Writing boot ROM code for the 68K [at Atari, not IBM...] was a lot of fun. For instance, the first thing we needed to do, before we could use any RAM, was to size the available RAM; this code ran a little memory test using just the 16 registers (and no stack, of course). Didn't take long to write, but it was a neat little puzzle.
Writing embedded software is neat. I still get a rush when a new design wakes up and prints out "Hello world!" on a serial port, and on the ST it was way cool when the floppy drive did its first seek.
"Hey guys, watch this!"
Grknnnnkknknkg
Little things. :-)
Don't know if you could do CPLD initialization with the same constraints, but it doesn't seem that hard . . . :-)
Motorola seemed to run out of 68K gas in the late 1980s. Maybe they were distracted? They developed the 88000 RISC, and at Apple we actually had some NuBus boards that we were urged to write software for, but that effort wasn't terribly well organized and ultimately fizzled (one fine day we were told to immediately rip out all our 88K dev boards and return them. Something contractual probably fell apart, and we guessed that some lawyers had gone non-linear...)