1 /* Supplemental information about the floating-point formats. 2 Copyright (C) 2007, 2009-2012 Free Software Foundation, Inc. 3 Written by Bruno Haible <bruno@clisp.org>, 2007. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3, or (at your option) 8 any later version. 9 10 This program 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 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; if not, see <http://www.gnu.org/licenses/>. */ 17 18 #ifndef _FLOATPLUS_H 19 #define _FLOATPLUS_H 20 21 #include <float.h> 22 #include <limits.h> 23 24 /* Number of bits in the mantissa of a floating-point number, including the 25 "hidden bit". */ 26 #if FLT_RADIX == 2 27 # define FLT_MANT_BIT FLT_MANT_DIG 28 # define DBL_MANT_BIT DBL_MANT_DIG 29 # define LDBL_MANT_BIT LDBL_MANT_DIG 30 #elif FLT_RADIX == 4 31 # define FLT_MANT_BIT (FLT_MANT_DIG * 2) 32 # define DBL_MANT_BIT (DBL_MANT_DIG * 2) 33 # define LDBL_MANT_BIT (LDBL_MANT_DIG * 2) 34 #elif FLT_RADIX == 16 35 # define FLT_MANT_BIT (FLT_MANT_DIG * 4) 36 # define DBL_MANT_BIT (DBL_MANT_DIG * 4) 37 # define LDBL_MANT_BIT (LDBL_MANT_DIG * 4) 38 #endif 39 40 /* Bit mask that can be used to mask the exponent, as an unsigned number. */ 41 #define FLT_EXP_MASK ((FLT_MAX_EXP - FLT_MIN_EXP) | 7) 42 #define DBL_EXP_MASK ((DBL_MAX_EXP - DBL_MIN_EXP) | 7) 43 #define LDBL_EXP_MASK ((LDBL_MAX_EXP - LDBL_MIN_EXP) | 7) 44 45 /* Number of bits used for the exponent of a floating-point number, including 46 the exponent's sign. */ 47 #define FLT_EXP_BIT \ 48 (FLT_EXP_MASK < 0x100 ? 8 : \ 49 FLT_EXP_MASK < 0x200 ? 9 : \ 50 FLT_EXP_MASK < 0x400 ? 10 : \ 51 FLT_EXP_MASK < 0x800 ? 11 : \ 52 FLT_EXP_MASK < 0x1000 ? 12 : \ 53 FLT_EXP_MASK < 0x2000 ? 13 : \ 54 FLT_EXP_MASK < 0x4000 ? 14 : \ 55 FLT_EXP_MASK < 0x8000 ? 15 : \ 56 FLT_EXP_MASK < 0x10000 ? 16 : \ 57 FLT_EXP_MASK < 0x20000 ? 17 : \ 58 FLT_EXP_MASK < 0x40000 ? 18 : \ 59 FLT_EXP_MASK < 0x80000 ? 19 : \ 60 FLT_EXP_MASK < 0x100000 ? 20 : \ 61 FLT_EXP_MASK < 0x200000 ? 21 : \ 62 FLT_EXP_MASK < 0x400000 ? 22 : \ 63 FLT_EXP_MASK < 0x800000 ? 23 : \ 64 FLT_EXP_MASK < 0x1000000 ? 24 : \ 65 FLT_EXP_MASK < 0x2000000 ? 25 : \ 66 FLT_EXP_MASK < 0x4000000 ? 26 : \ 67 FLT_EXP_MASK < 0x8000000 ? 27 : \ 68 FLT_EXP_MASK < 0x10000000 ? 28 : \ 69 FLT_EXP_MASK < 0x20000000 ? 29 : \ 70 FLT_EXP_MASK < 0x40000000 ? 30 : \ 71 FLT_EXP_MASK <= 0x7fffffff ? 31 : \ 72 32) 73 #define DBL_EXP_BIT \ 74 (DBL_EXP_MASK < 0x100 ? 8 : \ 75 DBL_EXP_MASK < 0x200 ? 9 : \ 76 DBL_EXP_MASK < 0x400 ? 10 : \ 77 DBL_EXP_MASK < 0x800 ? 11 : \ 78 DBL_EXP_MASK < 0x1000 ? 12 : \ 79 DBL_EXP_MASK < 0x2000 ? 13 : \ 80 DBL_EXP_MASK < 0x4000 ? 14 : \ 81 DBL_EXP_MASK < 0x8000 ? 15 : \ 82 DBL_EXP_MASK < 0x10000 ? 16 : \ 83 DBL_EXP_MASK < 0x20000 ? 17 : \ 84 DBL_EXP_MASK < 0x40000 ? 18 : \ 85 DBL_EXP_MASK < 0x80000 ? 19 : \ 86 DBL_EXP_MASK < 0x100000 ? 20 : \ 87 DBL_EXP_MASK < 0x200000 ? 21 : \ 88 DBL_EXP_MASK < 0x400000 ? 22 : \ 89 DBL_EXP_MASK < 0x800000 ? 23 : \ 90 DBL_EXP_MASK < 0x1000000 ? 24 : \ 91 DBL_EXP_MASK < 0x2000000 ? 25 : \ 92 DBL_EXP_MASK < 0x4000000 ? 26 : \ 93 DBL_EXP_MASK < 0x8000000 ? 27 : \ 94 DBL_EXP_MASK < 0x10000000 ? 28 : \ 95 DBL_EXP_MASK < 0x20000000 ? 29 : \ 96 DBL_EXP_MASK < 0x40000000 ? 30 : \ 97 DBL_EXP_MASK <= 0x7fffffff ? 31 : \ 98 32) 99 #define LDBL_EXP_BIT \ 100 (LDBL_EXP_MASK < 0x100 ? 8 : \ 101 LDBL_EXP_MASK < 0x200 ? 9 : \ 102 LDBL_EXP_MASK < 0x400 ? 10 : \ 103 LDBL_EXP_MASK < 0x800 ? 11 : \ 104 LDBL_EXP_MASK < 0x1000 ? 12 : \ 105 LDBL_EXP_MASK < 0x2000 ? 13 : \ 106 LDBL_EXP_MASK < 0x4000 ? 14 : \ 107 LDBL_EXP_MASK < 0x8000 ? 15 : \ 108 LDBL_EXP_MASK < 0x10000 ? 16 : \ 109 LDBL_EXP_MASK < 0x20000 ? 17 : \ 110 LDBL_EXP_MASK < 0x40000 ? 18 : \ 111 LDBL_EXP_MASK < 0x80000 ? 19 : \ 112 LDBL_EXP_MASK < 0x100000 ? 20 : \ 113 LDBL_EXP_MASK < 0x200000 ? 21 : \ 114 LDBL_EXP_MASK < 0x400000 ? 22 : \ 115 LDBL_EXP_MASK < 0x800000 ? 23 : \ 116 LDBL_EXP_MASK < 0x1000000 ? 24 : \ 117 LDBL_EXP_MASK < 0x2000000 ? 25 : \ 118 LDBL_EXP_MASK < 0x4000000 ? 26 : \ 119 LDBL_EXP_MASK < 0x8000000 ? 27 : \ 120 LDBL_EXP_MASK < 0x10000000 ? 28 : \ 121 LDBL_EXP_MASK < 0x20000000 ? 29 : \ 122 LDBL_EXP_MASK < 0x40000000 ? 30 : \ 123 LDBL_EXP_MASK <= 0x7fffffff ? 31 : \ 124 32) 125 126 /* Number of bits used for a floating-point number: the mantissa (not 127 counting the "hidden bit", since it may or may not be explicit), the 128 exponent, and the sign. */ 129 #define FLT_TOTAL_BIT ((FLT_MANT_BIT - 1) + FLT_EXP_BIT + 1) 130 #define DBL_TOTAL_BIT ((DBL_MANT_BIT - 1) + DBL_EXP_BIT + 1) 131 #define LDBL_TOTAL_BIT ((LDBL_MANT_BIT - 1) + LDBL_EXP_BIT + 1) 132 133 /* Number of bytes used for a floating-point number. 134 This can be smaller than the 'sizeof'. For example, on i386 systems, 135 'long double' most often have LDBL_MANT_BIT = 64, LDBL_EXP_BIT = 16, hence 136 LDBL_TOTAL_BIT = 80 bits, i.e. 10 bytes of consecutive memory, but 137 sizeof (long double) = 12 or = 16. */ 138 #define SIZEOF_FLT ((FLT_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT) 139 #define SIZEOF_DBL ((DBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT) 140 #define SIZEOF_LDBL ((LDBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT) 141 142 /* Verify that SIZEOF_FLT <= sizeof (float) etc. */ 143 typedef int verify_sizeof_flt[SIZEOF_FLT <= sizeof (float) ? 1 : -1]; 144 typedef int verify_sizeof_dbl[SIZEOF_DBL <= sizeof (double) ? 1 : - 1]; 145 typedef int verify_sizeof_ldbl[SIZEOF_LDBL <= sizeof (long double) ? 1 : - 1]; 146 147 #endif /* _FLOATPLUS_H */ 148