glibc/sysdeps/ieee754/dbl-64/e_exp10.c

49 lines
1.5 KiB
C

/* Copyright (C) 2012-2014 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
<http://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <float.h>
static const double log10_high = 0x2.4d7637p0;
static const double log10_low = 0x7.6aaa2b05ba95cp-28;
double
__ieee754_exp10 (double arg)
{
int32_t lx;
double arg_high, arg_low;
double exp_high, exp_low;
if (!__finite (arg))
return __ieee754_exp (arg);
if (arg < DBL_MIN_10_EXP - DBL_DIG - 10)
return DBL_MIN * DBL_MIN;
else if (arg > DBL_MAX_10_EXP + 1)
return DBL_MAX * DBL_MAX;
GET_LOW_WORD (lx, arg);
lx &= 0xf8000000;
arg_high = arg;
SET_LOW_WORD (arg_high, lx);
arg_low = arg - arg_high;
exp_high = arg_high * log10_high;
exp_low = arg_high * log10_low + arg_low * M_LN10;
return __ieee754_exp (exp_high) * __ieee754_exp (exp_low);
}
strong_alias (__ieee754_exp10, __exp10_finite)