cps2.cpp: Added TOURNAMENT board communication simulation.

[cuavas]

Thanks to Darksoft for tracing the board, and @originalgrego for producing a proof of concept implementation.

To use this, enable communication in the Machine Configuration menu for four instances of ssf2tb or a clone, and then daisy-chain them using the various comm_* options. The comm_remotehost option for the head of the daisy chain must be empty. For example, to run them all on one machine:

• mame ssf2tb -comm_localhost 0.0.0.0 -comm_localport 1234 -comm_remotehost ""
• mame ssf2tb -comm_localhost 0.0.0.0 -comm_localport 1235 -comm_remotehost 127.0.0.1 -comm_remoteport 1234
• mame ssf2tb -comm_localhost 0.0.0.0 -comm_localport 1236 -comm_remotehost 127.0.0.1 -comm_remoteport 1235
• mame ssf2tb -comm_localhost "" -comm_remotehost 127.0.0.1 -comm_remoteport 1236

The TOURNAMENT board apparently can generate interrupts, but the game doesn’t seem to mind if it doesn’t – it still polls the USART. This is all simulated at a very high level due to the way MAME only synchronises with the wall clock once per frame – on a typical PC, the main thread is sleeping over 90% of the time when running a CPS2 game. Trying to do it more realistically would require major changes to MAME’s event loop.

The games will lose sync pretty quickly if they aren’t running at the same speed (e.g. if you try to fast-forward one of them). I’ve had it lose sync once with normal play, but it seems to work fairly well most of the time.

[cuavas]

Oh, I also untangled the CPS-2 class from the CPS-1 files while I was at it.

[cuavas]