CPU Architecture

A CPU/processor is the primary component of the computer. It is an integral component responsible for every single task performed by a PC. A CPU performs all types of processing operations; stores data, gives intermediate results, and further, controls all operation inside a computer.

The CPU has three main components as listed below:

• Control Unit (CU)
• Arithmetic Logic Unit (ALU)
• Memory or Storage Unit

Each CPU components is discussed as follows:

Control Unit (CU): This unit controls all computer parts but does not carry out any data processing operations. It performs the following functions:

• Controls data and transfer of instructions between other units of the computer. • Manages and coordinates all computer units.
• Decodes instructions from memory and directs the operation to be performed.
• Communicates with input/output devices for data transfer or result storage.

Arithmetic Logical Unit (ALU): This unit comprises two parts; arithmetic and logical. The arithmetic part performs mathematical operations such as addition, multiplication, division, etc. on the data. The logical part of ALU performs rational operations such as comparing, matching, merging of data, etc.

Memory Unit: This unit stores data, instructions and intermediate results. It also, propagates the information needed by the computer units. The Memory Unit is termed as an internal storage unit or main memory. The CPU is needed to run or execute a software program. A running software program is sequenced into instructions. This in turn utilises the ‘instruction set’ of CPUs and loads it into the system memory. The Instruction Set is the complete collection or set of instructions recognized by the processor of a computer. The CPU performs the following operations, once the instructions are loaded into the system memory.

• CU fetches the next instruction from memory to pipeline. It decodes the instruction in sequence, and executes or passes it to ALU.
• ALU performance the arithmetical and logical operations as per given instructions.
• Result of executed instruction is stored into a register or main memory.