What is the difference between FIQ and IRQ in ARM?
What is the difference between FIQ and IRQ in ARM?
FIQ and IRQ are two different types of interrupts. In order to support these two different interrupts, ARM provides corresponding processor modes called FIQ and IRQ (ARM has 7 processing modes). FIQ has a higher priority than IRQ. If FIQ and IRQ are generated at the same time, FIQ is processed first.
What is difference between FIQ and IRQ why FIQ response is fast than IRQ?
FIQ has higher priority than IRQ. This means that when the core takes an FIQ exception, it automatically masks out IRQs. An IRQ cannot interrupt the FIQ handler. The opposite is not true – the IRQ does not mask FIQs and so the FIQ handler (if used) can interrupt the IRQ.
What are types of ARM exceptions?
ARM Exceptions
| Event | Exception | Mode |
|---|---|---|
| FIQ input asserted | Fast Interrupt (FIQ) | FIQ |
| IRQ input asserted | Normal Interrupt (IRQ) | IRQ |
| Executing BKPT 3 or instruction at invalid address | Instruction Fetch Memory Abort (Prefetch Abort) | Abort |
| Executing SWI instruction | Software Interrupt (SWI) | Supervisor |
What is ARM register?
ARM processors provide general-purpose and special-purpose registers. Some additional registers are available in privileged execution modes. In all ARM processors, the following registers are available and accessible in any processor mode: 13 general-purpose registers R0-R12. One Stack Pointer (SP).
What is the difference between IRQ and Fiq in case of arm?
What is the difference between IRQ and FIQ in case of ARM? ARM treats FIQ (Fast interrupt request) at a higher priority as compared to IRQ (interrupt request). When an IRQ is executing an FIQ can interrupt it while vice versa is not true. ARM uses a dedicated banked out register for FIQ mode ; register numbers R8-R12.
What’s the difference between Fiq and IRQ in Linux?
So when an FIQ comes these registers are directly swapped with the normal working register and the CPU need not take the pain of storing these registers in the stack. So it makes it faster.
Which is higher priority an IRQ or a FIQ?
The top answer in the SO link you shared suggests that an FIQ is a higher priority interrupt than IRQ and if a FIQ occurs,other interrupts get disabled. Do those IRQ’s get reenabled after the FIQ is serviced? – AkshayImmanuelD Mar 24 ’16 at 9:06 When a FIQ is active, the IRQ handler is disabled. The IRQ hardware itself isn’t disabled.
What’s the difference between Fiq and fast interrupt request?
Any help would be great. Thanks. FIQ (Fast Interrupt reQuest) is basically a higher priority interrupt (which will interrupt even the interrupt handler of a normal IRQ). See this excellent anser on stack overflow – jms Mar 24 ’16 at 8:02