How are game consoles reverse engineered so emulators are created?

Question

How do people reverse engineer consoles such as the Wii, to create emulators for their game executables?

Answer 1

As for the game consoles and such they are normally based off industry standard processors. The game company just buys the processor and uses it - they don't pump $200,000,000 into designing their own CPU and trying to compete with the likes of Motorola, Intel, Freescale etc.

These same industry standard processors frequently have industry standard debug ports, JTAG/BDM/NEXUS etc. The game console manufacturer has to debug their own device too! Those are frequently used to reverse engineer what the console is doing as it runs its operating system. It isn't always that simple since you may have to find ways to activate the debug features but this is a general overview.

For the emulator itself you need to emulate the hardware architecture and hardware itself. Once you can simulate this you can simply "run" the game console's operating system and games and they have no idea that they're not running on real hardware. There are many techniques to virtualize the hardware so it runs the code fast enough but that's a completely different topic.