1.3 Central Processing Unit (CPU)

  1.3 Central Processing Unit (CPU)

 

·       The CPU (Central Processing Unit) is known as the brain of the computer which receives data from the input unit, processes instructions, and sends results to the output unit.

·       It performs calculations, logical operations, and decision-making tasks essential for running programs and managing system operations.

·       Intel CPUs (e.g., Intel Core i5, i7, i9), AMD CPUs (e.g., Ryzen series, EPYC), Apple CPUs(M1, M2), ARM CPUs ((e.g., Qualcomm Snapdragon, MediaTek)), etc. are popular examples of CPUs.

 

1.3.1 Function of the CPU

 

Fetching - CPU takes (fetches) instructions or data from the main memory (RAM).

Decoding - CPU interprets (decodes) the fetched instructions to understand what action is required.

Executing - CPU carries out the instruction (arithmetic, logic, data movement, or hardware control).

Storing - CPU stores the result in memory or sends it to an output device.

Managing Interrupts - CPU handles signals (interrupts) from hardware or software to ensure smooth and efficient processing.

 

In short with Example (25 + 10):

·        Fetch → Get the problem from memory.

·        Decode → Understand it’s an addition.

·        Execute → Do 25 + 10 = 35.

·        Store → Save result (35) in memory to display.

·        Manage Interrupts → Handle side tasks (e.g., notifications).

 

1.3.2 Components of the CPU: Control Unit, Arithmetic and Logic Unit, and Memory Unit.

 

·       The speed of a computer depends mainly on its microprocessor.

·       The microprocessor has three main parts. Control Unit (CU),  Arithmetic Logic Unit (ALU) and Memory Unit (Registers)

 

Control Unit (CU)

“The Control Unit (CU) directs and coordinates all operations of the computer by controlling the flow of data between the CPU, memory, and input/output devices.”

 

Arithmetic Logic Unit (ALU)

“The Arithmetic Logic Unit (ALU) is the part of the CPU that performs all arithmetic operations (addition, subtraction, multiplication, division) and logical operations (>, <, =, ≠, AND, OR, NOT).”

 

Memory Unit (MU)

The Memory Unit (MU) is the part of the CPU that stores data, instructions, and results temporarily during processing, so they can be quickly accessed by the Control Unit and ALU.

 

Registers

Registers are very small, high-speed storage locations inside the CPU used to hold data, instructions, or results temporarily during processing.”