/* flonum.h - Floating point package Copyright 1987, 1990, 1991, 1992, 1994, 1996, 2000 Free Software Foundation, Inc. This file is part of GAS, the GNU Assembler. GAS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GAS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GAS; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /***********************************************************************\ * * * Arbitrary-precision floating point arithmetic. * * * * * * Notation: a floating point number is expressed as * * MANTISSA * (2 ** EXPONENT). * * * * If this offends more traditional mathematicians, then * * please tell me your nomenclature for flonums! * * * \***********************************************************************/ #include "bignum.h" /***********************************************************************\ * * * Variable precision floating point numbers. * * * * Exponent is the place value of the low littlenum. E.g.: * * If 0: low points to the units littlenum. * * If 1: low points to the LITTLENUM_RADIX littlenum. * * If -1: low points to the 1/LITTLENUM_RADIX littlenum. * * * \***********************************************************************/ /* JF: A sign value of 0 means we have been asked to assemble NaN A sign value of 'P' means we've been asked to assemble +Inf A sign value of 'N' means we've been asked to assemble -Inf */ struct FLONUM_STRUCT { LITTLENUM_TYPE *low; /* low order littlenum of a bignum */ LITTLENUM_TYPE *high; /* high order littlenum of a bignum */ LITTLENUM_TYPE *leader; /* -> 1st non-zero littlenum */ /* If flonum is 0.0, leader==low-1 */ long exponent; /* base LITTLENUM_RADIX */ char sign; /* '+' or '-' */ }; typedef struct FLONUM_STRUCT FLONUM_TYPE; /***********************************************************************\ * * * Since we can (& do) meet with exponents like 10^5000, it * * is silly to make a table of ~ 10,000 entries, one for each * * power of 10. We keep a table where item [n] is a struct * * FLONUM_FLOATING_POINT representing 10^(2^n). We then * * multiply appropriate entries from this table to get any * * particular power of 10. For the example of 10^5000, a table * * of just 25 entries suffices: 10^(2^-12)...10^(2^+12). * * * \***********************************************************************/ extern const FLONUM_TYPE flonum_positive_powers_of_ten[]; extern const FLONUM_TYPE flonum_negative_powers_of_ten[]; extern const int table_size_of_flonum_powers_of_ten; /* Flonum_XXX_powers_of_ten[] table has legal indices from 0 to + this number inclusive. */ /***********************************************************************\ * * * Declare worker functions. * * * \***********************************************************************/ int atof_generic (char **address_of_string_pointer, const char *string_of_decimal_marks, const char *string_of_decimal_exponent_marks, FLONUM_TYPE * address_of_generic_floating_point_number); void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out); void flonum_multip (const FLONUM_TYPE * a, const FLONUM_TYPE * b, FLONUM_TYPE * product); /***********************************************************************\ * * * Declare error codes. * * * \***********************************************************************/ #define ERROR_EXPONENT_OVERFLOW (2)