At this point you can write the circuitry in SPICE and the chips in Verilog and simulate the whole old console clock by clock down to the transistor level and still get a playable game out of it
Of course this is only viable until say… before the 3D era or so
If you go old enough, the problem often falls in the imperfections of the tech. When you simulate the whole console perfectly, you are idealizing a system that was far from perfect, and you might miss real features that depended on that.
At this point you can write the circuitry in SPICE and the chips in Verilog and simulate the whole old console clock by clock down to the transistor level and still get a playable game out of it
Of course this is only viable until say… before the 3D era or so
This gets done with FPGA systems like the MiSTer and there are N64 and PSX Cores for the MiSTer, a Saturn Core is in development.
If you go old enough, the problem often falls in the imperfections of the tech. When you simulate the whole console perfectly, you are idealizing a system that was far from perfect, and you might miss real features that depended on that.