What is the difference between FIQ and IRQ interrupt system?

ARM calls FIQ the fast interrupt, with the implication that IRQ is normal priority. In any real system, there will be many more sources of interrupts than just two devices and there will therefore be some external hardware interrupt controller which allows masking, prioritization etc. of these multiple sources and which drives the interrupt request … Read more

When an interrupt occurs, what happens to instructions in the pipeline?

First, terminology: Usually, at Intel at least, an interrupt is something that comes from the outside world. Usually it is not synchronized with instructions executing on the processor, i.e. it is an asynchronous external interrupt. In Intel terminology an exception is something caused by instructions executing on the processor. E.g. a page fault, or an … Read more