Wednesday, 11 December 2013

Coins and housekeeping

Last night I did a few tidy-ups; reviewed (again) any missing functionality in the execution path thus far and found a small routine that 'fixes' the moving ladders on the 2nd (cement pie) level. Still a few sundry items and sprites which I'm yet to port, but they don't seem too important atm. And for some reason, the ladder-tops have appeared again on the title screen (although the transition from demo mode to title screen is a hack atm, so I'm not too fussed).

I also decided to code the coin-up logic, and found that the Neo Geo does things very differently to other arcade games. All the title, demo, credit and start functions are handled by the BIOS. I had to fill in a few missing vector functions in the cartridge header, and also had to set the USER_MODE variable in the system work area before I could get the coin-up function working, but now I can add a credit (not sure yet how this will translate to the non-MVS platforms). That's still WIP so you can't actually start a game yet.

I also took a quick look through the rest of the code, in particular the game-play loop. It all looks fairly straight-forward, and I should be able to get Mario moving about without having to worry about porting the rest of the game logic. There's quite a bit of crank-the-handle type porting to be done, which might be a little tedious but shouldn't throw up any surprises and will hopefully be straightforward to test as I go.

 But first, I'd like to be able to start a game.

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