/* Round toward nearest, breaking ties away from zero.
- Copyright (C) 2007 Free Software Foundation, Inc.
+ Copyright (C) 2007, 2010-2011 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
#include <config.h>
-#include <float.h>
+/* Specification. */
#include <math.h>
+#include <float.h>
+
+#undef MIN
+
#ifdef USE_LONG_DOUBLE
# define ROUND roundl
# define FLOOR floorl
# define CEIL ceill
# define DOUBLE long double
# define MANT_DIG LDBL_MANT_DIG
+# define MIN LDBL_MIN
# define L_(literal) literal##L
# define HAVE_FLOOR_AND_CEIL HAVE_FLOORL_AND_CEILL
#elif ! defined USE_FLOAT
# define CEIL ceil
# define DOUBLE double
# define MANT_DIG DBL_MANT_DIG
+# define MIN DBL_MIN
# define L_(literal) literal
# define HAVE_FLOOR_AND_CEIL 1
#else /* defined USE_FLOAT */
# define CEIL ceilf
# define DOUBLE float
# define MANT_DIG FLT_MANT_DIG
+# define MIN FLT_MIN
# define L_(literal) literal##f
# define HAVE_FLOOR_AND_CEIL HAVE_FLOORF_AND_CEILF
#endif
+/* -0.0. See minus-zero.h. */
+#if defined __hpux || defined __sgi || defined __ICC
+# define MINUS_ZERO (-MIN * MIN)
+#else
+# define MINUS_ZERO L_(-0.0)
+#endif
+
/* If we're being included from test-round2[f].c, it already defined names for
our round implementations. Otherwise, pick the preferred implementation for
this machine. */
{
/* Avoid rounding error for x = 0.5 - 2^(-MANT_DIG-1). */
if (z < L_(0.5))
- z = L_(0.0);
+ z = L_(0.0);
/* Avoid rounding errors for values near 2^k, where k >= MANT_DIG-1. */
else if (z < TWO_MANT_DIG)
- {
- /* Add 0.5 to the absolute value. */
- y = z += L_(0.5);
- /* Round to the next integer (nearest or up or down, doesn't
+ {
+ /* Add 0.5 to the absolute value. */
+ y = z += L_(0.5);
+ /* Round to the next integer (nearest or up or down, doesn't
matter). */
- z += TWO_MANT_DIG;
- z -= TWO_MANT_DIG;
- /* Enforce rounding down. */
- if (z > y)
- z -= L_(1.0);
- }
+ z += TWO_MANT_DIG;
+ z -= TWO_MANT_DIG;
+ /* Enforce rounding down. */
+ if (z > y)
+ z -= L_(1.0);
+ }
}
else if (z < L_(0.0))
{
/* Avoid rounding error for x = -(0.5 - 2^(-MANT_DIG-1)). */
if (z > - L_(0.5))
- z = L_(0.0);
+ z = MINUS_ZERO;
/* Avoid rounding errors for values near -2^k, where k >= MANT_DIG-1. */
else if (z > -TWO_MANT_DIG)
- {
- /* Add 0.5 to the absolute value. */
- y = z -= L_(0.5);
- /* Round to the next integer (nearest or up or down, doesn't
+ {
+ /* Add 0.5 to the absolute value. */
+ y = z -= L_(0.5);
+ /* Round to the next integer (nearest or up or down, doesn't
matter). */
- z -= TWO_MANT_DIG;
- z += TWO_MANT_DIG;
- /* Enforce rounding up. */
- if (z < y)
- z += L_(1.0);
- }
+ z -= TWO_MANT_DIG;
+ z += TWO_MANT_DIG;
+ /* Enforce rounding up. */
+ if (z < y)
+ z += L_(1.0);
+ }
}
return z;
}