fixed pb with count_leading_zeros (n=0)

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2286 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 4 insertions, 1 deletions

diff --git a/exp_2.c b/exp_2.c
index a46695ad9..44091eb01 100644
--- a/exp_2.c
+++ b/exp_2.c
@@ -117,7 +117,10 @@ mpfr_exp_2 (mpfr_ptr y, mpfr_srcptr x, mp_rnd_t rnd_mode)
   n = (int) (mpfr_get_d1 (x) / LOG2);
 
   /* error bounds the cancelled bits in x - n*log(2) */
-  count_leading_zeros (error_r, (mp_limb_t) (n < 0) ? -n : n);
+  if (n == 0)
+    error_r = 0;
+  else
+    count_leading_zeros (error_r, (mp_limb_t) (n < 0) ? -n : n);
   error_r = BITS_PER_MP_LIMB - error_r + 2;
 
   /* for the O(n^(1/2)*M(n)) method, the Taylor series computation of