1 /* Header file for constants used in floating point <-> decimal conversions. 2 Copyright (C) 1995-2022 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 #ifndef _FPIOCONST_H 20 #define _FPIOCONST_H 21 22 #include <float.h> 23 #include <math.h> 24 #include <gmp.h> 25 26 27 /* These values are used by __printf_fp, where they are noncritical (if the 28 value is not large enough, it will just be slower); and by 29 strtof/strtod/strtold, where it is critical (it's used for overflow 30 detection). 31 32 XXX These should be defined in <float.h>. For the time being, we have the 33 IEEE754 values here. */ 34 35 #if !defined __NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ > 1024 36 # define LDBL_MAX_10_EXP_LOG 12 /* = floor(log_2(LDBL_MAX_10_EXP)) */ 37 #else 38 # define LDBL_MAX_10_EXP_LOG 8 /* = floor(log_2(LDBL_MAX_10_EXP)) */ 39 #endif 40 #define DBL_MAX_10_EXP_LOG 8 /* = floor(log_2(DBL_MAX_10_EXP)) */ 41 #define FLT_MAX_10_EXP_LOG 5 /* = floor(log_2(FLT_MAX_10_EXP)) */ 42 43 /* On some machines, _Float128 may be ABI-distinct from long double (e.g 44 IBM extended precision). */ 45 #include <bits/floatn.h> 46 47 #if __HAVE_DISTINCT_FLOAT128 48 # define FLT128_MAX_10_EXP_LOG 12 /* = floor(log_2(FLT128_MAX_10_EXP)) */ 49 #endif 50 51 /* For strtold, we need powers of 10 up to floor (log_2 (LDBL_MANT_DIG 52 - LDBL_MIN_EXP + 2)). When _Float128 is enabled in libm and it is 53 ABI-distinct from long double (e.g. on powerpc64le), we also need powers 54 of 10 up to floor (log_2 (FLT128_MANT_DIG - FLT128_MIN_EXP + 2)). */ 55 #define FPIOCONST_HAVE_EXTENDED_RANGE \ 56 ((!defined __NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ > 1024) \ 57 || __HAVE_DISTINCT_FLOAT128) 58 59 #if FPIOCONST_HAVE_EXTENDED_RANGE 60 # define FPIOCONST_POW10_ARRAY_SIZE 15 61 #else 62 # define FPIOCONST_POW10_ARRAY_SIZE 11 63 #endif 64 65 /* The array with the number representation. */ 66 extern const mp_limb_t __tens[] attribute_hidden; 67 68 /* Table of powers of ten. This is used by __printf_fp and by 69 strtof/strtod/strtold. */ 70 struct mp_power 71 { 72 size_t arrayoff; /* Offset in `__tens'. */ 73 mp_size_t arraysize; /* Size of the array. */ 74 int p_expo; /* Exponent of the number 10^(2^i). */ 75 int m_expo; /* Exponent of the number 10^-(2^i-1). */ 76 }; 77 extern const struct mp_power _fpioconst_pow10[FPIOCONST_POW10_ARRAY_SIZE] 78 attribute_hidden; 79 80 /* The constants in the array `_fpioconst_pow10' have an offset. */ 81 #if BITS_PER_MP_LIMB == 32 82 # define _FPIO_CONST_OFFSET 2 83 #else 84 # define _FPIO_CONST_OFFSET 1 85 #endif 86 87 88 #endif /* fpioconst.h */ 89