stdlib/fpioconst.h

   1 /* Header file for constants used in floating point <-> decimal conversions.
   2    Copyright (C) 1995, 1996, 1997, 1998, 1999 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 not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #ifndef _FPIOCONST_H
  21 #define _FPIOCONST_H
  22
  23 #include <float.h>
  24 #include <math.h>
  25 #include "gmp.h"
  26
  27
  28 /* These values are used by __printf_fp, where they are noncritical (if the
  29    value is not large enough, it will just be slower); and by
  30    strtof/strtod/strtold, where it is critical (it's used for overflow
  31    detection).
  32
  33    XXX These should be defined in <float.h>.  For the time being, we have the
  34    IEEE754 values here.  */
  35
  36 #ifndef __NO_LONG_DOUBLE_MATH
  37 # define LDBL_MAX_10_EXP_LOG    12 /* = floor(log_2(LDBL_MAX_10_EXP)) */
  38 #else
  39 # define LDBL_MAX_10_EXP_LOG    8 /* = floor(log_2(LDBL_MAX_10_EXP)) */
  40 #endif
  41 #define DBL_MAX_10_EXP_LOG      8 /* = floor(log_2(DBL_MAX_10_EXP)) */
  42 #define FLT_MAX_10_EXP_LOG      5 /* = floor(log_2(FLT_MAX_10_EXP)) */
  43
  44
  45 /* Table of powers of ten.  This is used by __printf_fp and by
  46    strtof/strtod/strtold.  */
  47 struct mp_power
  48   {
  49     const mp_limb_t *array;     /* The array with the number representation. */
  50     mp_size_t arraysize;        /* Size of the array.  */
  51     int p_expo;                 /* Exponent of the number 10^(2^i).  */
  52     int m_expo;                 /* Exponent of the number 10^-(2^i-1).  */
  53   };
  54 extern const struct mp_power _fpioconst_pow10[LDBL_MAX_10_EXP_LOG + 1];
  55
  56 /* The constants in the array `_fpioconst_pow10' have an offset.  */
  57 #if BITS_PER_MP_LIMB == 32
  58 # define _FPIO_CONST_OFFSET     2
  59 #else
  60 # define _FPIO_CONST_OFFSET     1
  61 #endif
  62
  63
  64 #endif  /* fpioconst.h */