trains

We recently added the Map::validCoords function. This should be used in a number of locations. Search the codebase for the constant 0x2FFF, 12287, 0x3000 or 12288 and if its a Map::Pos2 or Pos3 then it very likely should be using the validCoords function.

Likewise if its 384, 0x180, or 0x17F, 383 and if its a Map::TilePos2 then it should probably also be using the validCoords functi

Timer 4 is the 40 bit debug timer (as described under section 18.1.3). It's similar to Timers 1-3, albeit without as much "customization" options.

It should be fairly easy to implement:

• Modify the current timer device to use a internal u64 counter for time-keeping
• Create a "wrapper" device which masks masks out any timer registers unavailable on Timer 4
• Update the Ts7200Bus struc