get_f.c: remove dead code (x and z always have the same number of limbs).

tests/tget_f.c: Add tests with every rounding mode, add tests with random values.


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@6173 280ebfd0-de03-0410-8827-d642c229c3f4

2 files changed, 93 insertions, 103 deletions

diff --git a/get_f.c b/get_f.c
index cb795d98e..41aa03a71 100644
--- a/get_f.c
+++ b/get_f.c
@@ -113,31 +113,30 @@ mpfr_get_f (mpf_ptr x, mpfr_srcptr y, mp_rnd_t rnd_mode)
   else /* we have to round to precx - sh bits */
     {
       mpfr_t z;
-      mp_size_t sz, ds;
+      mp_size_t sz;
 
-      /* Recall that precx = (mp_prec_t) sx * BITS_PER_MP_LIMB */
+      /* Recall that precx = (mp_prec_t) sx * BITS_PER_MP_LIMB, thus removing
+         sh bits (sh < BITS_PER_MP_LIMBS) won't reduce the number of limbs. */
       mpfr_init2 (z, precx - sh);
       sz = MPFR_LIMB_SIZE (z);
+      MPFR_ASSERTN (sx == sz);
+
       inex = mpfr_set (z, y, rnd_mode);
       /* warning, sh may change due to rounding, but then z is a power of two,
          thus we can safely ignore its last bit which is 0 */
       sh = MPFR_GET_EXP(z) % BITS_PER_MP_LIMB;
       sh = sh <= 0 ? - sh : BITS_PER_MP_LIMB - sh;
-      MPFR_ASSERTD (sx >= sz);
-      ds = sx - sz;
-      MPFR_ASSERTD (sh >= 0 && ds <= 1);
+      MPFR_ASSERTD (sh >= 0);
       if (sh != 0)
         {
           mp_limb_t out;
-          out = mpn_rshift (xp + ds, MPFR_MANT(z), sz, sh);
+          out = mpn_rshift (xp, MPFR_MANT(z), sz, sh);
           /* If sh hasn't changed, it is the number of the non-significant
              bits in the lowest limb of z. Therefore out == 0. */
           MPFR_ASSERTD (out == 0);
         }
       else
-        MPN_COPY (xp + ds, MPFR_MANT(z), sz);
-      if (ds != 0)
-        xp[0] = 0;
+        MPN_COPY (xp, MPFR_MANT(z), sz);
       EXP(x) = (MPFR_GET_EXP(z) + sh) / BITS_PER_MP_LIMB;
       mpfr_clear (z);
     }
diff --git a/tests/tget_f.c b/tests/tget_f.c
index 03929f560..f521660a3 100644
--- a/tests/tget_f.c
+++ b/tests/tget_f.c
@@ -169,104 +169,95 @@ special_test (void)
 static void
 ternary_test (void)
 {
-  int inex;
+  int prec;
+  mpfr_rnd_t rnd; 
+  int inex, expected_inex;
   mpf_t x;
   mpfr_t y;
 
-  mpf_init2 (x, BITS_PER_MP_LIMB);
-  mpfr_init2 (y, 2 * BITS_PER_MP_LIMB);
-
-  /* y == 1 */
-  mpfr_set_ui (y, 1, MPFR_RNDN);
-
-  inex = mpfr_get_f (x, y, MPFR_RNDU);
-  if (inex != 0 || mpfr_cmp_f (y, x) !=0)
-    {
-      printf ("Error in mpfr_get_f (x, y, MPFR_RNDU)\n");
-      printf ("x = ");
-      mpf_dump (x);
-      printf ("y = ");
-      mpfr_dump (y);
-      if (inex != 0)
-        printf ("got ternary value = %+d, expected: 0\n", inex);
-
-      exit (1);
-    }
+  mpf_init2 (x, 256);
+  mpfr_init2 (y, 256);
 
-  inex = mpfr_get_f (x, y, MPFR_RNDD);
-  if (inex != 0 || mpfr_cmp_f (y, x) !=0)
+  for (prec = 2; prec <= 256; prec++)
     {
-      printf ("Error in mpfr_get_f (x, y, MPFR_RNDD)\n");
-      printf ("x = ");
-      mpf_dump (x);
-      printf ("y = ");
-      mpfr_dump (y);
-      if (inex != 0)
-        printf ("got ternary value = %+d, expected: 0\n", inex);
-
-      exit (1);
-    }
-
-  /* y == 1 + epsilon */
-  mpfr_nextabove (y);
-
-  inex = mpfr_get_f (x, y, MPFR_RNDU);
-  if (inex <= 0 || mpfr_cmp_f (y, x) >=0)
-    {
-      printf ("Error in mpfr_get_f (x, y, MPFR_RNDU)\n");
-      printf ("x = ");
-      mpf_dump (x);
-      printf ("y = ");
-      mpfr_dump (y);
-      if (inex <= 0)
-        printf ("got ternary value = %+d, expected: +1\n", inex);
-
-      exit (1);
-    }
 
-  inex = mpfr_get_f (x, y, MPFR_RNDD);
-  if (inex >= 0 || mpfr_cmp_f (y, x) <=0)
-    {
-      printf ("Error in mpfr_get_f (x, y, MPFR_RNDD)\n");
-      printf ("x = ");
-      mpf_dump (x);
-      printf ("y = ");
-      mpfr_dump (y);
-      if (inex >= 0)
-        printf ("got ternary value = %+d, expected: -1\n", inex);
-
-      exit (1);
-    }
-
-  /* y == -1 - epsilon */
-  mpfr_neg (y, y, MPFR_RNDN);
-
-  inex = mpfr_get_f (x, y, MPFR_RNDU);
-  if (inex <= 0 || mpfr_cmp_f (y, x) >=0)
-    {
-      printf ("Error in mpfr_get_f (x, y, MPFR_RNDU)\n");
-      printf ("x = ");
-      mpf_dump (x);
-      printf ("y = ");
-      mpfr_dump (y);
-      if (inex <= 0)
-        printf ("got ternary value = %+d, expected: +1\n", inex);
-
-      exit (1);
-    }
-
-  inex = mpfr_get_f (x, y, MPFR_RNDD);
-  if (inex >= 0 || mpfr_cmp_f (y, x) <=0)
-    {
-      printf ("Error in mpfr_get_f (x, y, MPFR_RNDD)\n");
-      printf ("x = ");
-      mpf_dump (x);
-      printf ("y = ");
-      mpfr_dump (y);
-      if (inex >= 0)
-        printf ("got ternary value = %+d, expected: -1\n", inex);
-
-      exit (1);
+      mpf_set_prec (x, prec);
+      mpfr_set_prec (y, PREC (x) * BITS_PER_MP_LIMB + 1);
+
+      /* y == 1 */
+      mpfr_set_ui_2exp (y, 1, prec, MPFR_RNDN);
+
+      RND_LOOP (rnd)
+      {
+        inex = mpfr_get_f (x, y, rnd);
+
+        if (inex != 0 || mpfr_cmp_f (y, x) !=0)
+          {
+            printf ("Error in mpfr_get_f (x, y, %s)\nx = ", 
+                    mpfr_print_rnd_mode (rnd));
+            mpf_out_str (stdout, 2, 0, x);
+            printf ("\ny = ");
+            mpfr_dump (y);
+            if (inex != 0)
+              printf ("got ternary value = %+d, expected: 0\n", inex);
+
+            exit (1);
+          }
+      }
+
+      /* y == 1 + epsilon */
+      mpfr_nextbelow (y);
+
+      RND_LOOP (rnd)
+      {
+        switch (rnd)
+          {
+          case MPFR_RNDU: case MPFR_RNDA:
+          case MPFR_RNDN:
+            expected_inex = +1;
+            break;
+          default :
+            expected_inex = -1;
+          }
+
+        inex = mpfr_get_f (x, y, rnd);
+
+        if (! SAME_SIGN (expected_inex, inex)
+            || SAME_SIGN (expected_inex, mpfr_cmp_f (y, x)))
+          {
+            printf ("Error in mpfr_get_f (x, y, %s)\nx = ",
+                    mpfr_print_rnd_mode (rnd));
+            mpf_out_str (stdout, 2, 0, x);
+            printf ("\ny = ");
+            mpfr_dump (y);
+            if (! SAME_SIGN (expected_inex, inex))
+              printf ("got ternary value = %+d, expected: %+d\n",
+                      inex, expected_inex);
+
+            exit (1);
+          }
+      }
+
+      /* y == positive random float */
+      mpfr_random2 (y, MPFR_LIMB_SIZE (y), 1024, RANDS);
+
+      RND_LOOP (rnd)
+      {
+        inex = mpfr_get_f (x, y, rnd);
+
+        if (! SAME_SIGN (inex, -mpfr_cmp_f (y, x)))
+          {
+            printf ("Error in mpfr_get_f (x, y, %s)\nx = ",
+                    mpfr_print_rnd_mode (rnd));
+            mpf_out_str (stdout, 2, 0, x);
+            printf ("\ny = ");
+            mpfr_dump (y);
+            printf ("got ternary value = %+d, expected: %+d\n",
+                    inex, -mpfr_cmp_f (y, x));
+
+            exit (1);
+          }
+      }
     }
 
   mpf_clear (x);
@@ -349,7 +340,7 @@ main (void)
           mpfr_dump (y);
           printf ("x=");
           mpf_div_2exp (x, x, e);
-          mpf_dump (x);
+          mpf_out_str (stdout, 2, 0, x);
           exit (1);
         }
 
@@ -365,7 +356,7 @@ main (void)
           mpfr_dump (y);
           printf ("x=");
           mpf_mul_2exp (x, x, e);
-          mpf_dump (x);
+          mpf_out_str (stdout, 2, 0, x);
           exit (1);
         }
     }