1 /* Macros for the implementation of *cvt functions, double version. 2 Copyright (C) 1995-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #include <float.h> 20 21 #define FLOAT_TYPE double 22 #define FUNC_PREFIX 23 #define FLOAT_FMT_FLAG 24 #define FLOAT_NAME_EXT 25 #define FLOAT_MIN_10_EXP DBL_MIN_10_EXP 26 /* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we 27 don't have log10 available in the preprocessor. */ 28 #define MAXDIG (NDIGIT_MAX + 3) 29 #define FCVT_MAXDIG (DBL_MAX_10_EXP + MAXDIG) 30 #if DBL_MANT_DIG == 53 31 # define NDIGIT_MAX 17 32 #elif DBL_MANT_DIG == 24 33 # define NDIGIT_MAX 9 34 #elif DBL_MANT_DIG == 56 35 # define NDIGIT_MAX 18 36 #else 37 /* See IEEE 854 5.6, table 2 for this formula. Unfortunately we need a 38 compile time constant here, so we cannot use it. */ 39 # error "NDIGIT_MAX must be precomputed" 40 # define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0))) 41 #endif 42 #if DBL_MIN_10_EXP == -37 43 # define FLOAT_MIN_10_NORM 1.0e-37 44 #elif DBL_MIN_10_EXP == -307 45 # define FLOAT_MIN_10_NORM 1.0e-307 46 #elif DBL_MIN_10_EXP == -4931 47 # define FLOAT_MIN_10_NORM 1.0e-4931 48 #else 49 /* libc can't depend on libm. */ 50 # error "FLOAT_MIN_10_NORM must be precomputed" 51 # define FLOAT_MIN_10_NORM exp10 (DBL_MIN_10_EXP) 52 #endif 53