Context Switching

In this lesson:

• what a context is and what a context switch saves/restores
• where the saved context lives (each task's own stack)
• the Cortex-M mechanism: SysTick → PendSV, PSP/MSP, auto-stacking
• the cost of switching (scheduler overhead)
• the gotchas: stack sizing, FPU context, switch frequency

This is the how under the scheduler, how a task is paused mid-flight and resumed perfectly.