Cheats implemented in the TI83 core, show messagebox on Cheat enable failure

BizHawk.Emulation/Consoles/Calculator/TI83.cs

@@ -25,17 +25,25 @@ namespace BizHawk.Emulation.Consoles.Calculator
 		uint disp_x, disp_y;
 		int m_LinkOutput, m_LinkState;
 		bool m_CursorMoved;
+
+		MemoryDomain.FreezeData[] sysbus_freeze = new MemoryDomain.FreezeData[0x10000];
 		//-------
 
 		public byte ReadMemory(ushort addr)
 		{
+			byte ret;
 			int romPage = romPageLow3Bits | (romPageHighBit << 3);
 			//Console.WriteLine("read memory: {0:X4}", addr);
 			if (addr < 0x4000)
-				return rom[addr]; //ROM zero-page
+				ret =  rom[addr]; //ROM zero-page
 			else if (addr < 0x8000)
-				return rom[romPage * 0x4000 + addr - 0x4000]; //other rom page
-			else return ram[addr - 0x8000];
+				ret = rom[romPage * 0x4000 + addr - 0x4000]; //other rom page
+			else ret = ram[addr - 0x8000];
+
+			//apply freeze
+			if (sysbus_freeze[addr].IsFrozen) ret = sysbus_freeze[addr].value;
+
+			return ret;
 		}
 
 		public void WriteMemory(ushort addr, byte value)
@@ -581,6 +589,9 @@ namespace BizHawk.Emulation.Consoles.Calculator
 				(addr, value) => ram[addr & RamSizeMask] = value);
 			domains.Add(MainMemoryDomain);
 			memoryDomains = domains.AsReadOnly();
+
+			MainMemoryDomain.GetFreeze = addr => sysbus_freeze[addr];
+			MainMemoryDomain.SetFreeze = (addr, value) => sysbus_freeze[addr] = value;
 		}
 
 		public IList<MemoryDomain> MemoryDomains { get { return memoryDomains; } }

BizHawk.MultiClient/tools/Cheats.cs

@@ -161,7 +161,6 @@ namespace BizHawk.MultiClient
 				case "SG":
 				case "GG":
 				case "PCE":
-				case "TI83":
 					AddCheatGroup.Enabled = false;
 					CheatListView.Enabled = false;
 					MessageLabel.Text = Global.Emulator.SystemId + " not supported.";
@@ -645,7 +644,10 @@ namespace BizHawk.MultiClient
 						else
 							c.Enable();
 					}
-					catch { }
+					catch
+					{
+						NotSupportedError();
+					}
 
 					y = s.IndexOf('\t') + 1;
 					s = s.Substring(y, s.Length - y); //Name
@@ -668,6 +670,12 @@ namespace BizHawk.MultiClient
 			return true; //TODO
 		}
 
+		private void NotSupportedError()
+		{
+			MessageBox.Show("Unable to enable cheat for this platform, cheats are not supported for " + Global.Emulator.SystemId, "Cheat error",
+							MessageBoxButtons.OK, MessageBoxIcon.Error);
+		}
+
 		private void OpenCheatFile()
 		{
 			var file = GetFileFromUser();
@@ -729,8 +737,12 @@ namespace BizHawk.MultiClient
 			c.address = int.Parse(AddressBox.Text, NumberStyles.HexNumber); //TODO: validation
 			c.value = (byte)(int.Parse(ValueBox.Text, NumberStyles.HexNumber));
 			c.domain = Global.Emulator.MemoryDomains[DomainComboBox.SelectedIndex];
-			try { c.Enable(); }
-			catch { }
+			try { 
+				c.Enable();
+			} 
+			catch {
+				NotSupportedError();
+			}
 			return c;
 		}
 
@@ -841,8 +853,14 @@ namespace BizHawk.MultiClient
 						cheatList[indexes[x]].Disable();
 					else
 					{
-						try { cheatList[indexes[x]].Enable(); }
-						catch { }
+						try
+						{
+							cheatList[indexes[x]].Enable();
+						}
+						catch
+						{
+							NotSupportedError();
+						}
 					}
 				}
 				CheatListView.Refresh();