Provide partial RTOS API for bare metal builds - things that
can be done in a single threaded environment.
Allows more code to work in both RTOS and bare metal builds without
change, and in particular gives easy access to the ability to
efficiently wait for something occurring in interrupt.
Available in bare-metal:
* ThisThread
* osThreadFlagsSet to set flags on main thread (can be set from IRQ)
* EventFlags (can be set from IRQ)
* Semaphores (can be released from IRQ)
* Mutex (dummy implementation)
Not useful:
* ConditionVariable (could only be signalled from 2nd thread)
* RtosTimer (calls in a second thread context)
* Thread
Unimplemented:
* Mail, Queue, MemoryPool
Possible future work:
* ConditionVariableCS to act as IRQ signalled ConditionVariable
- Hide protected member structures from doxygen.
- Add some more details/comments to the example.
- Add some defined/undefined behaviours.
- Add some additional details to function documentation
Given the 64-bit timebase, add wait_until to ConditionVariable.
Move the timeout example to wait_until(), and give wait_for() an
alternative example, as it's no longer the best option for a
timeout.
Tidy up - remove the redundant RESUME_SIGNAL definition.