.. highlight:: c
.. _libmaple-util:

``<libmaple/util.h>``
=====================

.. TODO [0.2.0?] clean this up.

Miscellaneous utility macros and procedures.

.. contents:: Contents
   :local:

Bit Manipulation
----------------

The following macros are useful for bit manipulation.

.. doxygendefine:: BIT
.. doxygendefine:: BIT_MASK_SHIFT
.. doxygendefine:: GET_BITS
.. doxygendefine:: IS_POWER_OF_TWO

Failure Routines
----------------

``throb()`` is called by various routines to throb a built-in
LED. **Usually, you shouldn't call it yourself**; use something like
``ASSERT(0)`` (or the libc ``abort()`` function) instead.

.. doxygenfunction:: throb

Asserts and Debug Levels
------------------------

The level of libmaple's assertion support is determined by
``DEBUG_LEVEL``, as follows:

.. doxygendefine:: DEBUG_LEVEL

The current assert macros are ``ASSERT()`` and ``ASSERT_FAULT()``.
``ASSERT()`` is checked when ``DEBUG_LEVEL >= DEBUG_ALL``.
``ASSERT_FAULT()`` is checked whenever ``DEBUG_LEVEL >= DEBUG_FAULT``.

As explained above, an assert macro is checked when the current
``DEBUG_LEVEL`` is high enough.  If the debug level is too low, the
macro expands  into a no-op that gets compiled away.

If an assertion fails, execution is halted at the point of the failed
assertion.  When libmaple has been configured properly (Wirish
performs this configuration by default), the built-in LED throbs in a
smooth pattern to signal the failed assertion (using
:c:func:`throb()`), and the file and line where the assert failed are
transmitted to the user as detailed in :ref:`lang-assert`.