1/* Copyright (C) 2012-2020 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <math.h>
19#include <math_private.h>
20#include <float.h>
21#include <libm-alias-finite.h>
22
23static const double log10_high = 0x2.4d7637p0;
24static const double log10_low = 0x7.6aaa2b05ba95cp-28;
25
26double
27__ieee754_exp10 (double arg)
28{
29 int32_t lx;
30 double arg_high, arg_low;
31 double exp_high, exp_low;
32
33 if (!isfinite (arg))
34 return __ieee754_exp (arg);
35 if (arg < DBL_MIN_10_EXP - DBL_DIG - 10)
36 return DBL_MIN * DBL_MIN;
37 else if (arg > DBL_MAX_10_EXP + 1)
38 return DBL_MAX * DBL_MAX;
39 else if (fabs (arg) < 0x1p-56)
40 return 1.0;
41
42 GET_LOW_WORD (lx, arg);
43 lx &= 0xf8000000;
44 arg_high = arg;
45 SET_LOW_WORD (arg_high, lx);
46 arg_low = arg - arg_high;
47 exp_high = arg_high * log10_high;
48 exp_low = arg_high * log10_low + arg_low * M_LN10;
49 return __ieee754_exp (exp_high) * __ieee754_exp (exp_low);
50}
51libm_alias_finite (__ieee754_exp10, __exp10)
52