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     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 */