Comment by topspin

That's an excellent rebuttal to this common factoid.

Recently I encountered a view that has me thinking. They characterized the PIO "ISA" in the RPi MCU as CISC. I wonder what you think of that.

The instructions are indeed complex, having side effects, implied branches and other features that appear to defy the intent of RISC. And yet they're all single cycle, uniform in size and few in number, likely avoiding any microcode, and certainly any pipelining and other complex evaluation.

If it is CISC, then I believe it is a small triumph of CISC. It's also possible that even characterizing it as and ISA at all is folly, in which case the point is moot.