[src/gamma.c] Corrected the FIXME comment concerning the underflow

detection.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@8185 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 4 insertions, 5 deletions

diff --git a/src/gamma.c b/src/gamma.c
index d8afd454e..13a920f17 100644
--- a/src/gamma.c
+++ b/src/gamma.c
@@ -379,11 +379,10 @@ mpfr_gamma (mpfr_ptr gamma, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
       mpfr_sin (GammaTrial, GammaTrial, MPFR_RNDN); /* sin(Pi*(2-x)) */
       /* if tmp is +Inf, there is an underflow, since the
          Pi*(x-1)/sin(Pi*(2-x)) term is larger than 1 in absolute value.
-         FIXME: The underflow is not guaranteed since the inverse of
-         the maximum finite number is approximatively twice the minimum
-         positive number in the extended exponent range. With this
-         explanation alone, the result with infinite tmp could also
-         be somewhere between about 1/2 * 2^emin and 2^emin.
+         FIXME: Mathematically, in absolute value, one has a value > 1
+         multiplied by a value less than approximately 2^emin (i.e.
+         twice the minimum positive number). This won't necessarily
+         yield an underflow.
          The sign is that of -sin(Pi*(2-x)). */
       if (mpfr_inf_p (tmp))
         {