What Is CPU ?
How CPU Works | CPU Functions | Definition
The CPU stands for, Central Processing Unit .The C P U is one the most important component, within a computer system. The CPU is also alternately referred to as a processor, central processor, or a microprocessor .
It is the C P U, that actually provides the processing power to the computer system. The C P U works at very high speed and performs millions of calculations per second in order to execute any program.
In this article , you will learn , what is CPU ? , How CPU works ? , Functions Of C P U and other important topics related to the Central Processing Unit.
What Is Central Processing Unit ?
What Is CPU ?
The computer systems are extensively used for various applications primarily due to its ability to process large volumes of data at very high speed . The computer system gets this ability due to an internal component called Central Processing Unit.
The CPU is an electronic component that is packed with integrated circuit ( IC ) chips . The CPU controls all the operations performed by the computer system. The C P U is also responsible to execute the computer program.
The C P U provides the processing power to the computer system . The computer hardware technology is growing at fast pace and new processors are being introduced in the market with significant improvement in the processing power.
The famous Moors law had predicted this rapid advancement in the computer hardware technology long back especially in the processing power of the C P U. As per this law , the C P U processing power will double every two years.
The commercial name of the C P U is “Microprocessor” or simply a processor. The CPU is said to be the brain of the computer system . The C P U performs all the arithmetic calculations and logical operations to perform various operations.
What Is Microprocessor ?
CPU Architecture
In order to understand the CPU architecture and the functions of internal components of the C P U , we need to first discuss , how C P U executes a program.
The Operating System ( OS ) loads the program to be executed into the main memory RAM. The C P U starts the program execution by fetching the data and program statements from the main memory into the C P U memory unit.
The C P U operates on the data as per the program instructions and stores the processed data back into the main memory RAM . The operating system sends this data to the output device such as monitor.
CPU Architecture
The Central Processing Unit ( C P U ) is internally consist of three major units . In other words , the C P U processing functions can be grouped into three units . These units include :
- Arithmetic Logic Unit ( ALU ) .
- Control Unit ( CU ).
- Memory Unit .
Arithmetic Logic Unit ( ALU )
The Arithmetic Logic Unit ( ALU ) of the CPU , performs, all the arithmetic, and logical operations. The ALU performs the desired operation on the data as specified in the program code. The Control unit decodes the program instruction for the operation to be performed by the ALU.
Control Unit ( CU )
The Control Unit ( CU ) Of the C P U controls the functioning of all the internal components and other devices connected to the system. The control unit also decodes the each program instruction as per the OPCODE and ALU then performs the operation on the OPERAND.
CPU Memory Unit
The C P U works at very high speed and makes use of high speed internal memory called Registers . The memory unit, within a C P U consist of, High speed memory , that is used by the C P U, to store the data during the program execution.
CPU And Motherboard Architecture
The motherboard is the main printed circuit board ( PCB ) in a computer system where all the major system components are interconnected.
The microprocessor chip is placed on the motherboard into the processor socket which holds the processor chip . The C P U socket comes with a liver locking mechanism which firmly holds the processor chip into the C P U socket.
The CPU works at very high speed that generates considerable heat . And therefore , a heat-sink is mounted on the top of the processor chip which protects the processor chip from damage due to excessive heat.
Computer System Motherboard
How CPU Executes Program ?
Machine Cycle | Instruction Cycle
The main function of the CPU is to execute the program and the operating system allocates the necessary resources to run the program.
The program contains number of program statements which are instructions to the CPU to perform a specific task. The C P U has to repetitively perform the Instruction Cycle ( Machine Cycle ) which is the basic operation of the CPU.
The machine cycle consist of, four basic operations performed by the CPU . These four instruction cycle , operations include
- 1. FETCH
- 2. DECODE
- 3. EXECUTE
- 4. STORE
What Is Machine Cycle ?
The machine cycle is the main activity performed by the central processing unit ( CPU ) to execute the program instruction. The Machine cycle is also alternately referred to as Instruction cycle .
However , the machine cycle is a part of instruction cycle .Whereas, the instruction cycle is the process initiated by the CPU to execute one program instruction .
CPU Instruction Cycle
The instruction cycle is the process used by the C P U to execute one instruction. The machine cycle is just a one step of instruction cycle . Depending upon the complexity of the program instruction , the C P U might need one or more machine cycles to execute one instruction.
The C P U takes minimum one and maximum four machine cycle to execute one program instruction. Whereas one machine cycle takes twelve clock cycles.
CPU Functions
The C P U performs some of the most important functions in a computer System and these functions include :
- To Perform Arithmetic Calculation Operations.
- To Perform Logical Operations.
- To Control Functions Of Other Hardware Components.
- To Fetch the Data And Program Instructions From Main Memory.
- To Decode the Program Instructions.
- To Operate On Data As per Program Instructions.
- To Store Data After Processing.
- To Continuously Execute Instruction Cycle / Machine Cycle.
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