math: Add bitwise and/or functions

Just as `math "bitand(5,3)"` and `math "bitor(6,2)"`.

These cast to long long before doing their thing,
so they truncate to an integer, producing weird results with floats.

That's to be expected because float representation is *very*
different, and performing bitwise operations on floats feels quite useless.

Fixes #7281.

doc_src/cmds/math.rst

@@ -75,6 +75,7 @@ Functions
 - ``asin``
 - ``atan``
 - ``atan2``
+- ``bitand``, ``bitor`` and ``bitxor`` to perform bitwise operations. These will throw away any non-integer parts and interpret the rest as an int.
 - ``ceil``
 - ``cos``
 - ``cosh``
@@ -114,6 +115,10 @@ Examples
 
 ``math 0xFF`` outputs 255, ``math 0 x 3`` outputs 0 (because it computes 0 multiplied by 3).
 
+``math "bitand(0xFE, 0x2e)"`` outputs 46.
+
+``math "bitor(9,2)"`` outputs 11.
+
 Compatibility notes
 -------------------