fma.c, fms.c: added a comment about apparently incorrect scaling.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@5468 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 3 insertions, 0 deletions

diff --git a/fma.c b/fma.c
index a8f617e84..726d77d56 100644
--- a/fma.c
+++ b/fma.c
@@ -272,6 +272,9 @@ mpfr_fma (mpfr_ptr s, mpfr_srcptr x, mpfr_srcptr y, mpfr_srcptr z,
                 MPFR_ASSERTN (! MPFR_OVERFLOW (flags));  /* TODO... */
                 MPFR_ASSERTN (! MPFR_UNDERFLOW (flags));  /* not possible */
                 inex2 = mpfr_div_2ui (s, s, scale, GMP_RNDN);
+                /* FIXME: this seems incorrect. GMP_RNDN -> rnd_mode?
+                   Also, handle the double rounding case:
+                   s / 2^scale = 2^(emin - 2) in GMP_RNDN. */
                 if (inex2)  /* underflow */
                   inexact = inex2;
               }