glibc/sysdeps/ieee754/dbl-64/s_nextup.c

59 lines
1.6 KiB
C

/* Return the least floating-point number greater than X.
Copyright (C) 2016-2017 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
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
/* Return the least floating-point number greater than X. */
double
__nextup (double x)
{
int32_t hx, ix;
u_int32_t lx;
EXTRACT_WORDS (hx, lx, x);
ix = hx & 0x7fffffff;
if (((ix >= 0x7ff00000) && ((ix - 0x7ff00000) | lx) != 0)) /* x is nan. */
return x + x;
if ((ix | lx) == 0)
return DBL_TRUE_MIN;
if (hx >= 0)
{ /* x > 0. */
if (isinf (x))
return x;
lx += 1;
if (lx == 0)
hx += 1;
}
else
{ /* x < 0. */
if (lx == 0)
hx -= 1;
lx -= 1;
}
INSERT_WORDS (x, hx, lx);
return x;
}
weak_alias (__nextup, nextup)
#ifdef NO_LONG_DOUBLE
strong_alias (__nextup, __nextupl)
weak_alias (__nextup, nextupl)
#endif