1 /* Copyright (C) 2012-2021 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 23 static const double log10_high = 0x2.4d7637p0; 24 static const double log10_low = 0x7.6aaa2b05ba95cp-28; 25 26 double __ieee754_exp10(double arg)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 } 51 libm_alias_finite (__ieee754_exp10, __exp10) 52