[thrownawaysz]

mildy related but wasn't there an emulator (maybe not GB but NES or SNES?) which had a visual panel showing each CPU cycle step by step? afaik it was very slow but the 1000% accuracy was the goal not playability.

[andruc]

My guess is you're thinking of no$gmb, a very early Game Boy emulator:

https://gbatemp.net/threads/no-gmb-2-5-dos-full-version.6039...

I've got fond memories of using this to get a preview of Pokemon Gold before it was released in NA!

[thrownawaysz]

Found it

MetalNES, transistor level NES emulation https://github.com/iaddis/metalnes

While searching I also found a new one, VisualNES https://kaiokendev.github.io/nes/about

There is also one for GB https://github.com/aappleby/MetroBoy

[danparsonson]

See also Higan, formerly BSNES, which among other things is a cycle-accurate emulation of the SNES hardware and its enhancement chips (like the SuperFX used in StarFox/StarWing):

https://en.wikipedia.org/wiki/Higan_(emulator)

[andruc]

RIP Near

[hugeBirb]

I'm not sure if this is the one you are talking about but I remember seeing this a little while ago. https://mtmc.cs.montana.edu/

[thrownawaysz]

Found it

MetalNES, transistor level NES emulation https://github.com/iaddis/metalnes

While searching I also found a new one, VisualNES https://kaiokendev.github.io/nes/about

There is also one for GB https://github.com/aappleby/MetroBoy