There's a similar project for the Acorn BBC Micro called PiTubeDirect, which allows the Pi to emulate several different CPUs, while connected to the BBC Micro's

There's a similar project for the Acorn BBC Micro called PiTubeDirect, which allows the Pi to emulate several different CPUs, while connected to the BBC Micro's "tube" second processor slot. https://github.com/hoglet67/PiTubeDirect https://github.com/hoglet67/PiTubeDirect (The BBC Micro itself was quite remarkable for supporting multiple processors, which did not have to be the same architecture as the host 6502. Amazing for 1981.)