deal with overflow/underflow in mpfr_div

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2734 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 13 insertions, 1 deletions

diff --git a/div.c b/div.c
index 4f5c9db5e..1ccfae8f7 100644
--- a/div.c
+++ b/div.c
@@ -444,7 +444,19 @@ mpfr_div (mpfr_ptr q, mpfr_srcptr u, mpfr_srcptr v, mp_rnd_t rnd_mode)
   TMP_FREE (marker);
 
   MPFR_MANT(q)[0] &= ~((MPFR_LIMB_ONE << rw) - MPFR_LIMB_ONE);
-  MPFR_SET_EXP (q, qexp);
+  MPFR_EXP(q) = qexp;
+
+  /* check for underflow/overflow */
+
+  if (MPFR_UNLIKELY(qexp > __gmpfr_emax))
+    inex = mpfr_set_overflow (q, rnd_mode, sign_quotient);
+  else if (MPFR_UNLIKELY(qexp < __gmpfr_emin))
+    {
+      if (rnd_mode == GMP_RNDN && ((qexp < __gmpfr_emin - 1) ||
+                                   (inex == 0 && mpfr_powerof2_raw (q))))
+        rnd_mode = GMP_RNDZ;
+      inex = mpfr_set_underflow (q, rnd_mode, sign_quotient);
+    }
 
   MPFR_RET(inex);
 }