Retro68/gcc/libquadmath/math/roundq.c
Wolfgang Thaller 6fbf4226da gcc-9.1
2019-06-20 20:10:10 +02:00

79 lines
1.8 KiB
C

/* Round long double to integer away from zero.
Copyright (C) 1997-2018 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, see
<http://www.gnu.org/licenses/>. */
#define NO_MATH_REDIRECT
#include "quadmath-imp.h"
__float128
roundq (__float128 x)
{
int32_t j0;
uint64_t i1, i0;
GET_FLT128_WORDS64 (i0, i1, x);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
if (j0 < 48)
{
if (j0 < 0)
{
i0 &= 0x8000000000000000ULL;
if (j0 == -1)
i0 |= 0x3fff000000000000LL;
i1 = 0;
}
else
{
uint64_t i = 0x0000ffffffffffffLL >> j0;
if (((i0 & i) | i1) == 0)
/* X is integral. */
return x;
i0 += 0x0000800000000000LL >> j0;
i0 &= ~i;
i1 = 0;
}
}
else if (j0 > 111)
{
if (j0 == 0x4000)
/* Inf or NaN. */
return x + x;
else
return x;
}
else
{
uint64_t i = -1ULL >> (j0 - 48);
if ((i1 & i) == 0)
/* X is integral. */
return x;
uint64_t j = i1 + (1LL << (111 - j0));
if (j < i1)
i0 += 1;
i1 = j;
i1 &= ~i;
}
SET_FLT128_WORDS64 (x, i0, i1);
return x;
}