Unsafe FPU manipulation functions.
executes the computation
that the FPU control words are set to avoid problems from excess
precision. See the libqd documentation for further details.
This function is unsafe in a threaded runtime as Haskell threads can migrate between OS threads, moreover there is no checking for nested calls - this results in race conditions.
Some steps can be taken to mitigate some of this badness; perhaps
using (for example)