Most if not all RTOS's swap threads by saving and restoring the stack and registers. Most of the ones I've seen you can turn off preemption and you then have co

Most if not all RTOS's swap threads by saving and restoring the stack and registers. Most of the ones I've seen you can turn off preemption and you then have cooperative threads. It's much easier to deal with shared memory with cooperative threads at the expense of higher latency.