapper = new mF6(); break;
-				case "F4": mapper = new mF4(); break;
+				case "F4": case "F4SC": mapper = new mF4(); break;
 				case "FE": mapper = new mFE(); break;
 				case "E0": mapper = new mE0(); break;
 				case "3F": mapper = new m3F(); break;

BizHawk.Emulation/Consoles/Atari/2600/Mappers/mE7.cs

@@ -55,7 +55,8 @@ namespace BizHawk.Emulation.Consoles.Atari._2600
 			}
 			else if (addr < 0x1800) return core.rom[toggle * 2 * 1024 + (addr & 0x7FF)];
 			else if (addr < 0x1A00) return rambank1[toggle * 256 + (addr & 0x255)];
-			else if (addr < 0x2000) return core.rom[14848 + (addr & 0x5FF)]; //Fixed to last 1.5K
+			else if (addr < 0x2000) 
+				return core.rom[14848 + (addr & 0x5FF)]; //Fixed to last 1.5K
 			else return base.ReadMemory(addr);
 		}
 		public override void WriteMemory(ushort addr, byte value)

BizHawk.Emulation/Consoles/Atari/2600/Mappers/mF0.cs

@@ -47,8 +47,7 @@ namespace BizHawk.Emulation.Consoles.Atari._2600
 		void Increment()
 		{
 			bank++;
-			if (bank > 15) 
-				bank = 0;
+			bank &= 0x0F;
 		}
 	}
 }