1  /* Macros for the implementation of *cvt functions, long double version.
       2     Copyright (C) 1996-2023 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  #include <float.h>
      20  
      21  #define FLOAT_TYPE long double
      22  #define FUNC_PREFIX q
      23  #define FLOAT_FMT_FLAG "L"
      24  #define FLOAT_NAME_EXT l
      25  #define FLOAT_MIN_10_EXP LDBL_MIN_10_EXP
      26  /* Actually we have to write (LDBL_DIG + log10 (LDBL_MAX_10_EXP)) but
      27     we don't have log10 available in the preprocessor.  Since we cannot
      28     assume anything on the used `long double' format be generous.  */
      29  #define MAXDIG (NDIGIT_MAX + 12)
      30  #define FCVT_MAXDIG (LDBL_MAX_10_EXP + MAXDIG)
      31  #if LDBL_MANT_DIG == 64
      32  # define NDIGIT_MAX 21
      33  #elif LDBL_MANT_DIG == 53
      34  # define NDIGIT_MAX 17
      35  #elif LDBL_MANT_DIG == 113
      36  # define NDIGIT_MAX 36
      37  #elif LDBL_MANT_DIG == 106
      38  # define NDIGIT_MAX 34
      39  #elif LDBL_MANT_DIG == 56
      40  # define NDIGIT_MAX 18
      41  #else
      42  /* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
      43     compile time constant here, so we cannot use it.  */
      44  # error "NDIGIT_MAX must be precomputed"
      45  # define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * LDBL_MANT_DIG + 1.0)))
      46  #endif
      47  #if LDBL_MIN_10_EXP == -37
      48  # define FLOAT_MIN_10_NORM	1.0e-37L
      49  #elif LDBL_MIN_10_EXP == -291
      50  # define FLOAT_MIN_10_NORM	1.0e-291L
      51  #elif LDBL_MIN_10_EXP == -307
      52  # define FLOAT_MIN_10_NORM	1.0e-307L
      53  #elif LDBL_MIN_10_EXP == -4931
      54  # define FLOAT_MIN_10_NORM	1.0e-4931L
      55  #else
      56  /* libc can't depend on libm.  */
      57  # error "FLOAT_MIN_10_NORM must be precomputed"
      58  # define FLOAT_MIN_10_NORM	exp10l (LDBL_MIN_10_EXP)
      59  #endif