[danbolt]

I can imagine reworking the x86 processor should be straightforward, but I'd be curious about the cost of emulating the proprietary hardware inside the Original Xbox (eg: render pipeline, memory architecture, I/O, etc.).

An example of this sort of thing can be well-observed emulating the Nintendo 64. The CPU is a plain-standard MIPS III, but emulating the console's graphics chip hasn't always been accurate for a long time. Disney-released games on the Nintendo Wii would toy with the write-back cache to prevent emulators from booting their games.[1]

I can imagine the largest amounts of difficulty are outside the CPU for a polished-enough project.

[1] https://dolphin-emu.org/blog/2017/02/01/dolphin-progress-rep...