Interrupts and exceptions are special kinds of control transfer; they work somewhat like unprogrammed CALLs. They alter the normal program flow to handle external events or to report errors or exceptional conditions. The difference between interrupts and exceptions is that interrupts are used to handle asynchronous events external to the processor, but exceptions handle conditions detected by the processor itself in the course of executing instructions.
There are two sources for external interrupts and two sources for exceptions:
(Non-Maskable Interrupt) pin.
trigger exceptions. These instructions are often called "software interrupts", but the processor handles them as exceptions.
This chapter explains the features that the 80386 offers for controlling and responding to interrupts when it is executing in protected mode.