/* Test of rounding towards zero.
- Copyright (C) 2007-2010 Free Software Foundation, Inc.
+ Copyright (C) 2007-2012 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
/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
+/* When this test fails on some platform, build it together with the gnulib
+ module 'fprintf-posix' for optimal debugging output. */
+
#include <config.h>
#include <math.h>
#include <stdio.h>
#include "isnanf-nolibm.h"
+#include "minus-zero.h"
#include "macros.h"
+/* MSVC with option -fp:strict refuses to compile constant initializers that
+ contain floating-point operations. Pacify this compiler. */
+#ifdef _MSC_VER
+# pragma fenv_access (off)
+#endif
+
/* The reference implementation, taken from lib/trunc.c. */
#define MANT_DIG FLT_MANT_DIG
#define L_(literal) literal##f
+/* -0.0. See minus-zero.h. */
+#define MINUS_ZERO minus_zerof
+
/* 2^(MANT_DIG-1). */
static const DOUBLE TWO_MANT_DIG =
/* Assume MANT_DIG <= 5 * 31.
if (z > L_(0.0))
{
+ /* For 0 < x < 1, return +0.0 even if the current rounding mode is
+ FE_DOWNWARD. */
+ if (z < L_(1.0))
+ z = L_(0.0);
/* Avoid rounding errors for values near 2^k, where k >= MANT_DIG-1. */
- if (z < TWO_MANT_DIG)
+ else if (z < TWO_MANT_DIG)
{
/* Round to the next integer (nearest or up or down, doesn't matter). */
z += TWO_MANT_DIG;
}
else if (z < L_(0.0))
{
+ /* For -1 < x < 0, return -0.0 regardless of the current rounding
+ mode. */
+ if (z > L_(-1.0))
+ z = MINUS_ZERO;
/* Avoid rounding errors for values near -2^k, where k >= MANT_DIG-1. */
- if (z > - TWO_MANT_DIG)
+ else if (z > - TWO_MANT_DIG)
{
/* Round to the next integer (nearest or up or down, doesn't matter). */
z -= TWO_MANT_DIG;
return 0;
else
{
+#if GNULIB_TEST_FPRINTF_POSIX
fprintf (stderr, "truncf %g(%a) = %g(%a) or %g(%a)?\n",
x, x, reference, reference, result, result);
+#endif
return 1;
}
}