programmer questions


Galford's Armourer
Dec 30, 2009
I have a project running (see sig) that uses the memory card and I would personally like to run on an MVS so I have two questions. I'll try to keep it brief:

#1: how much of the 4MB memory card space can the neo actually address? I am pretty sure the BIOS imposes a (possibly arbitrary) limit of 16KB on 8bit cards and 32KB on 16bit cards when I poked around it before. If it can go any higher with direct access, it'd probably help out.

#2: are there any major caveats with running homebrew code on an MVS. In particular, anything that WON'T show up in an emulator but will definitely show up on real hardware. I do not have the means to test on real hardware as of now, otherwise I'd just homebrew a few tests and figure it out myself.

Slightly offtopic: What is "SNK ROM " that the BIOS tries to look for in the card slot? Anyone who RE'd the BIOS will recognize that, it's some sort of 16bit ROM card(???) but nothing of the sort was ever released. Not publicly, anyway. There's also "SAMURAI3 AI CARD" but I'm sure that was just used by the developers to make debugging easier, nothing interesting.

Anyway, I'm sure there's a bunch of homebrewers with such a large community here so if any of you have anything to share I'd appreciate it. This stuff is so extensively documented for the Nintendo systems but not so much for neo hardware.