[clarified] Software debounce without millis and attiny13a, respectively

septillion:
Mehh, it does debounce. In a very ugly and blocking way but it does debounce. Will even give some extra headaches when you want to read multiple buttons etc.

Aka, why make it hard and not just implement millis() and have all the timing issues under control without wasting everything...

That isn't a debounce routine, that is a "Stop EVERYTHING until the button is released!" routine.