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/* Round double value to long long int.
Copyright (C) 1997-2017 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
<http://www.gnu.org/licenses/>. */
#include <limits.h>
#include <math.h>
#include <math_ldbl_opt.h>
#include <math_private.h>
#include <stdint.h>
/* Round to the nearest integer, with values exactly on a 0.5 boundary
rounded away from zero, regardless of the current rounding mode.
If (long long)x, when x is out of range of a long long, clips at
LLONG_MAX or LLONG_MIN, then this implementation also clips. */
long long int
__llround (double x)
{
long long xr;
if (HAVE_PPC_FCTIDZ)
xr = (long long) x;
else
{
/* Avoid incorrect exceptions from libgcc conversions (as of GCC
5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>. */
if (fabs (x) < 0x1p31)
xr = (long long int) (long int) x;
else
{
uint64_t i0;
EXTRACT_WORDS64 (i0, x);
int exponent = ((i0 >> 52) & 0x7ff) - 0x3ff;
if (exponent < 63)
{
unsigned long long int mant
= (i0 & ((1ULL << 52) - 1)) | (1ULL << 52);
if (exponent < 52)
/* llround is not required to raise "inexact". */
mant >>= 52 - exponent;
else
mant <<= exponent - 52;
xr = (long long int) ((i0 & (1ULL << 63)) != 0 ? -mant : mant);
}
else if (x == (double) LLONG_MIN)
xr = LLONG_MIN;
else
xr = (long long int) (long int) x << 32;
}
}
/* Avoid spurious "inexact" converting LLONG_MAX to double, and from
subtraction when the result is out of range, by returning early
for arguments large enough that no rounding is needed. */
if (!(fabs (x) < 0x1p52))
return xr;
double xrf = (double) xr;
if (x >= 0.0)
{
if (x - xrf >= 0.5)
xr += (long long) ((unsigned long long) xr + 1) > 0;
}
else
{
if (xrf - x >= 0.5)
xr -= (long long) ((unsigned long long) xr - 1) < 0;
}
return xr;
}
weak_alias (__llround, llround)
#ifdef NO_LONG_DOUBLE
strong_alias (__llround, __llroundl)
weak_alias (__llround, llroundl)
#endif
#if LONG_DOUBLE_COMPAT (libm, GLIBC_2_1)
compat_symbol (libm, __llround, llroundl, GLIBC_2_1);
#endif
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