Embedded Systems Architecture

Context switch

The context switch procedure consists of getting the values of the CPU register during the execution and saving them at the bottom of the stack of the currently running task. Then, restore the values for the next task, to resume its execution. This operation must happen in the interrupt context, and its internal mechanisms are CPU-specific. On the reference platform, any interrupt handler can replace the current running task and restore another context, but this operation is more often done within interrupt service routines associated with system events. Cortex-M provides two CPU exceptions that are designed to provide the basic support for context switching, because they can be arbitrarily triggered in any context: PendSV ...