Ported bug fix / test of mpfr_set_f to the 2.0 branch.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/branches/mpfr-2-0-2-branch@2762 280ebfd0-de03-0410-8827-d642c229c3f4

2 files changed, 23 insertions, 14 deletions

diff --git a/set_f.c b/set_f.c
index 647ddaafa..e32980b36 100644
--- a/set_f.c
+++ b/set_f.c
@@ -34,22 +34,25 @@ mpfr_set_f (mpfr_ptr y, mpf_srcptr x, mp_rnd_t rnd_mode)
   int inexact, carry = 0;
   TMP_DECL(marker);
 
+  sx = ABS(SIZ(x)); /* number of limbs of the mantissa of x */
+
+  if (sx == 0) /* x is zero */
+    {
+      MPFR_CLEAR_FLAGS (y);
+      MPFR_SET_ZERO(y);
+      MPFR_SET_POS(y);
+      return 0; /* 0 is exact */
+    }
+
   if (SIZ(x) * MPFR_SIGN(y) < 0)
     MPFR_CHANGE_SIGN (y);
 
   MPFR_CLEAR_FLAGS (y);
 
-  sx = ABS(SIZ(x)); /* number of limbs of the mantissa of x */
   sy = 1 + (MPFR_PREC(y) - 1) / BITS_PER_MP_LIMB;
   my = MPFR_MANT(y);
   mx = PTR(x);
 
-  if (sx == 0) /* x is zero */
-    {
-      MPFR_SET_ZERO(y);
-      return 0; /* 0 is exact */
-    }
-
   count_leading_zeros(cnt, mx[sx - 1]);
 
   if (sy <= sx) /* we may have to round even when sy = sx */
diff --git a/tests/tset_f.c b/tests/tset_f.c
index 7e8ae4031..42bff6309 100644
--- a/tests/tset_f.c
+++ b/tests/tset_f.c
@@ -98,13 +98,19 @@ main (void)
   mpf_set_ui (y, 0);
   for(r = 0 ; r < 4 ; r++)
     {
-      inexact = mpfr_set_f(x, y, r);
-      if (MPFR_NOTZERO(x) || MPFR_SIGN(x) < 0 || inexact)
-	{
-	  printf("mpfr_set_f(x,0) failed for %s\n",
-		 mpfr_print_rnd_mode(r));
-	  exit(1);
-	}
+      int i;
+      for (i = -1; i <= 1; i++)
+        {
+          if (i)
+            mpfr_set_si (x, i, GMP_RNDN);
+          inexact = mpfr_set_f (x, y, r);
+          if (!MPFR_IS_ZERO(x) || MPFR_SIGN(x) <= 0 || inexact)
+            {
+              printf ("mpfr_set_f(x,0) failed for %s, i = %d\n",
+                      mpfr_print_rnd_mode (r), i);
+              exit (1);
+            }
+        }
     }
 
   /* coverage test */