99 lines
2.4 KiB
C
99 lines
2.4 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 two52[2] =
|
|
{
|
|
4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
|
|
-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
|
|
};
|
|
|
|
|
|
long long int
|
|
__llrint (double x)
|
|
{
|
|
int32_t j0;
|
|
u_int32_t i1, i0;
|
|
long long int result;
|
|
volatile double w;
|
|
double t;
|
|
int sx;
|
|
|
|
EXTRACT_WORDS (i0, i1, x);
|
|
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
|
|
sx = i0 >> 31;
|
|
i0 &= 0xfffff;
|
|
i0 |= 0x100000;
|
|
|
|
if (j0 < 20)
|
|
{
|
|
if (j0 < -1)
|
|
return 0;
|
|
else
|
|
{
|
|
w = two52[sx] + x;
|
|
t = w - two52[sx];
|
|
EXTRACT_WORDS (i0, i1, t);
|
|
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
|
|
i0 &= 0xfffff;
|
|
i0 |= 0x100000;
|
|
|
|
result = i0 >> (20 - j0);
|
|
}
|
|
}
|
|
else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
|
|
{
|
|
if (j0 >= 52)
|
|
result = (((long long int) i0 << 32) | i1) << (j0 - 52);
|
|
else
|
|
{
|
|
w = two52[sx] + x;
|
|
t = w - two52[sx];
|
|
EXTRACT_WORDS (i0, i1, t);
|
|
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
|
|
i0 &= 0xfffff;
|
|
i0 |= 0x100000;
|
|
|
|
if (j0 == 20)
|
|
result = (long long int) i0;
|
|
else
|
|
result = ((long long int) i0 << (j0 - 20)) | (i1 >> (52 - 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 (__llrint, llrint)
|
|
#ifdef NO_LONG_DOUBLE
|
|
strong_alias (__llrint, __llrintl)
|
|
weak_alias (__llrint, llrintl)
|
|
#endif
|