glibc/sysdeps/ieee754/ldbl-96/s_llrintl.c
Jakub Jelinek 0ecb606cb6 2.5-18.1
2007-07-12 18:26:36 +00:00

78 lines
2.1 KiB
C

/* Round argument to nearest integral value according to current rounding
direction.
Copyright (C) 1997, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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, 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 two63[2] =
{
9.223372036854775808000000e+18, /* 0x403E, 0x00000000, 0x00000000 */
-9.223372036854775808000000e+18 /* 0xC03E, 0x00000000, 0x00000000 */
};
long long int
__llrintl (long double x)
{
int32_t se,j0;
u_int32_t i0, i1;
long long int result;
volatile long double w;
long double t;
int sx;
GET_LDOUBLE_WORDS (se, i0, i1, x);
sx = (se >> 15) & 1;
j0 = (se & 0x7fff) - 0x3fff;
if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
{
if (j0 < -1)
return 0;
else if (j0 >= 63)
result = (((long long int) i0 << 32) | i1) << (j0 - 63);
else
{
w = two63[sx] + x;
t = w - two63[sx];
GET_LDOUBLE_WORDS (se, i0, i1, t);
j0 = (se & 0x7fff) - 0x3fff;
if (j0 <= 31)
result = i0 >> (31 - j0);
else
result = ((long long int) i0 << (j0 - 31)) | (i1 >> (63 - j0));
}
}
else
{
/* The number is too large. It is left implementation defined
what happens. */
return (long long int) x;
}
return sx ? -result : result;
}
weak_alias (__llrintl, llrintl)