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/* Round double value to long int.
Copyright (C) 1997-2025 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-double.h>
#include <fix-fp-int-convert-overflow.h>
/* For LP64, lround is an alias for llround. */
#ifndef _LP64
long int
__lround (double x)
{
int32_t j0;
int64_t i0;
long int result;
int sign;
EXTRACT_WORDS64 (i0, x);
j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
sign = i0 < 0 ? -1 : 1;
i0 &= UINT64_C(0xfffffffffffff);
i0 |= UINT64_C(0x10000000000000);
if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
{
if (j0 < 0)
return j0 < -1 ? 0 : sign;
else if (j0 >= 52)
result = i0 << (j0 - 52);
else
{
i0 += UINT64_C(0x8000000000000) >> j0;
result = i0 >> (52 - j0);
#ifdef FE_INVALID
if (sizeof (long int) == 4
&& sign == 1
&& result == LONG_MIN)
/* Rounding brought the value out of range. */
feraiseexcept (FE_INVALID);
#endif
}
}
else
{
/* The number is too large. Unless it rounds to LONG_MIN,
FE_INVALID must be raised and the return value is
unspecified. */
#ifdef FE_INVALID
if (FIX_DBL_LONG_CONVERT_OVERFLOW
&& !(sign == -1
&& (sizeof (long int) == 4
? x > (double) LONG_MIN - 0.5
: x >= (double) LONG_MIN)))
{
feraiseexcept (FE_INVALID);
return sign == 1 ? LONG_MAX : LONG_MIN;
}
else if (!FIX_DBL_LONG_CONVERT_OVERFLOW
&& sizeof (long int) == 4
&& x <= (double) LONG_MIN - 0.5)
{
/* If truncation produces LONG_MIN, the cast will not raise
the exception, but may raise "inexact". */
feraiseexcept (FE_INVALID);
return LONG_MIN;
}
#endif
return (long int) x;
}
return sign * result;
}
libm_alias_double (__lround, lround)
#endif
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