CISC (complex Instruction Set computer) is a processor design approach in which the control Unit contains a number of microelectronic circuit to generate a set of control signals and each microcircuitry is activated by a microcode. In Complex Instruction set computing single instruction can execute several low-level operations such as loadng from memory, arithmetic operation and a memory store. Also capable of multi-step operations and addressing modes within a single instruction.
The microprograming approach makes the processor slower compared to RISC approach. Examples of the CISC processors are Intel x86, Intel Pentium Pro etc.
- More Addressing Modes
- Slower Clock speed
- Few general purpose registers
- Feature rich Instructions
- More complex instruction
- Instruction pipeline cannot be implemented
- Shortens the execution time reducing the numbers of instructions per programs