Irem M107 HW, a driver that indeed didn’t received much love in his life. The driver was a complete mess, with completely broken World PK Soccer, Dream Soccer ’94 with huge slowdowns and Fire Barrel … well, it was marked as working but imho it wasn’t really working, with that layer covering half the screen and completely missing sound, effectively making it a painful experience to play. After some study at the code, I’ve realized that the driver was continously triggering an unmapped line from the main CPU, directly correlated to some sound response r/w. Easy fix, that’s a reset line directly connected to the sound CPU.

Then the graphics. After some study at the code me and Haze realized that current rowscroll handling was entirely wrong, since that rowscroll is enabled thru a completely different bit (used by World PK Soccer gameplay) … we studied some videos of the real PCB floating around the net and realized it was actually enabling row select, a kind of effect also used in this game for stretching the tilemap in the vertical axis (effectively doing some pseudo zooming).

We have still to do rowscroll effects for Fire Barrel (used for the sea on level 2 and the canyon on level 6) and several sprite fixes, but I can safely assume that Fire Barrel is a lot more playable now that it ever was. My preliminary hook-up already makes World PK Soccer to have better gfxs than before, but it’s still not 100% right for Fire Barrel …



Source: mamedev.emulab.it/kale/