glibc/sysdeps/ieee754/ldbl-96/s_nextupl.c

87 lines
2.2 KiB
C

/* Return the least floating-point number greater than X.
Copyright (C) 2016-2024 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
<https://www.gnu.org/licenses/>. */
#include <float.h>
#include <math.h>
#include <math_private.h>
#include <libm-alias-ldouble.h>
/* Return the least floating-point number greater than X. */
long double
__nextupl (long double x)
{
uint32_t hx, ix;
uint32_t lx;
int32_t esx;
GET_LDOUBLE_WORDS (esx, hx, lx, x);
ix = esx & 0x7fff;
if (((ix == 0x7fff) && (((hx & 0x7fffffff) | lx) != 0))) /* x is nan. */
return x + x;
if ((ix | hx | lx) == 0)
return LDBL_TRUE_MIN;
if (esx >= 0)
{ /* x > 0. */
if (isinf (x))
return x;
lx += 1;
if (lx == 0)
{
hx += 1;
#if LDBL_MIN_EXP == -16381
if (hx == 0 || (esx == 0 && hx == 0x80000000))
#else
if (hx == 0)
#endif
{
esx += 1;
hx |= 0x80000000;
}
}
}
else
{ /* x < 0. */
if (lx == 0)
{
#if LDBL_MIN_EXP == -16381
if (hx <= 0x80000000 && esx != 0xffff8000)
{
esx -= 1;
hx = hx - 1;
if ((esx & 0x7fff) > 0)
hx |= 0x80000000;
}
else
hx -= 1;
#else
if (ix != 0 && hx == 0x80000000)
hx = 0;
if (hx == 0)
esx -= 1;
hx -= 1;
#endif
}
lx -= 1;
}
SET_LDOUBLE_WORDS (x, esx, hx, lx);
return x;
}
libm_alias_ldouble (__nextup, nextup)