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  1. /* flonum.h - Floating point package
  2.    Copyright (C) 1987-2015 Free Software Foundation, Inc.
  3.  
  4.    This file is part of GAS, the GNU Assembler.
  5.  
  6.    GAS is free software; you can redistribute it and/or modify
  7.    it under the terms of the GNU General Public License as published by
  8.    the Free Software Foundation; either version 3, or (at your option)
  9.    any later version.
  10.  
  11.    GAS is distributed in the hope that it will be useful,
  12.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14.    GNU General Public License for more details.
  15.  
  16.    You should have received a copy of the GNU General Public License
  17.    along with GAS; see the file COPYING.  If not, write to the Free
  18.    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  19.    02110-1301, USA.  */
  20.  
  21. /***********************************************************************\
  22.  *                                                                      *
  23.  *      Arbitrary-precision floating point arithmetic.                  *
  24.  *                                                                      *
  25.  *                                                                      *
  26.  *      Notation: a floating point number is expressed as               *
  27.  *      MANTISSA * (2 ** EXPONENT).                                     *
  28.  *                                                                      *
  29.  *      If this offends more traditional mathematicians, then           *
  30.  *      please tell me your nomenclature for flonums!                   *
  31.  *                                                                      *
  32.  \***********************************************************************/
  33.  
  34. #include "bignum.h"
  35.  
  36. /***********************************************************************\
  37.  *                                                                      *
  38.  *      Variable precision floating point numbers.                      *
  39.  *                                                                      *
  40.  *      Exponent is the place value of the low littlenum. E.g.:         *
  41.  *      If  0:  low points to the units             littlenum.          *
  42.  *      If  1:  low points to the LITTLENUM_RADIX   littlenum.          *
  43.  *      If -1:  low points to the 1/LITTLENUM_RADIX littlenum.          *
  44.  *                                                                      *
  45.  \***********************************************************************/
  46.  
  47. /* JF:  A sign value of 0 means we have been asked to assemble NaN
  48.    A sign value of 'P' means we've been asked to assemble +Inf
  49.    A sign value of 'N' means we've been asked to assemble -Inf
  50.    */
  51. struct FLONUM_STRUCT {
  52.   LITTLENUM_TYPE *low;          /* low order littlenum of a bignum */
  53.   LITTLENUM_TYPE *high;         /* high order littlenum of a bignum */
  54.   LITTLENUM_TYPE *leader;       /* -> 1st non-zero littlenum */
  55.   /* If flonum is 0.0, leader==low-1 */
  56.   long exponent;                /* base LITTLENUM_RADIX */
  57.   char sign;                    /* '+' or '-' */
  58. };
  59.  
  60. typedef struct FLONUM_STRUCT FLONUM_TYPE;
  61.  
  62. /***********************************************************************\
  63.  *                                                                      *
  64.  *      Since we can (& do) meet with exponents like 10^5000, it        *
  65.  *      is silly to make a table of ~ 10,000 entries, one for each      *
  66.  *      power of 10. We keep a table where item [n] is a struct         *
  67.  *      FLONUM_FLOATING_POINT representing 10^(2^n). We then            *
  68.  *      multiply appropriate entries from this table to get any         *
  69.  *      particular power of 10. For the example of 10^5000, a table     *
  70.  *      of just 25 entries suffices: 10^(2^-12)...10^(2^+12).           *
  71.  *                                                                      *
  72.  \***********************************************************************/
  73.  
  74. extern const FLONUM_TYPE flonum_positive_powers_of_ten[];
  75. extern const FLONUM_TYPE flonum_negative_powers_of_ten[];
  76. extern const int table_size_of_flonum_powers_of_ten;
  77. /* Flonum_XXX_powers_of_ten[] table has legal indices from 0 to
  78.    + this number inclusive.  */
  79.  
  80. /***********************************************************************\
  81.  *                                                                      *
  82.  *      Declare worker functions.                                       *
  83.  *                                                                      *
  84.  \***********************************************************************/
  85.  
  86. int atof_generic (char **address_of_string_pointer,
  87.                   const char *string_of_decimal_marks,
  88.                   const char *string_of_decimal_exponent_marks,
  89.                   FLONUM_TYPE * address_of_generic_floating_point_number);
  90.  
  91. void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out);
  92. void flonum_multip (const FLONUM_TYPE * a, const FLONUM_TYPE * b,
  93.                     FLONUM_TYPE * product);
  94.  
  95. /***********************************************************************\
  96.  *                                                                      *
  97.  *      Declare error codes.                                            *
  98.  *                                                                      *
  99.  \***********************************************************************/
  100.  
  101. #define ERROR_EXPONENT_OVERFLOW (2)
  102.