Summarize the steps performed by the CPU when an interrupt occurs.

Answer 1

Step 1 − First, device issues interrupt to CPU.

Step 2 − Then, the CPU finishes the execution of the current instruction.

Step 3 − CPU tests for pending interrupt requests. If there is one, it sends an acknowledgment to the device, removing its interrupt signal.

Step 4 − CPU saves the program status word onto the control stack.

Step 5 − CPU loads the location of the interrupt handler into the PC register.

Step 6 − Save the contents of all registers from the control stack into memory.

Step 7 − Find the cause of the interrupt, interrupt type, or invoke the appropriate routine.

Step 8 − Restore saved registers from the stack.

Step 9 − Restore the PC to dispatch the original process.