Difference Between RISC and CISC

Computers Hardware Memory

In this post, we will understand the difference between RISC and CISC −

Microprocessors are classified based on the architecture (instruction set) into RISC and CISC.

RISC

It stands for Reduced Instruction Set Computer.
It is a microprocessor architecture that uses small instruction set of uniform length.
These simple instructions are executed in one clock cycle.
These chips are relatively simple to design.
They are inexpensive.
The disadvantage is that the computer has to repeatedly perform simple operations in order to execute a large program that has a large number of processing operations.
Examples of RISC chips include SPARC, POWER PC.
It has less number of instructions.
It has fixed-length encodings for instructions.
Simple addressing formats are supported.
It doesn’t support arrays.
It doesn’t use condition codes.
Registers are used for procedure arguments and return addresses.

Architecture of RISC:

CISC

It stands for Complex Instruction Set Computer.
This offers hundreds of instructions of different sizes to the users.
This architecture has a set of special purpose circuits which help execute the instructions at a high speed.
The instructions interact with memory using complex addressing modes.
These processors reduce the size of the program.
Consequently, they take less number of memory cycles to execute the programs.
The overall speed of execution is high.
Examples of CISC include Intel architecture, AMD.
It has variable-length encodings of instructions.
It supports array.
It has a large number of instructions.
Arithmetic and logical operations can be applied to memory and register operands.
Condition codes are used.
The stack is used for procedure arguments and return addresses.

Architecture of CISC

Updated on 29-Apr-2021 09:03:05

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