[src/div_2si.c] Fixed overflow case when n = 0.

[tests/tmul_2exp.c] In the overflow test, check mpfr_div_2si too.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@9596 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 27 insertions, 20 deletions

diff --git a/tests/tmul_2exp.c b/tests/tmul_2exp.c
index 1e4314b38..e11d5d5cf 100644
--- a/tests/tmul_2exp.c
+++ b/tests/tmul_2exp.c
@@ -239,13 +239,14 @@ large0 (void)
   large (MPFR_EMAX_MAX);
 }
 
-/* Cases where mpfr_div_2ui overflows when rounding is like away from zero. */
+/* Cases where mpfr_div_2ui and mpfr_div_2si overflow when rounding
+   is like away from zero. */
 static void
 div_overflow (mpfr_exp_t e)
 {
   mpfr_exp_t emax;
   mpfr_t x, y1, y2;
-  int neg, r;
+  int neg, r, si;
 
   emax = mpfr_get_emax ();
   set_emax (e);
@@ -269,25 +270,31 @@ div_overflow (mpfr_exp_t e)
           flags1 = MPFR_FLAGS_INEXACT;
           if (mpfr_inf_p (y1))
             flags1 |= MPFR_FLAGS_OVERFLOW;
-          mpfr_clear_flags ();
-          inex2 = mpfr_div_2ui (y2, x, 0, (mpfr_rnd_t) r);
-          flags2 = __gmpfr_flags;
-          if (!(mpfr_equal_p (y1, y2) &&
-                SAME_SIGN (inex1, inex2) &&
-                flags1 == flags2))
+          for (si = 0; si <= 1; si++)
             {
-              printf ("Error in div_overflow for %s, x = ",
-                      mpfr_print_rnd_mode ((mpfr_rnd_t) r));
-              mpfr_dump (x);
-              printf ("Expected ");
-              mpfr_dump (y1);
-              printf ("  with inex = %d, flags =", inex1);
-              flags_out (flags1);
-              printf ("Got      ");
-              mpfr_dump (y2);
-              printf ("  with inex = %d, flags =", inex2);
-              flags_out (flags2);
-              exit (1);
+              mpfr_clear_flags ();
+              inex2 = si ?
+                mpfr_div_2si (y2, x, 0, (mpfr_rnd_t) r) :
+                mpfr_div_2ui (y2, x, 0, (mpfr_rnd_t) r);
+              flags2 = __gmpfr_flags;
+              if (!(mpfr_equal_p (y1, y2) &&
+                    SAME_SIGN (inex1, inex2) &&
+                    flags1 == flags2))
+                {
+                  printf ("Error in div_overflow for %s, mpfr_div_2%s, x = ",
+                          mpfr_print_rnd_mode ((mpfr_rnd_t) r),
+                          si ? "si" : "ui");
+                  mpfr_dump (x);
+                  printf ("Expected ");
+                  mpfr_dump (y1);
+                  printf ("  with inex = %d, flags =", inex1);
+                  flags_out (flags1);
+                  printf ("Got      ");
+                  mpfr_dump (y2);
+                  printf ("  with inex = %d, flags =", inex2);
+                  flags_out (flags2);
+                  exit (1);
+                }
             }
         }
       mpfr_neg (x, x, MPFR_RNDN);