1  /* Manipulation of the bit representation of 'long double' quantities.
       2     Copyright (C) 2000-2023 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     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      unsigned int empty0:32;
      36      int sign_exponent:16;
      37      unsigned int empty1:16;
      38      uint32_t msw;
      39      uint32_t lsw;
      40    } parts;
      41  } ieee_long_double_shape_type;
      42  
      43  #endif
      44  
      45  #if __FLOAT_WORD_ORDER == __LITTLE_ENDIAN
      46  
      47  typedef union
      48  {
      49    long double value;
      50    struct
      51    {
      52      uint32_t lsw;
      53      uint32_t msw;
      54      int sign_exponent:16;
      55      unsigned int empty1:16;
      56      unsigned int empty0:32;
      57    } parts;
      58  } ieee_long_double_shape_type;
      59  
      60  #endif
      61  
      62  /* Get three 32 bit ints from a double.  */
      63  
      64  #define GET_LDOUBLE_WORDS(exp,ix0,ix1,d)			\
      65  do {								\
      66    ieee_long_double_shape_type ew_u;				\
      67    ew_u.value = (d);						\
      68    (exp) = ew_u.parts.sign_exponent;				\
      69    (ix0) = ew_u.parts.msw;					\
      70    (ix1) = ew_u.parts.lsw;					\
      71  } while (0)
      72  
      73  /* Set a double from two 32 bit ints.  */
      74  
      75  #define SET_LDOUBLE_WORDS(d,exp,ix0,ix1)			\
      76  do {								\
      77    ieee_long_double_shape_type iw_u;				\
      78    iw_u.parts.sign_exponent = (exp);				\
      79    iw_u.parts.msw = (ix0);					\
      80    iw_u.parts.lsw = (ix1);					\
      81    (d) = iw_u.value;						\
      82  } while (0)
      83  
      84  /* Get the more significant 32 bits of a long double mantissa.  */
      85  
      86  #define GET_LDOUBLE_MSW(v,d)					\
      87  do {								\
      88    ieee_long_double_shape_type sh_u;				\
      89    sh_u.value = (d);						\
      90    (v) = sh_u.parts.msw;						\
      91  } while (0)
      92  
      93  /* Set the more significant 32 bits of a long double mantissa from an int.  */
      94  
      95  #define SET_LDOUBLE_MSW(d,v)					\
      96  do {								\
      97    ieee_long_double_shape_type sh_u;				\
      98    sh_u.value = (d);						\
      99    sh_u.parts.msw = (v);						\
     100    (d) = sh_u.value;						\
     101  } while (0)
     102  
     103  /* Get int from the exponent of a long double.  */
     104  
     105  #define GET_LDOUBLE_EXP(exp,d)					\
     106  do {								\
     107    ieee_long_double_shape_type ge_u;				\
     108    ge_u.value = (d);						\
     109    (exp) = ge_u.parts.sign_exponent;				\
     110  } while (0)
     111  
     112  /* Set exponent of a long double from an int.  */
     113  
     114  #define SET_LDOUBLE_EXP(d,exp)					\
     115  do {								\
     116    ieee_long_double_shape_type se_u;				\
     117    se_u.value = (d);						\
     118    se_u.parts.sign_exponent = (exp);				\
     119    (d) = se_u.value;						\
     120  } while (0)
     121  
     122  #endif /* math_ldbl.h */