[src/compound.c] fixed case n < 0 and underflow

[tests/tcompound.c] added corresponding non-regression tests


git-svn-id: https://scm.gforge.inria.fr/anonscm/svn/mpfr/trunk@14360 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/tcompound.c b/tests/tcompound.c
index 7c41af0aa..5580ed043 100644
--- a/tests/tcompound.c
+++ b/tests/tcompound.c
@@ -174,6 +174,40 @@ check_ieee754 (void)
       exit (1);
     }
 
+  /* test for negative n */
+  i = -1;
+  while (1)
+    {
+      mpfr_set_si_2exp (x, -1, -1, MPFR_RNDN); /* x = -0.5 */
+      mpfr_compound (y, x, i, MPFR_RNDN);
+      mpfr_set_ui_2exp (x, 1, -i, MPFR_RNDN);
+      if (!mpfr_equal_p (y, x))
+        {
+          printf ("Error for compound(-0.5,%ld)\n", i);
+          printf ("expected "); mpfr_dump (x);
+          printf ("got      "); mpfr_dump (y);
+          exit (1);
+        }
+      if (i == -2147483647) /* largest possible value on 32-bit machine */
+        break;
+      i = 2 * i - 1;
+    }
+
+#if GMP_NUMB_BITS >= 64 || MPFR_PREC_BITS >= 64
+  /* then 64-bit constants are supported */
+  i = 4994322635099777669L;
+  mpfr_set_ui (x, 1, MPFR_RNDN);
+  mpfr_compound (y, x, -i, MPFR_RNDN);
+  mpfr_set_si_2exp (x, 1, -i, MPFR_RNDN);
+  if (!mpfr_equal_p (y, x))
+    {
+      printf ("Error for compound(1,%ld)\n", i);
+      printf ("expected "); mpfr_dump (x);
+      printf ("got      "); mpfr_dump (y);
+      exit (1);
+    }
+#endif
+
   mpfr_clear (x);
   mpfr_clear (y);
 }