.. include:: <mmlalias.txt>


Firmware: Collapse Three Threads Into One (Eventloop)
=====================================================

.. topic:: See also

   * :doc:`../../polling/index`

Problem: Too Many Threads
-------------------------

* Stacksize not zero
* |longrightarrow| Memory overhead

.. image:: fsm-kill-threads.svg
   :scale: 80%

This Can Be Done Better
-----------------------

.. image:: fsm-eventloop.svg
   :scale: 80%

Plan
----

* Collapse all in one thread
* First: didactically poll (``take_noblock()``) each of the three
  semaphores
* |longrightarrow| :doc:`event loop <../../polling/index>` to the
  rescue
* Added benefit: remove mutex

``main()``: Single Thread, Waiting For Three Semaphores
-------------------------------------------------------

.. literalinclude:: code/main.cpp
   :caption: :download:`code/main.cpp`
   :language: c++

FSM: Look Ma, No Mutex
----------------------

.. literalinclude:: code/fsm.h
   :caption: :download:`code/fsm.h`
   :language: c++

.. literalinclude:: code/fsm.cpp
   :caption: :download:`code/fsm.cpp`
   :language: c++