One of my first paid gigs was to write a debugger for a RIP implemented in 2900 bitslice. It was a specialized SIMD architecture. The debugger was written in C and ran on the bootloader processor, which I recall being a 68k. Having taken an architecture course as an undergrad I sort of knew what I was doing, and microcode is inherently simple compared to, for example, 64-bit x86. I recall thinking "this is what a really wide PDP-11 would be like." The project was also interesting in that my customer was one person: The guy who designed the processor and who was writing the microcode.