This project from [3DSage] falls squarely in the latter category, with his completely DIY computer built component by component from scratch, including the machine code needed to run it.

I suppose the holy grail would be to bootstrap your custom CPU into a full-blown Linux system. That’s a big enough job that I haven’t done it. Although you might be more productive than I am ...

However, this low-level layer between hardware and machine code can also serve as a stealthy ... inspiration from a critical flaw in AMD's Zen processors, discovered by Google researchers earlier ...

a portmanteau of Python and Processing-in-Memory. PyPIM's new interface and development libraries would convert traditional, high-level Python commands into low-level, PIM-enabled machine code ...