Fast interrupt request
Fast interrupt request (FIQ) is a specialized type of interrupt request, which is a standard technique used in computer CPUs to deal with events that need to be processed as they occur, such as receiving data from a network card, or keyboard or mouse actions. FIQs are specific to the ARM architecture, which supports two types of interrupts; FIQs for fast, low-latency interrupt handling, and standard interrupt requests (IRQs), for more general interrupts.
An FIQ takes priority over an IRQ in an ARM system. Also, only one FIQ source at a time is supported. This helps reduce interrupt latency as the interrupt service routine can be executed directly without determining the source of the interrupt. A context save is not required for servicing an FIQ since it has its own set of banked registers. This reduces the overhead of context switching.
- ^ "Loading this site". Archived from the original on 2008-05-17. Retrieved 2014-02-10.
- ^ "Computers as Components: Principles of Embedded Computing System Design (3rd Edition)". Archived from the original on 22 Feb 2014.
- Debugging ARM kernels using fast interrupts, LWN.net, May 29, 2014, by Daniel Thompson