glibc/sysdeps/ieee754/ldbl-128ibm/e_exp10l.c

50 lines
1.6 KiB
C

/* Copyright (C) 2012-2024 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 <math.h>
#include <math_private.h>
#include <float.h>
#include <libm-alias-finite.h>
static const long double log10_high = 0x2.4d763776aaap+0L;
static const long double log10_low = 0x2.b05ba95b58ae0b4c28a38a3fb4p-48L;
long double
__ieee754_exp10l (long double arg)
{
union ibm_extended_long_double u;
long double arg_high, arg_low;
long double exp_high, exp_low;
if (!isfinite (arg))
return __ieee754_expl (arg);
if (arg < LDBL_MIN_10_EXP - LDBL_DIG - 10)
return LDBL_MIN * LDBL_MIN;
else if (arg > LDBL_MAX_10_EXP + 1)
return LDBL_MAX * LDBL_MAX;
else if (fabsl (arg) < 0x1p-109L)
return 1.0L;
u.ld = arg;
arg_high = u.d[0].d;
arg_low = u.d[1].d;
exp_high = arg_high * log10_high;
exp_low = arg_high * log10_low + arg_low * M_LN10l;
return __ieee754_expl (exp_high) * __ieee754_expl (exp_low);
}
libm_alias_finite (__ieee754_exp10l, __exp10l)