Apnote: Fast Interrupt Handling

Fast interrupt handling is important to system throughput and responsiveness. This application note describes a method to use existing Xtensa features and configuration options to support very fast interrupt handling. This note focuses on the interrupt handling case, i.e, that case where one task is running, but is preempted at some random point by an external or timer interrupt, which then performs an independent task. See http://www.tensilica.com/products/literature-docs/application-notes/system-software/interrupt-handling.htm