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-rw-r--r--tests/test-printf-frexp.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/tests/test-printf-frexp.c b/tests/test-printf-frexp.c
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+/* Test of splitting a double into fraction and mantissa.
+ Copyright (C) 2007-2008 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 Bruno Haible <bruno@clisp.org>, 2007. */
+
+#include <config.h>
+
+#include "printf-frexp.h"
+
+#include <float.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define ASSERT(expr) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+ fflush (stderr); \
+ abort (); \
+ } \
+ } \
+ while (0)
+
+static double
+my_ldexp (double x, int d)
+{
+ for (; d > 0; d--)
+ x *= 2.0;
+ for (; d < 0; d++)
+ x *= 0.5;
+ return x;
+}
+
+int
+main ()
+{
+ int i;
+ /* 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. */
+ volatile double x;
+
+ for (i = 1, x = 1.0; i <= DBL_MAX_EXP; i++, x *= 2.0)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == i - 1);
+ ASSERT (mantissa == 1.0);
+ }
+ for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == i - 1);
+ ASSERT (mantissa == 1.0);
+ }
+ for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == DBL_MIN_EXP - 1);
+ ASSERT (mantissa == my_ldexp (1.0, i - DBL_MIN_EXP));
+ }
+
+ for (i = 1, x = 1.01; i <= DBL_MAX_EXP; i++, x *= 2.0)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == i - 1);
+ ASSERT (mantissa == 1.01);
+ }
+ for (i = 1, x = 1.01; i >= DBL_MIN_EXP; i--, x *= 0.5)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == i - 1);
+ ASSERT (mantissa == 1.01);
+ }
+ for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == DBL_MIN_EXP - 1);
+ ASSERT (mantissa >= my_ldexp (1.0, i - DBL_MIN_EXP));
+ ASSERT (mantissa <= my_ldexp (2.0, i - DBL_MIN_EXP));
+ ASSERT (mantissa == my_ldexp (x, - exp));
+ }
+
+ for (i = 1, x = 1.73205; i <= DBL_MAX_EXP; i++, x *= 2.0)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == i - 1);
+ ASSERT (mantissa == 1.73205);
+ }
+ for (i = 1, x = 1.73205; i >= DBL_MIN_EXP; i--, x *= 0.5)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == i - 1);
+ ASSERT (mantissa == 1.73205);
+ }
+ for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5)
+ {
+ int exp = -9999;
+ double mantissa = printf_frexp (x, &exp);
+ ASSERT (exp == DBL_MIN_EXP - 1);
+ ASSERT (mantissa >= my_ldexp (1.0, i - DBL_MIN_EXP));
+ ASSERT (mantissa <= my_ldexp (2.0, i - DBL_MIN_EXP));
+ ASSERT (mantissa == my_ldexp (x, - exp));
+ }
+
+ return 0;
+}