Implement 'round', 'roundf', 'roundl' modules.

[gnulib.git] / tests / test-round2.c

diff --git a/tests/test-round2.c b/tests/test-round2.c
new file mode 100644 (file)
index 0000000..1da0d9f
--- /dev/null
+++ b/tests/test-round2.c
@@ -0,0 +1,108 @@
+/* Test of rounding to nearest, breaking ties away from zero.
+   Copyright (C) 2007 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/>.  */
+
+/* Written by Ben Pfaff <blp@gnu.org>, 2007.
+   Heavily based on code by Bruno Haible. */
+
+/* Get the two reference implementations of round under the names
+   round_reference1 and round_reference2.
+   
+   round.c will #include <config.h> for us. */
+#define FLOOR_BASED_ROUND round_reference1
+#define FLOOR_FREE_ROUND round_reference2
+#include "round.c"
+
+#include <math.h>
+#include <float.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "verify.h"
+
+#ifdef USE_LONG_DOUBLE
+# error Long double not supported.
+#elif ! defined USE_FLOAT
+# include "isnan.h"
+# define ISNAN isnan
+# define FUNCTION "round"
+# define DOUBLE_UINT uint64_t
+# define DOUBLE_BITS 64
+# define NUM_HIGHBITS 13
+# define NUM_LOWBITS 4
+#else /* defined USE_FLOAT */
+# include "isnanf.h"
+# define ISNAN isnanf
+# define FUNCTION "roundf"
+# define DOUBLE_UINT uint32_t
+# define DOUBLE_BITS 32
+# define NUM_HIGHBITS 12
+# define NUM_LOWBITS 4
+#endif
+
+/* Test for equality.  */
+static bool
+equal (const char *message, DOUBLE x, DOUBLE y0, DOUBLE y1)
+{
+  if (ISNAN (y0) ? ISNAN (y1) : y0 == y1)
+    return true;
+  else 
+    {
+      fprintf (stderr, "%s: "FUNCTION"(%g(%a)) = %g(%a) or %g(%a)?\n",
+              message, x, x, y0, y0, y1, y1);
+      return false;
+    }
+}
+
+/* Test the function for a given argument.  */
+static bool
+check (DOUBLE x)
+{
+  DOUBLE ref1 = round_reference1 (x);
+  DOUBLE ref2 = round_reference2 (x);
+  DOUBLE result = round (x);
+  
+  /* If the reference implementations disagree, bail out immediately.  */
+  if (!equal ("reference implementations disagree", x, ref1, ref2)) 
+    exit (EXIT_FAILURE);
+
+  /* If the actual implementation is wrong, return an error code.  */
+  return equal ("bad round implementation", x, ref1, result);
+}
+
+int
+main (void)
+{
+  DOUBLE_UINT highbits, lowbits;
+  int error = 0;
+  for (highbits = 0; highbits < (1 << NUM_HIGHBITS); highbits++)
+    for (lowbits = 0; lowbits < (1 << NUM_LOWBITS); lowbits++)
+      {
+       /* Combine highbits and lowbits into a floating-point number,
+          sign-extending the lowbits to DOUBLE_BITS-NUM_HIGHBITS bits.  */
+       union { DOUBLE f; DOUBLE_UINT i; } janus;
+       verify (sizeof janus.f == sizeof janus.i);
+       janus.i = lowbits | (highbits << (DOUBLE_BITS - NUM_HIGHBITS));
+       if (lowbits >> (NUM_LOWBITS - 1))
+         janus.i |= ((DOUBLE_UINT) -1
+                     >> (NUM_LOWBITS + NUM_HIGHBITS)
+                     << NUM_LOWBITS);
+       if (!check (janus.f))
+         error = true;
+      }
+  return (error ? 1 : 0);
+}