OP is talking about a bare-metal world where you might care about things like: - how many instructions execute between an interrupt trigger and your vector get

OP is talking about a bare-metal world where you might care about things like: - how many instructions execute between an interrupt trigger and your vector getting executed - if some piece of data is getting stored in text, data, or runtime space (harvard v single address spaces can make things weird) - minimizing or not using a stack to avoid clobbering your puny memory - other misc. things that even hardware vendors don't make easy (or sometimes possible) to find Honestly I don't think that even C is great for these things, but I mostly blame hardware vendors/architects for this situation. They all like to roll their own standards for documentation, language interfaces, etc. Sometimes it feels like a competition to see who can come up with the worst.