Exam-style question
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A processor is executing a program when an interrupt occurs. Explain the sequence of actions that should allow the processor to service the interrupt and then resume the original program.
Model answer
What a good answer should say
- The processor temporarily stops following the normal Fetch-Execute sequence for the original program.
- It saves the volatile environment so that the current execution state is not lost.
- It then executes the appropriate interrupt service routine to deal with the interrupt.
- After servicing the interrupt, the saved environment is restored, allowing the processor to resume the original program.
Explanation
Why this works
The answer should present the process in a logical order: temporary diversion, saving the volatile environment, execution of the ISR, and restoration followed by continuation of the original program.
Common mistake
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