What is The Difference Between RISC and CISC Architecture

The architecture of the Central Processing Unit (CPU) operates the capacity to function from “Instruction Set Architecture” to where it was designed. The architectural design of the CPU is Reduced instruction set computing (RISC) and Complex instruction set computing (CISC). CISC has the capacity to perform multi-step operations or addressing modes within one instruction set. It is the CPU design where one instruction works several low-level acts. For instance, memory storage, loading from memory, and an arithmetic operation. Reduced instruction set computing is a Central Processing Unit design strategy based on the vision that basic instruction set gives a great performance when combined with a microprocessor architecture which has the capacity to perform the instructions by using some microprocessor cycles per instruction. This article discusses the difference between the RISC and CISC architecture. The hardware part of the Intel is named as Complex Instruction Set Computer (CISC), and Apple hardware is Reduced Instruction Set Computer (RISC).

Difference-between-RISC-and-CISC
Difference-between-RISC-and-CISC

Difference between RISC and CISC Architecture

Before we discuss the differences between the RISC and CISC architecture let us know about the concepts of RISC and CISC

What is RISC?

A reduced instruction set computer is a computer which only uses simple commands that can be divided into several instructions which achieve low-level operation within a single CLK cycle, as its name proposes “Reduced Instruction Set”.

RISC Architecture

The term RISC stands for ‘’Reduced Instruction Set Computer’’. It is a CPU design plan based on simple orders and acts fast.

RISC Architecture
RISC Architecture

This is small or reduced set of instructions. Here, every instruction is expected to attain very small jobs. In this machine, the instruction sets are modest and simple, which help in comprising more complex commands. Each instruction is of the similar length; these are wound together to get compound tasks done in a single operation. Most commands are completed in one machine cycle. This pipelining is a crucial technique used to speed up RISC machines.

What is CISC?

A complex instruction set computer is a computer where single instructions can perform numerous low-level operations like a load from memory, an arithmetic operation, and a memory store or are accomplished by multi-step processes or addressing modes in single instructions, as its name proposes “Complex Instruction Set ”.

CISC Architecture

The term CISC stands for ‘’Complex Instruction Set Computer’’. It is a CPU design plan based on single commands, which are skilled in executing multi-step operations.

CISC Architecture
CISC Architecture

CISC computers have small programs. It has a huge number of compound instructions, which takes a long time to perform. Here, a single set of instruction is protected in several steps; each instruction set has additional than 300 separate instructions. Maximum instructions are finished in two to ten machine cycles. In CISC, instruction pipelining is not easily implemented.

Difference between RISC and CISC Architecture

Difference between RISC and CISC
Difference between RISC and CISC

 

RISC

CISC

1. RISC stands for Reduced Instruction Set Computer. 1. CISC stands for Complex Instruction Set Computer.
2. RISC processors have simple instructions taking about one clock cycle. The average clock cycle per instruction (CPI) is 1.5 2. CSIC processor has complex instructions that take up multiple clocks for execution. The average clock cycle per instruction (CPI) is in the range of 2 and 15.
3. Performance is optimized with more focus on software 3. Performance is optimized with more focus on hardware.
4. It has no memory unit and uses a separate hardware to implement instructions.. 4. It has a memory unit to implement complex instructions.
5. It has a hard-wired unit of programming. 5. It has a microprogramming unit.
6. The instruction set is reduced i.e. it has only a few instructions in the instruction set. Many of these instructions are very primitive. 6. The instruction set has a variety of different instructions that can be used for complex operations.
7. The instruction set has a variety of different instructions that can be used for complex operations. 7. CISC has many different addressing modes and can thus be used to represent higher-level programming language statements more efficiently.
8. Complex addressing modes are synthesized using the software. 8. CISC already supports complex addressing modes
9. Multiple register sets are present 9. Only has a single register set
10. RISC processors are highly pipelined 10. They are normally not pipelined or less pipelined
11. The complexity of RISC lies with the compiler that executes the program 11. The complexity lies in the microprogram
12. Execution time is very less 12. Execution time is very high
13. Code expansion can be a problem 13. Code expansion is not a problem
14. Decoding of instructions is simple. 14. Decoding of instructions is complex
15. It does not require external memory for calculations 15. It requires external memory for calculations
16. The most common RISC microprocessors are Alpha, ARC, ARM, AVR, MIPS, PA-RISC, PIC, Power Architecture, and SPARC. 16. Examples of CISC processors are the System/360, VAX, PDP-11, Motorola 68000 family, AMD and Intel x86 CPUs.
17. RISC architecture is used in high-end applications such as video processing, telecommunications and image processing. 17. CISC architecture is used in low-end applications such as security systems, home automation, etc.

This article discusses the concepts of RISC, CISC and its differences. We hope that you have got a better understanding of this concept. Furthermore, for any doubts regarding this concept, or implementation of any electrical and electronic projects, please give your feedback by commenting on the comment section below

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