Complex instruction set computing (CISC ) is a processor design where single  instructions can execute several low-level operations (such as a load from memory, an arithmetic operation, and a memory store) or are capable of multi-step operations or addressing modes within single instructions. The term was retroactively coined in contrast to reduced instruction set computer (RISC) and has therefore become something of an umbrella term for everything that is not RISC, i.e. everything from large and complex mainframes to simplistic microcontrollers where memory load and store operations are not separated from arithmetic instructions.