Merge branch 'master' into debug-serialusb.

Chose debug-serialusb version in cases of conflict.

Conflicts:
	libmaple/usb/usb_callbacks.c

1 files changed, 49 insertions, 0 deletions

diff --git a/docs/source/lang/api/abs.rst b/docs/source/lang/api/abs.rst
new file mode 100644
index 0000000..0cc6c23
--- /dev/null
+++ b/docs/source/lang/api/abs.rst
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+.. highlight:: cpp
+
+.. _lang-abs:
+
+
+abs()
+======
+
+(Macro) computes the absolute value of a number.
+
+Syntax
+------
+
+::
+
+   abs(x)
+
+Parameters
+----------
+
+**x**: the number.
+
+Returns
+-------
+
+**x**: if **x** is greater than or equal to 0.
+
+**-x**: if **x** is less than 0.
+
+Warning
+-------
+
+Because of the way ``abs()`` is implemented, avoid using other
+functions or causing side effects inside the parentheses, as it may
+lead to incorrect results::
+
+    abs(a++);   // avoid this - yields incorrect results
+
+    abs(a);       // use this instead -
+    a++;          // keep other operations outside abs()
+
+
+Arduino Compatibility
+---------------------
+
+Maple's implementation of ``abs()`` is compatible with Arduino.
+
+
+.. include:: cc-attribution.txt