On receiving an interrupt from an I/O device, the CPU:

Question

Question

This question was previously asked in

ESE Electronics 2010 Paper 2: Official Paper

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Halts for a predetermined time
Branches off to the interrupt services routine after completion of the current instruction
Branches off to the interrupt service routine immediately
Hands over control of address bus and data bus to the interrupting device

Answer 1

Concept:

When CPU executing the same task & meanwhile it receives an interrupt then,

I) First it will finish the current task

II) After completion of current instruction it will branches off to the interrupt service routine.

ISR:

It stands for Interrupt service routine or also known as an interrupt handler.

It is a software process invoked by an interrupt request from a hardware device.

It handles the request and sends it to the CPU i.e. interrupting the active process. When the ISR is complete, the process is resumed.