Q. Show the liability of CPU in interrupt cycle?

In the interrupt cycle the liability of CPU/Processor is to ensure whether any interrupts have happened checking presence of interrupt signal. In case no interrupt requires service then processor carry on to next instruction of current program.  In case an interrupt requires servicing then interrupt is processed as per below.

• Suspend execution of current program plus save its context.
• Set PC (Program counter) to starting address of ISR (interrupt service routine) of interrupt acknowledged.
• The processor then executes instructions in interrupt-servicing program. Interrupt servicing programs are generally part of operating system.
• After finishing interrupt servicing program CPU can resume program it has suspended in step 1 above.