logb tests: More tests.

* tests/test-logb.h: New file, based on tests/test-logb.c and
tests/test-frexp.h.
* tests/test-logb.c: Include minus-zero.h, test-logb.h.
(main): Just invoke test_function.
* modules/logb-tests (Files): Add tests/test-logb.h,
tests/minus-zero.h, tests/randomd.c.
(Makefile.am): Add randomd.c to test_logb_SOURCES.

2 files changed, 163 insertions, 26 deletions

diff --git a/tests/test-logb.c b/tests/test-logb.c
index 34ad3311b9..bef0ec5417 100644
--- a/tests/test-logb.c
+++ b/tests/test-logb.c
@@ -25,38 +25,30 @@ SIGNATURE_CHECK (logb, double, (double));
 
 #include <float.h>
 
+#include "minus-zero.h"
 #include "macros.h"
 
-volatile double x;
-double y;
+#define DOUBLE double
+/* The use of 'volatile' guarantees that excess precision bits are dropped
+   when dealing with denormalized numbers.  It is necessary on x86 systems
+   where double-floats are not IEEE compliant by default, to avoid that the
+   results become platform and compiler option dependent.  'volatile' is a
+   portable alternative to gcc's -ffloat-store option.  */
+#define VOLATILE volatile
+#define HUGEVAL HUGE_VAL
+#define L_(literal) literal
+#define MINUS_ZERO minus_zerod
+#define MAX_EXP DBL_MAX_EXP
+#define MIN_EXP DBL_MIN_EXP
+#define MIN_NORMAL_EXP DBL_MIN_EXP
+#define LOGB logb
+#define RANDOM randomd
+#include "test-logb.h"
 
 int
 main ()
 {
-  /* Some particular values.  */
-  x = 0.6;
-  y = logb (x);
-  ASSERT (y == -1.0);
-
-  x = 1.2;
-  y = logb (x);
-  ASSERT (y == 0.0);
-
-  x = 2.1;
-  y = logb (x);
-  ASSERT (y == 1.0);
-
-  x = 3.9;
-  y = logb (x);
-  ASSERT (y == 1.0);
-
-  x = 4.0;
-  y = logb (x);
-  ASSERT (y == (FLT_RADIX == 2 ? 2.0 : 1.0));
-
-  x = 0.25;
-  y = logb (x);
-  ASSERT (y == (FLT_RADIX == 2 ? -2.0 : -1.0));
+  test_function ();
 
   return 0;
 }
diff --git a/tests/test-logb.h b/tests/test-logb.h
new file mode 100644
index 0000000000..404e7dd6a8
--- /dev/null
+++ b/tests/test-logb.h
@@ -0,0 +1,145 @@
+/* Test of logb*() function family.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+static DOUBLE
+my_ldexp (DOUBLE x, int d)
+{
+  for (; d > 0; d--)
+    x *= L_(2.0);
+  for (; d < 0; d++)
+    x *= L_(0.5);
+  return x;
+}
+
+static void
+test_function (void)
+{
+  int i;
+  VOLATILE DOUBLE x;
+  DOUBLE y;
+
+  /* Some particular values.  */
+  x = L_(0.6);
+  y = LOGB (x);
+  ASSERT (y == - L_(1.0));
+
+  x = L_(1.2);
+  y = LOGB (x);
+  ASSERT (y == L_(0.0));
+
+  x = L_(2.1);
+  y = LOGB (x);
+  ASSERT (y == L_(1.0));
+
+  x = L_(3.9);
+  y = LOGB (x);
+  ASSERT (y == L_(1.0));
+
+  x = L_(4.0);
+  y = LOGB (x);
+  ASSERT (y == (FLT_RADIX == 2 ? L_(2.0) : L_(1.0)));
+
+  x = L_(0.25);
+  y = LOGB (x);
+  ASSERT (y == (FLT_RADIX == 2 ? - L_(2.0) : - L_(1.0)));
+
+  /* Zero.  */
+  ASSERT (LOGB (L_(0.0)) == - HUGEVAL);
+  ASSERT (LOGB (MINUS_ZERO) == - HUGEVAL);
+
+  /* From here on, this test assumes FLT_RADIX == 2.  */
+
+  for (i = 1, x = L_(1.0); i <= MAX_EXP; i++, x *= L_(2.0))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (i = 1, x = L_(1.0); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+
+  for (i = 1, x = - L_(1.0); i <= MAX_EXP; i++, x *= L_(2.0))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (i = 1, x = - L_(1.0); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (; i >= MIN_EXP - 100 && x < L_(0.0); i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+
+  for (i = 1, x = L_(1.01); i <= MAX_EXP; i++, x *= L_(2.0))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (i = 1, x = L_(1.01); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+
+  for (i = 1, x = L_(1.73205); i <= MAX_EXP; i++, x *= L_(2.0))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (i = 1, x = L_(1.73205); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1));
+    }
+  for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5))
+    {
+      y = LOGB (x);
+      ASSERT (y == (DOUBLE)(i - 1) || y == (DOUBLE)i);
+    }
+
+  /* Randomized tests.  */
+  for (i = 0; i < SIZEOF (RANDOM); i++)
+    {
+      x = L_(20.0) * RANDOM[i] - L_(10.0); /* -10.0 <= x <= 10.0 */
+      if (x != L_(0.0))
+        {
+          DOUBLE abs_x = (x < L_(0.0) ? - x : x);
+          y = LOGB (x);
+          ASSERT (y == (DOUBLE) (int) y);
+          ASSERT (abs_x >= my_ldexp (L_(1.0), (int) y));
+          ASSERT (abs_x < my_ldexp (L_(1.0), (int) y + 1));
+        }
+    }
+}
+
+volatile DOUBLE x;
+DOUBLE y;