Nestopia cheat code bug, or am I doin' it rongz?

This is an archive of a topic from NESdev BBS, taken in mid-October 2019 before a server upgrade.
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Nestopia cheat code bug, or am I doin' it rongz?
by on (#79153)
This morning I was working on narrowing down a cheat code for Super Bat Puncher (hee hee hee :D :D :D). Because Nestopia's "cheat helper" (for lack of better term) sucks, I decided to use FCEUXD SP's RAM Filter, which worked wonderfully. Sure enough I was able to find what I wanted: messing around with ZP variables $D0 to $D9. Entering these in the FCEUXD SP cheat section worked fine, voila.

I then took the same address and value and brought it over into Nestopia as a permanent cheat code (using a 16-bit address, e.g. $00D0)... nothing. Even re-examining the RAM contents inside of the cheat code editor confirmed that the address/value I chose was literally being ignored. *blink blink*

Then it hit me: maybe Nestopia is doing something weird with its address/value masking (overrides), where it's effectively limiting the addressing range to $8000-FFFF (PRG space)? This would (for lack of better word) "mimic", in a way, how the Game Genie works.

I haven't looked at the Nestopia source code yet -- I've done so many times so that's not a limiting factor, but it takes a lot of time -- and I figured I'd ask here first.

Has anyone had success using Nestopia's cheat system to overwrite values in ZP?