most emulators emulate instruction set, maybe little bit the of behavior; (that is why we dont get accurate results on all emulators)

but what if we take a die and simulate the compete architecture?, well this video is about simulating the 6502 architecture.

https://www.youtube.com/watch?v=fWqBmmPQP40

Cycle accurate hardware emulators already exist of course.

They either aren't cheap, or aren't for sale, so anything that challenges that is a good thing IMO.

im not sure about software emulators, but i remember in 2000s someone showed me cool stuff at his place; he had an ICE (in-circuit emulator) for a japanese microprocessor, it was cool to see what happen after every cycle ~ 1 nano second at a time. (it also shows current address + bytes)

i wish if we have ICE for modern x86 chips, that would open a new era of reverse engineering that includes CPU, firmware and ram.

only those tech. companies who are involved in nano-tech. can build these stuff, and i bet most of these companies do reverse engineer each other's products.

ICEs in modern chips are often already embedded inside. ARM has a module that the makers can optionally include in the die (most of them do include it) and then everyone can access the system. You still need an external interface, often using JTAG, and then you can single step at the hardware level.

However many of the commercial x86 mobos you can buy cheaply often omit the connections to the JTAG interface, and/or the chip itself is packaged to not externally expose the JTAG. So chances are you will need an engineering sample to be able to make use of the embedded ICE.