glibc/sysdeps/ieee754/ldbl-128/s_lrintl.c

89 lines
2.4 KiB
C

/* Round argument to nearest integral value according to current rounding
direction.
Copyright (C) 1997-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
Jakub Jelinek <jj@ultra.linux.cz>, 1999.
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>
static const long double two112[2] =
{
5.19229685853482762853049632922009600E+33L, /* 0x406F000000000000, 0 */
-5.19229685853482762853049632922009600E+33L /* 0xC06F000000000000, 0 */
};
long int
__lrintl (long double x)
{
int32_t j0;
u_int64_t i0,i1;
volatile long double w;
long double t;
long int result;
int sx;
GET_LDOUBLE_WORDS64 (i0, i1, x);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
sx = i0 >> 63;
i0 &= 0x0000ffffffffffffLL;
i0 |= 0x0001000000000000LL;
if (j0 < 48)
{
w = two112[sx] + x;
t = w - two112[sx];
GET_LDOUBLE_WORDS64 (i0, i1, t);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
i0 &= 0x0000ffffffffffffLL;
i0 |= 0x0001000000000000LL;
result = (j0 < 0 ? 0 : i0 >> (48 - j0));
}
else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
{
if (j0 >= 112)
result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
else
{
w = two112[sx] + x;
t = w - two112[sx];
GET_LDOUBLE_WORDS64 (i0, i1, t);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
i0 &= 0x0000ffffffffffffLL;
i0 |= 0x0001000000000000LL;
if (j0 == 48)
result = (long int) i0;
else
result = ((long int) i0 << (j0 - 48)) | (i1 >> (112 - j0));
}
}
else
{
/* The number is too large. It is left implementation defined
what happens. */
return (long int) x;
}
return sx ? -result : result;
}
weak_alias (__lrintl, lrintl)