lib/float.in.h

   1 /* A correct <float.h>.
   2
   3    Copyright (C) 2007-2019 Free Software Foundation, Inc.
   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 of the License, or
   8    (at your option) 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 <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _@GUARD_PREFIX@_FLOAT_H
  19
  20 #if __GNUC__ >= 3
  21 @PRAGMA_SYSTEM_HEADER@
  22 #endif
  23 @PRAGMA_COLUMNS@
  24
  25 /* The include_next requires a split double-inclusion guard.  */
  26 #@INCLUDE_NEXT@ @NEXT_FLOAT_H@
  27
  28 #ifndef _@GUARD_PREFIX@_FLOAT_H
  29 #define _@GUARD_PREFIX@_FLOAT_H
  30
  31 /* 'long double' properties.  */
  32
  33 #if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
  34 /* Number of mantissa units, in base FLT_RADIX.  */
  35 # undef LDBL_MANT_DIG
  36 # define LDBL_MANT_DIG   64
  37 /* Number of decimal digits that is sufficient for representing a number.  */
  38 # undef LDBL_DIG
  39 # define LDBL_DIG        18
  40 /* x-1 where x is the smallest representable number > 1.  */
  41 # undef LDBL_EPSILON
  42 # define LDBL_EPSILON    1.0842021724855044340E-19L
  43 /* Minimum e such that FLT_RADIX^(e-1) is a normalized number.  */
  44 # undef LDBL_MIN_EXP
  45 # define LDBL_MIN_EXP    (-16381)
  46 /* Maximum e such that FLT_RADIX^(e-1) is a representable finite number.  */
  47 # undef LDBL_MAX_EXP
  48 # define LDBL_MAX_EXP    16384
  49 /* Minimum positive normalized number.  */
  50 # undef LDBL_MIN
  51 # define LDBL_MIN        3.3621031431120935063E-4932L
  52 /* Maximum representable finite number.  */
  53 # undef LDBL_MAX
  54 # define LDBL_MAX        1.1897314953572317650E+4932L
  55 /* Minimum e such that 10^e is in the range of normalized numbers.  */
  56 # undef LDBL_MIN_10_EXP
  57 # define LDBL_MIN_10_EXP (-4931)
  58 /* Maximum e such that 10^e is in the range of representable finite numbers.  */
  59 # undef LDBL_MAX_10_EXP
  60 # define LDBL_MAX_10_EXP 4932
  61 #endif
  62
  63 /* On FreeBSD/x86 6.4, the 'long double' type really has only 53 bits of
  64    precision in the compiler but 64 bits of precision at runtime.  See
  65    <https://lists.gnu.org/r/bug-gnulib/2008-07/msg00063.html>.  */
  66 #if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__)
  67 /* Number of mantissa units, in base FLT_RADIX.  */
  68 # undef LDBL_MANT_DIG
  69 # define LDBL_MANT_DIG   64
  70 /* Number of decimal digits that is sufficient for representing a number.  */
  71 # undef LDBL_DIG
  72 # define LDBL_DIG        18
  73 /* x-1 where x is the smallest representable number > 1.  */
  74 # undef LDBL_EPSILON
  75 # define LDBL_EPSILON 1.084202172485504434007452800869941711426e-19L /* 2^-63 */
  76 /* Minimum e such that FLT_RADIX^(e-1) is a normalized number.  */
  77 # undef LDBL_MIN_EXP
  78 # define LDBL_MIN_EXP    (-16381)
  79 /* Maximum e such that FLT_RADIX^(e-1) is a representable finite number.  */
  80 # undef LDBL_MAX_EXP
  81 # define LDBL_MAX_EXP    16384
  82 /* Minimum positive normalized number.  */
  83 # undef LDBL_MIN
  84 # define LDBL_MIN        3.362103143112093506262677817321752E-4932L /* = 0x1p-16382L */
  85 /* Maximum representable finite number.  */
  86 # undef LDBL_MAX
  87 /* LDBL_MAX is represented as { 0xFFFFFFFF, 0xFFFFFFFF, 32766 }.
  88    But the largest literal that GCC allows us to write is
  89    0x0.fffffffffffff8p16384L = { 0xFFFFF800, 0xFFFFFFFF, 32766 }.
  90    So, define it like this through a reference to an external variable
  91
  92      const unsigned int LDBL_MAX[3] = { 0xFFFFFFFF, 0xFFFFFFFF, 32766 };
  93      extern const long double LDBL_MAX;
  94
  95    Unfortunately, this is not a constant expression.  */
  96 union gl_long_double_union
  97   {
  98     struct { unsigned int lo; unsigned int hi; unsigned int exponent; } xd;
  99     long double ld;
 100   };
 101 extern const union gl_long_double_union gl_LDBL_MAX;
 102 # define LDBL_MAX (gl_LDBL_MAX.ld)
 103 /* Minimum e such that 10^e is in the range of normalized numbers.  */
 104 # undef LDBL_MIN_10_EXP
 105 # define LDBL_MIN_10_EXP (-4931)
 106 /* Maximum e such that 10^e is in the range of representable finite numbers.  */
 107 # undef LDBL_MAX_10_EXP
 108 # define LDBL_MAX_10_EXP 4932
 109 #endif
 110
 111 /* On AIX 7.1 with gcc 4.2, the values of LDBL_MIN_EXP, LDBL_MIN, LDBL_MAX are
 112    wrong.
 113    On Linux/PowerPC with gcc 4.4, the value of LDBL_MAX is wrong.  */
 114 #if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__
 115 # undef LDBL_MIN_EXP
 116 # define LDBL_MIN_EXP DBL_MIN_EXP
 117 # undef LDBL_MIN_10_EXP
 118 # define LDBL_MIN_10_EXP DBL_MIN_10_EXP
 119 # undef LDBL_MIN
 120 # define LDBL_MIN 2.22507385850720138309023271733240406422e-308L /* DBL_MIN = 2^-1022 */
 121 #endif
 122 #if (defined _ARCH_PPC || defined _POWER) && (defined _AIX || defined __linux__) && (LDBL_MANT_DIG == 106) && defined __GNUC__
 123 # undef LDBL_MAX
 124 /* LDBL_MAX is represented as { 0x7FEFFFFF, 0xFFFFFFFF, 0x7C8FFFFF, 0xFFFFFFFF }.
 125    It is not easy to define:
 126      #define LDBL_MAX 1.79769313486231580793728971405302307166e308L
 127    is too small, whereas
 128      #define LDBL_MAX 1.79769313486231580793728971405302307167e308L
 129    is too large.  Apparently a bug in GCC decimal-to-binary conversion.
 130    Also, I can't get values larger than
 131      #define LDBL63 ((long double) (1ULL << 63))
 132      #define LDBL882 (LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63)
 133      #define LDBL945 (LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63)
 134      #define LDBL1008 (LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63 * LDBL63)
 135      #define LDBL_MAX (LDBL1008 * 65535.0L + LDBL945 * (long double) 9223372036821221375ULL + LDBL882 * (long double) 4611686018427387904ULL)
 136    which is represented as { 0x7FEFFFFF, 0xFFFFFFFF, 0x7C8FFFFF, 0xF8000000 }.
 137    So, define it like this through a reference to an external variable
 138
 139      const double LDBL_MAX[2] = { DBL_MAX, DBL_MAX / (double)134217728UL / (double)134217728UL };
 140      extern const long double LDBL_MAX;
 141
 142    or through a pointer cast
 143
 144      #define LDBL_MAX \
 145        (*(const long double *) (double[]) { DBL_MAX, DBL_MAX / (double)134217728UL / (double)134217728UL })
 146
 147    Unfortunately, this is not a constant expression, and the latter expression
 148    does not work well when GCC is optimizing..  */
 149 union gl_long_double_union
 150   {
 151     struct { double hi; double lo; } dd;
 152     long double ld;
 153   };
 154 extern const union gl_long_double_union gl_LDBL_MAX;
 155 # define LDBL_MAX (gl_LDBL_MAX.ld)
 156 #endif
 157
 158 /* On IRIX 6.5, with cc, the value of LDBL_MANT_DIG is wrong.
 159    On IRIX 6.5, with gcc 4.2, the values of LDBL_MIN_EXP, LDBL_MIN, LDBL_EPSILON
 160    are wrong.  */
 161 #if defined __sgi && (LDBL_MANT_DIG >= 106)
 162 # undef LDBL_MANT_DIG
 163 # define LDBL_MANT_DIG 106
 164 # if defined __GNUC__
 165 #  undef LDBL_MIN_EXP
 166 #  define LDBL_MIN_EXP DBL_MIN_EXP
 167 #  undef LDBL_MIN_10_EXP
 168 #  define LDBL_MIN_10_EXP DBL_MIN_10_EXP
 169 #  undef LDBL_MIN
 170 #  define LDBL_MIN 2.22507385850720138309023271733240406422e-308L /* DBL_MIN = 2^-1022 */
 171 #  undef LDBL_EPSILON
 172 #  define LDBL_EPSILON 2.46519032881566189191165176650870696773e-32L /* 2^-105 */
 173 # endif
 174 #endif
 175
 176 #if @REPLACE_ITOLD@
 177 /* Pull in a function that fixes the 'int' to 'long double' conversion
 178    of glibc 2.7.  */
 179 extern
 180 # ifdef __cplusplus
 181 "C"
 182 # endif
 183 void _Qp_itoq (long double *, int);
 184 static void (*_gl_float_fix_itold) (long double *, int) = _Qp_itoq;
 185 #endif
 186
 187 #endif /* _@GUARD_PREFIX@_FLOAT_H */
 188 #endif /* _@GUARD_PREFIX@_FLOAT_H */