start tests with precision 2 instead of 1

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@1606 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 75 insertions, 8 deletions

diff --git a/tests/tlog2.c b/tests/tlog2.c
index 3d9dc721a..b3b120d61 100644
--- a/tests/tlog2.c
+++ b/tests/tlog2.c
@@ -26,6 +26,49 @@ MA 02111-1307, USA. */
 
 /* tlog2 [prec] [rnd] [0 = no print] */
 
+extern mp_prec_t __mpfr_const_log2_prec;
+void check _PROTO ((mp_prec_t, mp_prec_t));
+
+void
+check (mp_prec_t p0, mp_prec_t p1)
+{
+  mpfr_t x, y, z;
+  mp_rnd_t rnd;
+
+  mpfr_init (x);
+  mpfr_init (y);
+  mpfr_init2 (z, p1 + 10);
+  mpfr_const_log2 (z, GMP_RNDN);
+  __mpfr_const_log2_prec = 1;
+
+  for (; p0<=p1; p0++)
+    {
+      mpfr_set_prec (x, p0);
+      mpfr_set_prec (y, p0);
+      for (rnd = 0; rnd < 4; rnd++)
+        {
+          mpfr_const_log2 (x, rnd);
+          mpfr_set (y, z, rnd);
+          if (mpfr_cmp (x, y) && mpfr_can_round (z, mpfr_get_prec(z), GMP_RNDN,
+                                                 rnd, p0))
+            {
+              fprintf (stderr, "mpfr_const_log2 fails for prec=%u, rnd=%s\n",
+                       (unsigned int) p0, mpfr_print_rnd_mode (rnd));
+              fprintf (stderr, "expected ");
+              mpfr_out_str (stderr, 2, 0, y, GMP_RNDN);
+              fprintf (stderr, "\ngot      ");
+              mpfr_out_str (stderr, 2, 0, x, GMP_RNDN);
+              fprintf (stderr, "\n");
+              exit (1);
+            }
+        }
+    }
+
+  mpfr_clear (x);
+  mpfr_clear (y);
+  mpfr_clear (z);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -35,14 +78,38 @@ main (int argc, char *argv[])
 
   p = (argc>1) ? atoi(argv[1]) : 53;
   rnd = (argc>2) ? atoi(argv[2]) : GMP_RNDZ;
-  mpfr_init2(x, p);
-  mpfr_const_log2(x, rnd);
-  if (argc>=2) {
-    printf("log(2)="); mpfr_out_str(stdout, 10, 0, x, rnd); putchar('\n');
-  }
-  else if (mpfr_get_d(x) != 6.9314718055994530941e-1)  {
-    fprintf(stderr, "mpfr_const_log2 failed for prec=53\n"); exit(1);
-  }
+
+  mpfr_init (x);
+
+  check (2, 1000);
+
+  /* check precision of 2 bits */
+  mpfr_set_prec (x, 2);
+  mpfr_const_log2 (x, GMP_RNDN);
+  if (mpfr_get_d (x) != 0.75)
+    {
+      fprintf (stderr, "mpfr_const_log2 failed for prec=2, rnd=GMP_RNDN\n");
+      fprintf (stderr, "expected 0.75, got %f\n", mpfr_get_d (x));
+      exit (1);
+    }
+
+  if (argc>=2)
+    {
+      mpfr_set_prec (x, p);
+      mpfr_const_log2 (x, rnd);
+      printf ("log(2)=");
+      mpfr_out_str (stdout, 10, 0, x, rnd);
+      putchar('\n');
+    }
+  
+  mpfr_set_prec (x, 53);
+  mpfr_const_log2 (x, rnd);
+  if (mpfr_get_d(x) != 6.9314718055994530941e-1)
+    {
+      fprintf (stderr, "mpfr_const_log2 failed for prec=53\n");
+      exit (1);
+    }
+
   mpfr_clear(x);
 
   return 0;