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julius |
/* flonum.h - Floating point package
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Copyright 1987, 1990, 1991, 1992, 1994, 1996, 2000, 2003, 2005, 2007
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Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
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02110-1301, USA. */
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/***********************************************************************\
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* *
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* Arbitrary-precision floating point arithmetic. *
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* *
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* *
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* Notation: a floating point number is expressed as *
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* MANTISSA * (2 ** EXPONENT). *
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* *
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* If this offends more traditional mathematicians, then *
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* please tell me your nomenclature for flonums! *
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* *
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\***********************************************************************/
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#include "bignum.h"
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/***********************************************************************\
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* *
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* Variable precision floating point numbers. *
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* *
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* Exponent is the place value of the low littlenum. E.g.: *
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* If 0: low points to the units littlenum. *
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* If 1: low points to the LITTLENUM_RADIX littlenum. *
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* If -1: low points to the 1/LITTLENUM_RADIX littlenum. *
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* *
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\***********************************************************************/
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/* JF: A sign value of 0 means we have been asked to assemble NaN
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A sign value of 'P' means we've been asked to assemble +Inf
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A sign value of 'N' means we've been asked to assemble -Inf
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*/
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struct FLONUM_STRUCT {
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LITTLENUM_TYPE *low; /* low order littlenum of a bignum */
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LITTLENUM_TYPE *high; /* high order littlenum of a bignum */
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LITTLENUM_TYPE *leader; /* -> 1st non-zero littlenum */
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/* If flonum is 0.0, leader==low-1 */
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long exponent; /* base LITTLENUM_RADIX */
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char sign; /* '+' or '-' */
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};
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typedef struct FLONUM_STRUCT FLONUM_TYPE;
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/***********************************************************************\
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* *
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* Since we can (& do) meet with exponents like 10^5000, it *
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* is silly to make a table of ~ 10,000 entries, one for each *
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* power of 10. We keep a table where item [n] is a struct *
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* FLONUM_FLOATING_POINT representing 10^(2^n). We then *
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* multiply appropriate entries from this table to get any *
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* particular power of 10. For the example of 10^5000, a table *
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* of just 25 entries suffices: 10^(2^-12)...10^(2^+12). *
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* *
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\***********************************************************************/
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extern const FLONUM_TYPE flonum_positive_powers_of_ten[];
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extern const FLONUM_TYPE flonum_negative_powers_of_ten[];
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extern const int table_size_of_flonum_powers_of_ten;
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/* Flonum_XXX_powers_of_ten[] table has legal indices from 0 to
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+ this number inclusive. */
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/***********************************************************************\
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* *
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* Declare worker functions. *
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* *
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\***********************************************************************/
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int atof_generic (char **address_of_string_pointer,
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const char *string_of_decimal_marks,
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const char *string_of_decimal_exponent_marks,
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FLONUM_TYPE * address_of_generic_floating_point_number);
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void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out);
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void flonum_multip (const FLONUM_TYPE * a, const FLONUM_TYPE * b,
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FLONUM_TYPE * product);
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/***********************************************************************\
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* *
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* Declare error codes. *
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* *
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\***********************************************************************/
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#define ERROR_EXPONENT_OVERFLOW (2)
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