/* Round to int long double floating-point values.
IBM extended format long double version.
- Copyright (C) 2006, 2007, 2012 Free Software Foundation, Inc.
+ Copyright (C) 2006-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
&& __builtin_isless (__builtin_fabs (xh),
__builtin_inf ()), 1))
{
- double orig_xh;
-
- /* Long double arithmetic, including the canonicalisation below,
- only works in round-to-nearest mode. */
-
- /* Convert the high double to integer. */
- orig_xh = xh;
- hi = ldbl_nearbyint (xh);
-
- /* Subtract integral high part from the value. */
- xh -= hi;
- ldbl_canonicalize (&xh, &xl);
-
- /* Now convert the low double, adjusted for any remainder from the
- high double. */
- lo = ldbl_nearbyint (xh);
-
- /* Adjust the result when the remainder is exactly 0.5. nearbyint
- rounds values halfway between integers to the nearest even
- integer. roundl must round away from zero.
- Also correct cases where nearbyint returns an incorrect value
- for LO. */
- xh -= lo;
- ldbl_canonicalize (&xh, &xl);
- if (xh == 0.5)
+ hi = __round (xh);
+ if (hi != xh)
{
- if (xl > 0.0 || (xl == 0.0 && orig_xh > 0.0))
- lo += 1.0;
+ /* The high part is not an integer; the low part only
+ affects the result if the high part is exactly half way
+ between two integers and the low part is nonzero with the
+ opposite sign. */
+ if (fabs (hi - xh) == 0.5)
+ {
+ if (xh > 0 && xl < 0)
+ xh = hi - 1;
+ else if (xh < 0 && xl > 0)
+ xh = hi + 1;
+ else
+ xh = hi;
+ }
+ else
+ xh = hi;
+ xl = 0;
}
- else if (-xh == 0.5)
+ else
{
- if (xl < 0.0 || (xl == 0.0 && orig_xh < 0.0))
- lo -= 1.0;
+ /* The high part is a nonzero integer. */
+ lo = __round (xl);
+ if (fabs (lo - xl) == 0.5)
+ {
+ if (xh > 0 && xl < 0)
+ xl = lo + 1;
+ else if (xh < 0 && lo > 0)
+ xl = lo - 1;
+ else
+ xl = lo;
+ }
+ else
+ xl = lo;
+ xh = hi;
+ ldbl_canonicalize_int (&xh, &xl);
}
-
- /* Ensure the final value is canonical. In certain cases,
- rounding causes hi,lo calculated so far to be non-canonical. */
- xh = hi;
- xl = lo;
- ldbl_canonicalize (&xh, &xl);
}
+ else
+ /* Quiet signaling NaN arguments. */
+ xh += xh;
return ldbl_pack (xh, xl);
}