glibc/sysdeps/ieee754/ldbl-128/s_llroundl.c

102 lines
2.7 KiB
C

/* Round long double value to long long int.
Copyright (C) 1997-2024 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
<https://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <limits.h>
#include <math.h>
#include <math_private.h>
#include <libm-alias-ldouble.h>
#include <fix-fp-int-convert-overflow.h>
long long int
__llroundl (_Float128 x)
{
int64_t j0;
uint64_t i1, i0;
long long int result;
int sign;
GET_LDOUBLE_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));
#ifdef FE_INVALID
if (sign == 1 && result == LLONG_MIN)
/* Rounding brought the value out of range. */
feraiseexcept (FE_INVALID);
#endif
}
}
}
else
{
/* The number is too large. Unless it rounds to LLONG_MIN,
FE_INVALID must be raised and the return value is
unspecified. */
#ifdef FE_INVALID
if (FIX_LDBL_LLONG_CONVERT_OVERFLOW
&& !(sign == -1 && x > (_Float128) LLONG_MIN - L(0.5)))
{
feraiseexcept (FE_INVALID);
return sign == 1 ? LLONG_MAX : LLONG_MIN;
}
else if (!FIX_LDBL_LLONG_CONVERT_OVERFLOW
&& x <= (_Float128) LLONG_MIN - L(0.5))
{
/* If truncation produces LLONG_MIN, the cast will not raise
the exception, but may raise "inexact". */
feraiseexcept (FE_INVALID);
return LLONG_MIN;
}
#endif
return (long long int) x;
}
return sign * result;
}
libm_alias_ldouble (__llround, llround)