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/* Double-precision math error handling.
Copyright (C) 2018-2020 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 <math-barriers.h>
#include "math_config.h"
#if WANT_ERRNO
#include <errno.h>
/* NOINLINE reduces code size and avoids making math functions non-leaf
when the error handling is inlined. */
NOINLINE static double
with_errno (double y, int e)
{
errno = e;
return y;
}
#else
#define with_errno(x, e) (x)
#endif
/* NOINLINE reduces code size. */
NOINLINE static double
xflow (uint32_t sign, double y)
{
y = math_opt_barrier (sign ? -y : y) * y;
return with_errno (y, ERANGE);
}
attribute_hidden double
__math_uflow (uint32_t sign)
{
return xflow (sign, 0x1p-767);
}
#if WANT_ERRNO_UFLOW
/* Underflows to zero in some non-nearest rounding mode, setting errno
is valid even if the result is non-zero, but in the subnormal range. */
attribute_hidden double
__math_may_uflow (uint32_t sign)
{
return xflow (sign, 0x1.8p-538);
}
#endif
attribute_hidden double
__math_oflow (uint32_t sign)
{
return xflow (sign, 0x1p769);
}
attribute_hidden double
__math_divzero (uint32_t sign)
{
double y = math_opt_barrier (sign ? -1.0 : 1.0) / 0.0;
return with_errno (y, ERANGE);
}
attribute_hidden double
__math_invalid (double x)
{
double y = (x - x) / (x - x);
return isnan (x) ? y : with_errno (y, EDOM);
}
/* Check result and set errno if necessary. */
attribute_hidden double
__math_check_uflow (double y)
{
return y == 0.0 ? with_errno (y, ERANGE) : y;
}
attribute_hidden double
__math_check_oflow (double y)
{
return isinf (y) ? with_errno (y, ERANGE) : y;
}
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