sysdeps/ieee754/float128/ieee754_float128.h

   1 /* _Float128 IEEE like macros.
   2    Copyright (C) 2017-2018 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    <http://www.gnu.org/licenses/>.  */
  18 #ifndef _IEEE754_FLOAT128_H
  19 #define _IEEE754_FLOAT128_H
  20
  21 #include <endian.h>
  22 #include <stdint.h>
  23
  24 # if __FLOAT_WORD_ORDER == BIG_ENDIAN
  25 #  define __FLT_EORDER2(t, a, b) t a; t b;
  26 #  define __FLT_EORDER4(t, a, b, c, d) \
  27                         t a; t b; t c; t d;
  28 #  define __FLT_EORDER6(t, a, b, c, d, e, f)  \
  29                         t a; t b; t c; t d; t e; t f;
  30 #  define __FLT_EORDER7(t, a, b, c, d, e, f, g)  \
  31                         t a; t b; t c; t d; t e; t f; t g;
  32 # else
  33 #  define __FLT_EORDER2(t, a, b) \
  34                         t b; t a;
  35 #  define __FLT_EORDER4(t, a, b, c, d) \
  36                         t d; t c; t b; t a;
  37 #  define __FLT_EORDER6(t, a, b, c, d, e, f)  \
  38                         t f; t e; t d; t c; t b; t a;
  39 #  define __FLT_EORDER7(t, a, b, c, d, e, f, g)  \
  40                         t g; t f; t e; t d; t c; t b; t a;
  41 # endif
  42
  43 /* A union which permits us to convert between _Float128 and
  44    four 32 bit ints or two 64 bit ints.  */
  45
  46 typedef union
  47 {
  48   _Float128 value;
  49   struct
  50   {
  51     __FLT_EORDER2 (uint64_t, msw, lsw);
  52   } parts64;
  53   struct
  54   {
  55     __FLT_EORDER4 (uint32_t, w0, w1, w2, w3);
  56   } parts32;
  57 } ieee854_float128_shape_type;
  58
  59 /* Get two 64 bit ints from a _Float128.  */
  60
  61 # define GET_FLOAT128_WORDS64(ix0,ix1,d)                        \
  62 do {                                                            \
  63   ieee854_float128_shape_type qw_u;                             \
  64   qw_u.value = (d);                                             \
  65   (ix0) = qw_u.parts64.msw;                                     \
  66   (ix1) = qw_u.parts64.lsw;                                     \
  67 } while (0)
  68
  69 /* Set a _Float128 from two 64 bit ints.  */
  70
  71 # define SET_FLOAT128_WORDS64(d,ix0,ix1)                        \
  72 do {                                                            \
  73   ieee854_float128_shape_type qw_u;                             \
  74   qw_u.parts64.msw = (ix0);                                     \
  75   qw_u.parts64.lsw = (ix1);                                     \
  76   (d) = qw_u.value;                                             \
  77 } while (0)
  78
  79 /* Get the more significant 64 bits of a _Float128 mantissa.  */
  80
  81 # define GET_FLOAT128_MSW64(v,d)                                \
  82 do {                                                            \
  83   ieee854_float128_shape_type sh_u;                             \
  84   sh_u.value = (d);                                             \
  85   (v) = sh_u.parts64.msw;                                       \
  86 } while (0)
  87
  88 /* Set the more significant 64 bits of a _Float128 mantissa from an int.  */
  89
  90 # define SET_FLOAT128_MSW64(d,v)                                \
  91 do {                                                            \
  92   ieee854_float128_shape_type sh_u;                             \
  93   sh_u.value = (d);                                             \
  94   sh_u.parts64.msw = (v);                                       \
  95   (d) = sh_u.value;                                             \
  96 } while (0)
  97
  98 /* Get the least significant 64 bits of a _Float128 mantissa.  */
  99
 100 # define GET_FLOAT128_LSW64(v,d)                                \
 101 do {                                                            \
 102   ieee854_float128_shape_type sh_u;                             \
 103   sh_u.value = (d);                                             \
 104   (v) = sh_u.parts64.lsw;                                       \
 105 } while (0)
 106
 107 /* Likewise, some helper macros which are exposed via ieee754.h for
 108    C99 real types, but not _Float128.  */
 109
 110 union ieee854_float128
 111   {
 112     _Float128 d;
 113
 114     /* This is the IEEE 854 quad-precision format.  */
 115     struct
 116       {
 117         __FLT_EORDER6 (unsigned int, negative:1,
 118                                      exponent:15,
 119                                      mantissa0:16,
 120                                      mantissa1:32,
 121                                      mantissa2:32,
 122                                      mantissa3:32)
 123       } ieee;
 124
 125     /* This format makes it easier to see if a NaN is a signalling NaN.  */
 126     struct
 127       {
 128         __FLT_EORDER7 (unsigned int, negative:1,
 129                                      exponent:15,
 130                                      quiet_nan:1,
 131                                      mantissa0:15,
 132                                      mantissa1:32,
 133                                      mantissa2:32,
 134                                      mantissa3:32)
 135       } ieee_nan;
 136   };
 137
 138 #define IEEE854_FLOAT128_BIAS 0x3fff /* Added to exponent.  */
 139
 140 #endif