Components of CPU and Their Functions in Computer

In this article, we will take a look at the main 6 components of the Central Processing Unit, also known as the brain of the computer.

As we all know, the CPU is responsible for all the major tasks like processing data and instructions inside the computer system. But, all this is possible only because of the components present inside the CPU which divide the work among themselves and process it at a fast pace to produce the desired result. We will study each of these components in the subsequent parts.

Components of CPU and Their Functions

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1. Control Unit (CU)

The control unit controls the way input and output devices, the Arithmetic, and Logic Unit, and the computer’s memory respond to the instruction sent to the CPU. It fetches the input, converts it in a decoded form, and then sends it for processing to the computer’s processor, where the desired operation is performed. There are two types of Control units – the Hardwire CU and the Microprogrammable CU.

Functions of Control Unit:

• It controls the sequence in which instructions move in and out of the processor and also the way the instructions are performed.
• It is responsible for fetching the input, converting it into signals, and storing it for further processing.
• It controls the functioning of other components of the CPU like ALU and Registers.

2. Arithmetic Logic Unit (ALU)

The Arithmetic and Logical Unit is responsible for arithmetical and logical calculations as well as taking decisions in the system. It is also known as the mathematical brain of the computer. The ALU makes use of registers for the calculations. It takes input from input registers, performs operations on the data, and stores the output in an output register.

Functions of ALU:

• It is mainly used to make decisions like performing arithmetic and logical operations.
• It acts as a bridge between the computer’s primary memory and the secondary memory. All information that is exchanged between the primary and secondary memory passes through the ALU.

3. Registers

Registers are part of a computer’s memory that is used to store the instructions temporarily to provide the processor with the instructions at times of need. These registers are also known as Processor registers as they play an important role in the processing of data. These registers store data in the form of memory address and after the processing of the instruction present at that memory address is completed, it stores the memory address of the next instruction. There are various kinds of registers that perform different functions.

Functions of Registers:

• Input registers are used to carry the input.
• Output registers are used to carry the output.
• Temporary registers store data temporarily.
• Address registers store the address of the memory.
• The program counter stores the address of the instructions.
• Data registers hold the memory operand.
• Instruction registers hold the instruction codes.

4. Cache

The cache is a type of Random Access Memory that stores small amounts of data and instructions temporarily which can be reused as and when required. It reduces the amount of time needed to fetch the instructions as instead of fetching it from the RAM, it can be directly accessed from Cache in a small amount of time.

Functions of Cache:

• They reduce the amount of time needed to fetch and execute instructions.
• They store data temporarily for later use.

5. Buses

A bus is a link between the different components of the computer system and the processor. They are used to send signals and data from the processor to different devices and vice versa. There are three types of buses – Address bus which is used to send memory address from process to other components. The data bus, which is used to send actual data from the processor to the components, and the Control bus, used to send control signals from the processor to other devices.

Functions of Bus:

• It is used to share data between different devices.
• It supplies power to different components of the system.

6. Clock

As the name suggests, the clock controls the timing and speed of the functions of different components of the CPU. It sends out electrical signals which regulate the timing and speed of the functions.

Functions of Clock:

• It maintains the synchronization of the components of the computer system.
• It keeps track of the current date and time.

So, this is all about the major components of the CPU which are responsible for the smooth processing of instructions and data in the computer system.