Hey All,
For my emulator, I'm trying to separate VRC2 and VRC4 logic to the maximum extent possible. The VRC2 and VRC4 wiki page does not appear to provide heuristics for this. Based on the Nestopia source code for mapper 23, it appears that it is possible to determine between VRC2 and VRC4 before actually running the ROM (using ROM metadata instead). And it seems to determine the submapper number without relying on a submapper number being specified in a Nes2.0 header. But I can't figure out how it does this after a few hours of searching Nestopia source code.
Nestopia must have had this static determination before this issue with Wai Wai World mirroring was discovered and fixed based upon how little code change was required. Forum post mentioning Nestopia's static determination and other emulators' hacks.
Does anyone here know how to distinguish between mapper 23 submappers statically? I'm happy to use heuristics (like Nestopia presumably does), but I want to avoid full on hacks. I'll eventually implement NES2.0 headers too, but that's not relevant for most ROMs.
Thanks!
For my emulator, I'm trying to separate VRC2 and VRC4 logic to the maximum extent possible. The VRC2 and VRC4 wiki page does not appear to provide heuristics for this. Based on the Nestopia source code for mapper 23, it appears that it is possible to determine between VRC2 and VRC4 before actually running the ROM (using ROM metadata instead). And it seems to determine the submapper number without relying on a submapper number being specified in a Nes2.0 header. But I can't figure out how it does this after a few hours of searching Nestopia source code.
Nestopia must have had this static determination before this issue with Wai Wai World mirroring was discovered and fixed based upon how little code change was required. Forum post mentioning Nestopia's static determination and other emulators' hacks.
Does anyone here know how to distinguish between mapper 23 submappers statically? I'm happy to use heuristics (like Nestopia presumably does), but I want to avoid full on hacks. I'll eventually implement NES2.0 headers too, but that's not relevant for most ROMs.
Thanks!
Statistics: Posted by merehap — Sat Jan 27, 2024 10:25 pm — Replies 2 — Views 135