Table of Content

What are Interrupts?

• Interrupts are messages to the Pentium chip.
• Interrupt is used to halt current activity and perform our requested job.
• When we generate an interrupt, the CPU suspends it current operation.
• CPU performs the job we requested, finishes our job and resumes its suspended job.
• We are interrupting the CPU, that is why, we call it interrupts!

Explanation Of Interrupt :

1. Suppose we have sample C Program to execute , Consider following code

int main()
{
int num1,num2,sum;

printf("Enter the number 1 : ");
scanf("%d",&num1);

printf("Enter the number 2 : ");
scanf("%d",&num2);

sum = num1 + num2;

printf("Sum : %d",sum);
return(0);
}

Above program is handed over to CPU for execution then CPU starts executing this program.While Executing Following Statement CPU is waiting for input from the user –

scanf("%d",&num1);

2. Then Current Program execution is halted and Control is given to the IO device i.e Keyboard to Enter the number.
3. As soon as User Enters the number , the CPU resumes execution of the remaining code.
4. The process of halting the Program execution in between is called interrupt.