gcc/libquadmath/math/llroundq.c

74 lines
2.0 KiB
C

/* Round long double value to long long int.
Copyright (C) 1997, 1999, 2004 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include "quadmath-imp.h"
long long int
llroundq (__float128 x)
{
int64_t j0;
uint64_t i1, i0;
long long int result;
int sign;
GET_FLT128_WORDS64 (i0, i1, x);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1;
i0 &= 0x0000ffffffffffffLL;
i0 |= 0x0001000000000000LL;
if (j0 < 48)
{
if (j0 < 0)
return j0 < -1 ? 0 : sign;
else
{
i0 += 0x0000800000000000LL >> j0;
result = i0 >> (48 - j0);
}
}
else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
{
if (j0 >= 112)
result = ((long long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
else
{
uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48));
if (j < i1)
++i0;
if (j0 == 48)
result = (long long int) i0;
else
result = ((long long int) i0 << (j0 - 48)) | (j >> (112 - j0));
}
}
else
{
/* The number is too large. It is left implementation defined
what happens. */
return (long long int) x;
}
return sign * result;
}