Hi Students here you’ll learn different function of CPU which is also called processor. It is located inside the system unit. It performs the analytical, computational and logical function that occurs inside the system. The CPU operates by executing a programme, process data and sends the result at the output, which may be a printer or video display unit. The processor controls the operation of the computer.It fetches instructions from main storage interprets them and issues the necessary signals. It also directs all hardware operations. It consists of the following three components.
The CPU has memory of its own. This memory is divided into small parts. Each part is called a register. If the CPU wants to store something, say a number or a main memory address it stores it in one of its registers.
Arithmetic & Logic Unit:
ALU's are designed to perform the four basic arithmetic operations add, subtract, multiply and divide and logic operations such as less than, equal to, greater than.
Control Unit:
ALU and CU combine together to form of the brain of the computer known as CPU. It is responsible for activating and controlling the operations of other units of a computer system.
Main functions of CPU.
The functions of the central processing units are as follows.
i. Accepts information and data from the input unit.
ii. Stores all the instructions and the data in memory and retrieves the relevant information as and when required.
iii. Interprets the instructions and sends commands to relevant unit.
iv. Performs all the arithmetic and logical operations in the Arithmetic and Logical Unit (ALU).
v. Controls and co-ordinates the activities of all other units.
vi. Sends the results of the output unit when required.
The ALU of a computer system is the place where the actual execution of the instructions takes place during the processing operation.
It has two main functions:
a) It carries out the arithmetic e.g. add, subtract, multiply and divide.
b) It performs certain logical operations e.g. testing whether two data items match.
Data items about to be processed are taken from main storage, as directed by CU and pass via the MDR into the data registers in the ALU, where they are stored. This step is called as loading data into the accumulator from main memory.
The ALU then performs the required operation(s) on the data (e.g. adding) as directed by CU. The ALU leaves the results in a data register. Then results are taken from data registers and placed in main storage, again under the direction of the CU. This step is called as 'storing' data. Some logical operations of the ALU give the computer its decision-making ability.