glibc/sysdeps/ieee754/ldbl-128/s_lrintl.c
Ulrich Drepper abfbdde177 Update.
1999-07-14 00:54:57 +00:00

92 lines
2.5 KiB
C

/* Round argument to nearest integral value according to current rounding
direction.
Copyright (C) 1997, 1999 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#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)
{
if (j0 < -1)
return 0;
else
{
w = two112[sx] + x;
t = w - two112[sx];
GET_LDOUBLE_WORDS64 (i0, i1, x);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
i0 &= 0x0000ffffffffffffLL;
i0 |= 0x0001000000000000LL;
result = 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, x);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
i0 &= 0x0000ffffffffffffLL;
i0 |= 0x0001000000000000LL;
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)