CISC - complex instruction set computing

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). CISC processors are also capable of multi-step operations or addressing modes within single instructions. The hallmark of CISC processors is that memory load and store operations are performed along with arithmetic operations. In contrast to CISC designs, RISC uses uniform instruction length for almost all instructions and employ distinct load/store-instruction.
 The features below exclusive to CISC:

 - CISC chips have a large amount of different and complex instructions (variable length)
- CISC machines generally make use of complex addressing modes.
- Different machine programs can be executed on CISC machines (it's RISC that favours uniformity).
- CISC machines use micro-program control unit.
- CISC processors have limited number of registers (RISC design favours more registers).