The last 2 days or so I've been looking at the PGM emulation, specifically DoDonPachi II. If you currently run DDP2 in UberMAME it will die with an error "Unhandled Coprocessor 13" or such. This is because the internal ROM for the DDP2 protection (ASIC27a) is currently undumped. I have written a small "replacement ROM" that goes in the file that would hold the dump. All it does is an infinite loop, so it's not actually handling any protection, it just allows the game to be (somewhat) played.
According to comments in the pgm.c code, the internal ROM for the ASIC27a should be dumpable, but it hasn't been yet. I've sent a question related to this to MAMEdev, so I'll be sure to let you all know about any updates to that. Aside from that, there were a few bugs in the PGM code which I have fixed (fixes some graphical glitches), but there are still some mysterious graphics glitches that I need to investigate further.
The game does run currently, and at a playable speed, but the game is not really playable. I say this because all bullet handling is performed by the ASIC27a, so the only bullets that actually work are the players. I'd presume this is because they offloaded all the work from 68k in the PGM to the ASIC27a on-cart, so the 68k could be used for everything else (since from what I've seen, DDP2 has a good lot of bullets, and there would be significant slowdown if everything was handled 68k side)
I'm probably dropping off of PGM for a bit soon, as my friend almost has all the stuff we need for our supergun, so I can begin hardware tests for Raiden II.
All comments or concerns welcome.
Temporary list of DDP2 Glitches and which graphic mode the error occurs in:
There occurs random garbage on the text-screen as soon as DDP2 loads, pgm_tx_tilemap.
Random column offsets that shouldn't exist (usually 1 or 2, offset by maybe 1/4th the screen-size.) in the Background layer, pgm_bg_tilemap
Random masking out and glitching of unknown graphics layers (!?)
I will probably find more. If you find any, please add to the list
The random masking and glitching appears in the sprite layer. This is very intriguing, as I am not sure what precisely could even cause this.
Haze has said that it is indeed dumpable, but it being dumped isn’t “high priority” right now, and other PGM games that need their ASIC27a’s dumped will probably be done first. So, just give it a while :)
How about that PGM. :P