I've seen this and others, but they're brittle. Terminating that count loop for any other reason, for example, will break it. There's another one for reversin

I've seen this and others, but they're brittle. Terminating that count loop for any other reason, for example, will break it. There's another one for reversing bytes in an integer, but I ended up hard-coding the intrinsic due to brittleness.