I recently had an interview at one of the big chip designers, and towards the end they gave a few basic computer architecture and assembly brainteaser questions

I recently had an interview at one of the big chip designers, and towards the end they gave a few basic computer architecture and assembly brainteaser questions. One of them was whether I was aware of a smaller instruction for zeroing a register, and I did manage to guess xor after a little thought. It's a trivial idea, but very satisfying to realize for the first time.