Support for larger controller paks

[Jhynjhiruu]

Libultra's code for dealing with controller paks has functionality for dealing with paks larger than 32KiB in size, using banking. While no official Nintendo paks larger than 32KiB have been confirmed to exist (there's suspicion that a small run of 64KiB paks were made, and the Libultra documentation mentions both 32KiB and 64KiB paks existing), Datel made at least two types of larger controller paks, which are (nearly) fully compatible with all N64 games that use controller pak saves.

mpkedit, wonderful though it is, can only deal with 32KiB paks. I've found myself needing to create larger paks, and I'd love to do it using mpkedit, but I can't puzzle through how the JavaScript works to add the functionality myself. I'd be very happy to collaborate on adding support, since I know how the filesystem should work for larger paks and I've written code to read them.

For testing, there's currently an open PR adding support for larger paks to ares, the multi-system emulator, and I've forked Polprzewodnikowy's PicoJoybus project to support emulating larger paks on hardware.

[bryc]

Yeah it's something I've been considering - I'm basically waiting on emulators and flashcarts for this. Without an actual source that can load and save real high-capacity save dumps (emu or flashcart), the priority is kinda low. You say you need them; is there now a way for Datel owners to even dump and reflash the entire capacity on flashcarts? I'm not sure what you mean by emulation, an official Nintendo pak can somehow bankswitch via sd card now?

I've got a pretty good wip C-Pak library in C that supports robust error detection/repair operations that might make a good candidate for inclusion in libdragon (https://github.com/bryc/CPak-Lib-Sim/blob/main/cpak.c). The plan is to bring it back to MPKEdit once it's done. Problem is it's hardcoded to operate on 32 KiB dumps atm. I wasn't sure if the complexity of supporting variable sizes would be worth it. But yeah, 100% open to supporting higher capacities if ares actually gets it working for people to use.

PS. If you got a bunch of higher capacity save dumps on hand, send them my way.. at least something to test a parser with.