gb-research VS DMG-CPU-Inside

Gekkio's GB-CTR is a good reference of the SM83 (Gameboy CPU) with access pattern withM cycle accuracy. The GB-research repo by the same author also contains a lot of information.

If you want to go deeper, you can look at the reverse engineered schematic of most of the stuff except the CPU core in the DMG-CPU-Inside project. You could also consult the MetroBoy project, which builds on the previous project and aims to be accurate pretty much down to the logic gate level.

There's an ongoing project like this for the Gameboy that aims to build a logic block level description of the CPU and peripherals. There's also an emulator that's in very early stages (not sure if it's working at all yet). There's another edge accurate GB emulator which I don't believe is released yet, but should be work in progress.

The furthest I've seen publicly is the original Playstation ASICs. http://psxdev.ru/ [Russian Language]

Similar in time to the playstation ASICs (and similar design in sort of a soup of standard cells on a CMOS process), but at a gate count similar to Ken's fantastic work here on the 8086 is the work reversing the Gameboy SoC: https://github.com/furrtek/DMG-CPU-Inside

First I would try to deduce the timing from this gate-level simulation of the game boy, but the master branch was broken at the time, so I didn't manage to compile it. So, I tried deducing it from its underling reverse engineered schematics, but it would take too much time, if it even was possible.