stdlib/fpioconst.h

   1 /* Header file for constants used in floating point <-> decimal conversions.
   2 Copyright (C) 1995, 1996 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 Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 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 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #ifndef _FPIOCONST_H
  21 #define _FPIOCONST_H
  22
  23 #include <float.h>
  24 #include "gmp.h"
  25
  26
  27 /* These values are used by __printf_fp, where they are noncritical (if the
  28    value is not large enough, it will just be slower); and by
  29    strtof/strtod/strtold, where it is critical (it's used for overflow
  30    detection).
  31
  32    XXX These should be defined in <float.h>.  For the time being, we have the
  33    IEEE754 values here.  */
  34
  35 #define LDBL_MAX_10_EXP_LOG     12 /* = floor(log_2(LDBL_MAX_10_EXP)) */
  36 #define DBL_MAX_10_EXP_LOG      8 /* = floor(log_2(DBL_MAX_10_EXP)) */
  37 #define FLT_MAX_10_EXP_LOG      5 /* = floor(log_2(FLT_MAX_10_EXP)) */
  38
  39
  40 /* Table of powers of ten.  This is used by __printf_fp and by
  41    strtof/strtod/strtold.  */
  42 struct mp_power
  43   {
  44     const mp_limb_t *array;     /* The array with the number representation. */
  45     mp_size_t arraysize;        /* Size of the array.  */
  46     int p_expo;                 /* Exponent of the number 10^(2^i).  */
  47     int m_expo;                 /* Exponent of the number 10^-(2^i-1).  */
  48   };
  49 extern const struct mp_power _fpioconst_pow10[LDBL_MAX_10_EXP_LOG + 1];
  50
  51 /* The constants in the array `_fpioconst_pow10' have an offset.  */
  52 #if BITS_PER_MP_LIMB == 32
  53 # define _FPIO_CONST_OFFSET     2
  54 #else
  55 # define _FPIO_CONST_OFFSET     1
  56 #endif
  57
  58
  59 #endif  /* fpioconst.h */