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Diffstat (limited to 'source/libmaple/api/util.rst')
| -rw-r--r-- | source/libmaple/api/util.rst | 47 |
1 files changed, 43 insertions, 4 deletions
diff --git a/source/libmaple/api/util.rst b/source/libmaple/api/util.rst index 50ffe76..06c9246 100644 --- a/source/libmaple/api/util.rst +++ b/source/libmaple/api/util.rst @@ -4,9 +4,48 @@ ``util.h`` ========== -[Stub] support. +.. TODO [0.2.0?] clean this up. -Library Documentation ---------------------- +Miscellaneous utility macros and procedures. -.. doxygenfile:: util.h +.. contents:: Contents + :local: + +Bit Manipulation +---------------- + +:: + + #define BIT(shift) (1UL << (shift)) + #define BIT_MASK_SHIFT(mask, shift) ((mask) << (shift)) + /** Gets bits m to n of x */ + #define GET_BITS(x, m, n) ((((uint32)x) << (31 - (n))) >> ((31 - (n)) + (m))) + #define IS_POWER_OF_TWO(v) (v && !(v & (v - 1))) + +Failure Routines +---------------- + +.. 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`. |