Describe interrupt handling procedure.

The interrupt handler is also called as Interrupt service routine (ISR). There are different types of interrupt handler which will handle different interrupts. For example for the clock in a system will have its interrupt handler, keyboard it will have its interrupt handler for every device it will have its interrupt handler.

The main features of the ISR are -

·    Interrupts can occur at any time they are asynchronous. ISR's can call for asynchronous interrupts.

·    Interrupt service mechanism can call the ISR’s from multiple sources:

·    ISR's can handle both mask-able and non-mask-able interrupts. An instruction in a program can disable or enable an interrupt handler call.

·    ISR on beginning of execution it will disable other devices interrupt services. After completion of the ISR execution it will re initialize the interrupt services.

·    The nested interrupts are allowed in ISR for diversion to other ISR.

Type of Interrupt Handlers:

(i) First Level Interrupt Handler (FLIH) is hard interrupt handler or fast interrupt handler. These interrupt handlers have more jitter while process execution and they are mainly mask-able interrupts.

(ii) Second Level Interrupt Handler (SLIH) is soft interrupt handler and slow interrupt handler. These interrupt handlers are having less jitter.