gen: allow word-reads to query Z80 bus status. now thunder force 3 boots.

BizHawk.Emulation/Consoles/Sega/Genesis/MemoryMap.68000.cs

@@ -59,6 +59,12 @@ namespace BizHawk.Emulation.Consoles.Sega
             if (address >= 0xA10000 && address <= 0xA1001F)
                 return (sbyte)ReadIO(address);
 
+            if (address == 0xA11100) // Z80 BUS status
+            {
+                // TODO: note, its possible that something is supposed to be on the MSB (crap from the bus, ie, the next instruction)
+                return (short)(M68000HasZ80Bus && Z80Reset == false ? 0 : 1);
+            }
+
             Console.WriteLine("UNHANDLED READW {0:X6}", address);
             return 0x7DCD;
         }