glibc/math/s_exp10m1_template.c

46 lines
1.5 KiB
C

/* Return exp10(X) - 1.
Copyright (C) 2024-2025 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 <errno.h>
#include <math.h>
#include <math_private.h>
#include <math-underflow.h>
FLOAT
M_DECL_FUNC (__exp10m1) (FLOAT x)
{
if (isgreaterequal (x, M_LIT (-0.5)) && islessequal (x, M_LIT (0.5)))
{
FLOAT ret = M_SUF (__expm1) (M_MLIT (M_LN10) * x);
math_check_force_underflow (ret);
return ret;
}
else if (isgreater (x, M_MANT_DIG / 3 + M_LIT (2.0)))
{
FLOAT ret = M_SUF (__ieee754_exp10) (x);
if (!isfinite (ret) && isfinite (x))
__set_errno (ERANGE);
return ret;
}
else if (isless (x, -(M_MANT_DIG / 3) - M_LIT (2.0)))
return M_LIT (-1.0);
else
return M_SUF (__ieee754_exp10) (x) - M_LIT (1.0);
}
declare_mgen_alias (__exp10m1, exp10m1);