MiSTer FPGA Forum

The C64 core offers an option to allow C128-like 2MHz border acceleration...would it be possible to also enable an additional 64K of RAM to allow Ultima V music to work on the C64? (Yes, I'm aware the EasyFlash conversion does...I mean the native disk version.)

I looked it up, and the real thing needs a C128, so it's probable that the Flash conversion has patched the game a fair bit. Apparently the musical version won't even start in 64 mode, it requires a 128, and either a clean boot or the BOOT command. It doesn't sound like just adding another 64K to the C64 emulator is likely to work.

Presumably, someone could also have patched the disks, in which case the music might work with the REU, but that's pure hypothesis on my part. It definitely wouldn't be the original game. If you want the real code from the original disk images, it sounds like you'd have to wait for the C128 core to be finished.

One caveat: I'm only an intermediate C64 user. Pay attention to anyone that contradicts me.

As far as I know, there weren't any separate C128 disks, just one set that somehow detected a C128 when booted on one (but worked perfectly normally, with sound effects but no music, on the C64).

From discussions on other forums, it sounds like the 128-mode program launches with BOOT or by autobooting; probably the fact that the specific autoboot program was running told the program it was a C128. I didn't see any details, but it might just set a flag or something, and launch the main binary.

It seems likely that the binary would need to be patched to support any kind of C64-mode RAM expansion, since it probably expects to be running in C128 mode. I don't know the technical internals, but it seems unlikely that just providing extra RAM would be enough, it would also require modifications to the program.

If there's an EasyFlash version that already does what you want, then someone already did that heavy lifting. Might as well take advantage.

I'm going to try loading it on a 128 in C64 mode to see what it does...never actually tried. If no music, no point. Games that take advantage of border speedups like Uridium Plus can do that even when booted in that matter (I'm pretty sure - it's been quite a while since I did this on bare iron).

https://csdb.dk/release/?id=227816

Go here and get the latest that plays music etc on the C64

He mentioned he knew about the EasyFlash version, but was trying to run from original disks with music on the C64 core. That doesn't seem likely to work.

Original Disks Won't Work

Yes, we had kinda figured that out already.

Alright - yeah, results are as expected. Uridium Plus can detect 2MHz mode availability from C64 side (in fact, that's the only way the game will work), but U5 music only works if BOOTed in C128 mode (all tested on VICE). Bummer.

Thanks all!

Myself, I probably wouldn't be a purist, and would run the EasyFlash version. You're in the same situation you would be with a real 64; the Mister is being accurate, and you're doing what real 64 users would do.

That way, you don't have to wait for a C128 core to be finished.

LOL I'm still working to try to help beat the C128 core into shape, but some of the issues completely mystify me.