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1 /* Supplemental information about the floating-point formats.
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2 Copyright (C) 2007 Free Software Foundation, Inc.
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3 Written by Bruno Haible <bruno@clisp.org>, 2007.
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4
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5 This program is free software; you can redistribute it and/or modify
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6 it under the terms of the GNU General Public License as published by
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7 the Free Software Foundation; either version 3, or (at your option)
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8 any later version.
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9
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10 This program is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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13 GNU General Public License for more details.
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14
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15 You should have received a copy of the GNU General Public License
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16 along with this program; if not, write to the Free Software Foundation,
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17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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18
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19 #ifndef _FLOATPLUS_H
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20 #define _FLOATPLUS_H
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21
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22 #include <float.h>
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23 #include <limits.h>
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24
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25 /* Number of bits in the mantissa of a floating-point number, including the
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26 "hidden bit". */
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27 #if FLT_RADIX == 2
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28 # define FLT_MANT_BIT FLT_MANT_DIG
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29 # define DBL_MANT_BIT DBL_MANT_DIG
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30 # define LDBL_MANT_BIT LDBL_MANT_DIG
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31 #elif FLT_RADIX == 4
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32 # define FLT_MANT_BIT (FLT_MANT_DIG * 2)
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33 # define DBL_MANT_BIT (DBL_MANT_DIG * 2)
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34 # define LDBL_MANT_BIT (LDBL_MANT_DIG * 2)
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35 #elif FLT_RADIX == 16
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36 # define FLT_MANT_BIT (FLT_MANT_DIG * 4)
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37 # define DBL_MANT_BIT (DBL_MANT_DIG * 4)
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38 # define LDBL_MANT_BIT (LDBL_MANT_DIG * 4)
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39 #endif
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40
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41 /* Bit mask that can be used to mask the exponent, as an unsigned number. */
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42 #define FLT_EXP_MASK ((FLT_MAX_EXP - FLT_MIN_EXP) | 7)
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43 #define DBL_EXP_MASK ((DBL_MAX_EXP - DBL_MIN_EXP) | 7)
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44 #define LDBL_EXP_MASK ((LDBL_MAX_EXP - LDBL_MIN_EXP) | 7)
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45
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46 /* Number of bits used for the exponent of a floating-point number, including
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47 the exponent's sign. */
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48 #define FLT_EXP_BIT \
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49 (FLT_EXP_MASK < 0x100 ? 8 : \
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50 FLT_EXP_MASK < 0x200 ? 9 : \
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51 FLT_EXP_MASK < 0x400 ? 10 : \
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52 FLT_EXP_MASK < 0x800 ? 11 : \
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53 FLT_EXP_MASK < 0x1000 ? 12 : \
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54 FLT_EXP_MASK < 0x2000 ? 13 : \
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55 FLT_EXP_MASK < 0x4000 ? 14 : \
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56 FLT_EXP_MASK < 0x8000 ? 15 : \
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57 FLT_EXP_MASK < 0x10000 ? 16 : \
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58 FLT_EXP_MASK < 0x20000 ? 17 : \
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59 FLT_EXP_MASK < 0x40000 ? 18 : \
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60 FLT_EXP_MASK < 0x80000 ? 19 : \
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61 FLT_EXP_MASK < 0x100000 ? 20 : \
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62 FLT_EXP_MASK < 0x200000 ? 21 : \
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63 FLT_EXP_MASK < 0x400000 ? 22 : \
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64 FLT_EXP_MASK < 0x800000 ? 23 : \
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65 FLT_EXP_MASK < 0x1000000 ? 24 : \
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66 FLT_EXP_MASK < 0x2000000 ? 25 : \
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67 FLT_EXP_MASK < 0x4000000 ? 26 : \
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68 FLT_EXP_MASK < 0x8000000 ? 27 : \
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69 FLT_EXP_MASK < 0x10000000 ? 28 : \
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70 FLT_EXP_MASK < 0x20000000 ? 29 : \
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71 FLT_EXP_MASK < 0x40000000 ? 30 : \
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72 FLT_EXP_MASK <= 0x7fffffff ? 31 : \
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73 32)
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74 #define DBL_EXP_BIT \
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75 (DBL_EXP_MASK < 0x100 ? 8 : \
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76 DBL_EXP_MASK < 0x200 ? 9 : \
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77 DBL_EXP_MASK < 0x400 ? 10 : \
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78 DBL_EXP_MASK < 0x800 ? 11 : \
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79 DBL_EXP_MASK < 0x1000 ? 12 : \
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80 DBL_EXP_MASK < 0x2000 ? 13 : \
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81 DBL_EXP_MASK < 0x4000 ? 14 : \
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82 DBL_EXP_MASK < 0x8000 ? 15 : \
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83 DBL_EXP_MASK < 0x10000 ? 16 : \
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84 DBL_EXP_MASK < 0x20000 ? 17 : \
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85 DBL_EXP_MASK < 0x40000 ? 18 : \
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86 DBL_EXP_MASK < 0x80000 ? 19 : \
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87 DBL_EXP_MASK < 0x100000 ? 20 : \
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88 DBL_EXP_MASK < 0x200000 ? 21 : \
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89 DBL_EXP_MASK < 0x400000 ? 22 : \
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90 DBL_EXP_MASK < 0x800000 ? 23 : \
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91 DBL_EXP_MASK < 0x1000000 ? 24 : \
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92 DBL_EXP_MASK < 0x2000000 ? 25 : \
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93 DBL_EXP_MASK < 0x4000000 ? 26 : \
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94 DBL_EXP_MASK < 0x8000000 ? 27 : \
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95 DBL_EXP_MASK < 0x10000000 ? 28 : \
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96 DBL_EXP_MASK < 0x20000000 ? 29 : \
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97 DBL_EXP_MASK < 0x40000000 ? 30 : \
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98 DBL_EXP_MASK <= 0x7fffffff ? 31 : \
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99 32)
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100 #define LDBL_EXP_BIT \
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101 (LDBL_EXP_MASK < 0x100 ? 8 : \
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102 LDBL_EXP_MASK < 0x200 ? 9 : \
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103 LDBL_EXP_MASK < 0x400 ? 10 : \
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104 LDBL_EXP_MASK < 0x800 ? 11 : \
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105 LDBL_EXP_MASK < 0x1000 ? 12 : \
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106 LDBL_EXP_MASK < 0x2000 ? 13 : \
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107 LDBL_EXP_MASK < 0x4000 ? 14 : \
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108 LDBL_EXP_MASK < 0x8000 ? 15 : \
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109 LDBL_EXP_MASK < 0x10000 ? 16 : \
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110 LDBL_EXP_MASK < 0x20000 ? 17 : \
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111 LDBL_EXP_MASK < 0x40000 ? 18 : \
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112 LDBL_EXP_MASK < 0x80000 ? 19 : \
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113 LDBL_EXP_MASK < 0x100000 ? 20 : \
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114 LDBL_EXP_MASK < 0x200000 ? 21 : \
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115 LDBL_EXP_MASK < 0x400000 ? 22 : \
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116 LDBL_EXP_MASK < 0x800000 ? 23 : \
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117 LDBL_EXP_MASK < 0x1000000 ? 24 : \
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118 LDBL_EXP_MASK < 0x2000000 ? 25 : \
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119 LDBL_EXP_MASK < 0x4000000 ? 26 : \
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120 LDBL_EXP_MASK < 0x8000000 ? 27 : \
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121 LDBL_EXP_MASK < 0x10000000 ? 28 : \
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122 LDBL_EXP_MASK < 0x20000000 ? 29 : \
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123 LDBL_EXP_MASK < 0x40000000 ? 30 : \
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124 LDBL_EXP_MASK <= 0x7fffffff ? 31 : \
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125 32)
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126
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127 /* Number of bits used for a floating-point number: the mantissa (not
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128 counting the "hidden bit", since it may or may not be explicit), the
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129 exponent, and the sign. */
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130 #define FLT_TOTAL_BIT ((FLT_MANT_BIT - 1) + FLT_EXP_BIT + 1)
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131 #define DBL_TOTAL_BIT ((DBL_MANT_BIT - 1) + DBL_EXP_BIT + 1)
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132 #define LDBL_TOTAL_BIT ((LDBL_MANT_BIT - 1) + LDBL_EXP_BIT + 1)
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133
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134 /* Number of bytes used for a floating-point number.
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135 This can be smaller than the 'sizeof'. For example, on i386 systems,
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136 'long double' most often have LDBL_MANT_BIT = 64, LDBL_EXP_BIT = 16, hence
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137 LDBL_TOTAL_BIT = 80 bits, i.e. 10 bytes of consecutive memory, but
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138 sizeof (long double) = 12 or = 16. */
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139 #define SIZEOF_FLT ((FLT_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
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140 #define SIZEOF_DBL ((DBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
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141 #define SIZEOF_LDBL ((LDBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
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142
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143 /* Verify that SIZEOF_FLT <= sizeof (float) etc. */
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144 typedef int verify_sizeof_flt[2 * (SIZEOF_FLT <= sizeof (float)) - 1];
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145 typedef int verify_sizeof_dbl[2 * (SIZEOF_DBL <= sizeof (double)) - 1];
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146 typedef int verify_sizeof_ldbl[2 * (SIZEOF_LDBL <= sizeof (long double)) - 1];
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147
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148 #endif /* _FLOATPLUS_H */
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