Various Components of a CPU

Various Components of the CPU 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 Micro-programmable 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 a 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.