Hi Stephen, as said in http://osdir.com/ml/sage-devel/2010-04/msg00598.html, you should contact Andreas Enge or Joris van der Hoeven who are specialists of this topic.
In particular you might have a look at MPFRCX (http://www.multiprecision.org/index.php?prog=mpfrcx). Paul Zimmermann -- To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
