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Ask HN: Favourite Assembly Instructions?
One for the low-level gurus among you: what is/are your favourite assembly-language instructions, accross the ages & instruction sets?
To get this started: for the good 'ol Z80, I'm torn between Decrement-and-Jump-if-Not-Zero (DJNZ), and Decimal Adjust Accumulator (DAA). Rarely used ComPare, Increment & Repeat (CPIR) could be another contender.
On RISC-V, I much like the Set-Less-Than (SLT..) instructions. Great for replacing conditional branches with branchless, sequential math.
Your favourites?