1  /* Manipulation of the bit representation of 'long double' quantities.
       2     Copyright (C) 1999-2023 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     <https://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     four 32 bit ints or two 64 bit ints.  */
      27  
      28  #if __FLOAT_WORD_ORDER == __BIG_ENDIAN
      29  
      30  typedef union
      31  {
      32    long double value;
      33    struct
      34    {
      35      uint64_t msw;
      36      uint64_t lsw;
      37    } parts64;
      38    struct
      39    {
      40      uint32_t w0, w1, w2, w3;
      41    } parts32;
      42  } ieee854_long_double_shape_type;
      43  
      44  #endif
      45  
      46  #if __FLOAT_WORD_ORDER == __LITTLE_ENDIAN
      47  
      48  typedef union
      49  {
      50    long double value;
      51    struct
      52    {
      53      uint64_t lsw;
      54      uint64_t msw;
      55    } parts64;
      56    struct
      57    {
      58      uint32_t w3, w2, w1, w0;
      59    } parts32;
      60  } ieee854_long_double_shape_type;
      61  
      62  #endif
      63  
      64  /* Get two 64 bit ints from a long double.  */
      65  
      66  #define GET_LDOUBLE_WORDS64(ix0,ix1,d)				\
      67  do {								\
      68    ieee854_long_double_shape_type qw_u;				\
      69    qw_u.value = (d);						\
      70    (ix0) = qw_u.parts64.msw;					\
      71    (ix1) = qw_u.parts64.lsw;					\
      72  } while (0)
      73  
      74  /* Set a long double from two 64 bit ints.  */
      75  
      76  #define SET_LDOUBLE_WORDS64(d,ix0,ix1)				\
      77  do {								\
      78    ieee854_long_double_shape_type qw_u;				\
      79    qw_u.parts64.msw = (ix0);					\
      80    qw_u.parts64.lsw = (ix1);					\
      81    (d) = qw_u.value;						\
      82  } while (0)
      83  
      84  /* Get the more significant 64 bits of a long double mantissa.  */
      85  
      86  #define GET_LDOUBLE_MSW64(v,d)					\
      87  do {								\
      88    ieee854_long_double_shape_type sh_u;				\
      89    sh_u.value = (d);						\
      90    (v) = sh_u.parts64.msw;					\
      91  } while (0)
      92  
      93  /* Set the more significant 64 bits of a long double mantissa from an int.  */
      94  
      95  #define SET_LDOUBLE_MSW64(d,v)					\
      96  do {								\
      97    ieee854_long_double_shape_type sh_u;				\
      98    sh_u.value = (d);						\
      99    sh_u.parts64.msw = (v);					\
     100    (d) = sh_u.value;						\
     101  } while (0)
     102  
     103  /* Get the least significant 64 bits of a long double mantissa.  */
     104  
     105  #define GET_LDOUBLE_LSW64(v,d)					\
     106  do {								\
     107    ieee854_long_double_shape_type sh_u;				\
     108    sh_u.value = (d);						\
     109    (v) = sh_u.parts64.lsw;					\
     110  } while (0)
     111  
     112  /*
     113     On a platform already supporting a binary128 long double,
     114     _Float128 will alias to long double.  This transformation
     115     makes aliasing *l functions to *f128 trivial.
     116  */
     117  #define _Float128 long double
     118  #define L(x) x##L
     119  
     120  #endif /* math_ldbl.h */