sysdeps/ieee754/ldbl-96/math_ldbl.h

   1 /* Manipulation of the bit representation of 'long double' quantities.
   2    Copyright (C) 1999-2019 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
  19 #ifndef _MATH_LDBL_H_
  20 #define _MATH_LDBL_H_ 1
  21
  22 #include <stdint.h>
  23 #include <endian.h>
  24
  25 /* A union which permits us to convert between a long double and
  26    three 32 bit ints.  */
  27
  28 #if __FLOAT_WORD_ORDER == __BIG_ENDIAN
  29
  30 typedef union
  31 {
  32   long double value;
  33   struct
  34   {
  35     int sign_exponent:16;
  36     unsigned int empty:16;
  37     uint32_t msw;
  38     uint32_t lsw;
  39   } parts;
  40 } ieee_long_double_shape_type;
  41
  42 #endif
  43
  44 #if __FLOAT_WORD_ORDER == __LITTLE_ENDIAN
  45
  46 typedef union
  47 {
  48   long double value;
  49   struct
  50   {
  51     uint32_t lsw;
  52     uint32_t msw;
  53     int sign_exponent:16;
  54     unsigned int empty:16;
  55   } parts;
  56 } ieee_long_double_shape_type;
  57
  58 #endif
  59
  60 /* Get three 32 bit ints from a double.  */
  61
  62 #define GET_LDOUBLE_WORDS(exp,ix0,ix1,d)                        \
  63 do {                                                            \
  64   ieee_long_double_shape_type ew_u;                             \
  65   ew_u.value = (d);                                             \
  66   (exp) = ew_u.parts.sign_exponent;                             \
  67   (ix0) = ew_u.parts.msw;                                       \
  68   (ix1) = ew_u.parts.lsw;                                       \
  69 } while (0)
  70
  71 /* Set a double from two 32 bit ints.  */
  72
  73 #define SET_LDOUBLE_WORDS(d,exp,ix0,ix1)                        \
  74 do {                                                            \
  75   ieee_long_double_shape_type iw_u;                             \
  76   iw_u.parts.sign_exponent = (exp);                             \
  77   iw_u.parts.msw = (ix0);                                       \
  78   iw_u.parts.lsw = (ix1);                                       \
  79   (d) = iw_u.value;                                             \
  80 } while (0)
  81
  82 /* Get the more significant 32 bits of a long double mantissa.  */
  83
  84 #define GET_LDOUBLE_MSW(v,d)                                    \
  85 do {                                                            \
  86   ieee_long_double_shape_type sh_u;                             \
  87   sh_u.value = (d);                                             \
  88   (v) = sh_u.parts.msw;                                         \
  89 } while (0)
  90
  91 /* Set the more significant 32 bits of a long double mantissa from an int.  */
  92
  93 #define SET_LDOUBLE_MSW(d,v)                                    \
  94 do {                                                            \
  95   ieee_long_double_shape_type sh_u;                             \
  96   sh_u.value = (d);                                             \
  97   sh_u.parts.msw = (v);                                         \
  98   (d) = sh_u.value;                                             \
  99 } while (0)
 100
 101 /* Get int from the exponent of a long double.  */
 102
 103 #define GET_LDOUBLE_EXP(exp,d)                                  \
 104 do {                                                            \
 105   ieee_long_double_shape_type ge_u;                             \
 106   ge_u.value = (d);                                             \
 107   (exp) = ge_u.parts.sign_exponent;                             \
 108 } while (0)
 109
 110 /* Set exponent of a long double from an int.  */
 111
 112 #define SET_LDOUBLE_EXP(d,exp)                                  \
 113 do {                                                            \
 114   ieee_long_double_shape_type se_u;                             \
 115   se_u.value = (d);                                             \
 116   se_u.parts.sign_exponent = (exp);                             \
 117   (d) = se_u.value;                                             \
 118 } while (0)
 119
 120 #endif /* math_ldbl.h */