misc/efgcvt-ldbl-macros.h

   1 /* Macros for the implementation of *cvt functions, long double version.
   2    Copyright (C) 1996-2024 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