0,0 → 1,102 |
/* flonum.h - Floating point package |
Copyright 1987, 1990, 1991, 1992, 1994, 1996, 2000, 2003, 2005, 2007 |
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 |
it under the terms of the GNU General Public License as published by |
the Free Software Foundation; either version 3, or (at your option) |
any later version. |
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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. |
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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, 51 Franklin Street - Fifth Floor, Boston, MA |
02110-1301, USA. */ |
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/***********************************************************************\ |
* * |
* 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! * |
* * |
\***********************************************************************/ |
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#include "bignum.h" |
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/***********************************************************************\ |
* * |
* 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. * |
* * |
\***********************************************************************/ |
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/* 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 '-' */ |
}; |
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typedef struct FLONUM_STRUCT FLONUM_TYPE; |
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/***********************************************************************\ |
* * |
* 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). * |
* * |
\***********************************************************************/ |
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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. */ |
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/***********************************************************************\ |
* * |
* Declare worker functions. * |
* * |
\***********************************************************************/ |
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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); |
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void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out); |
void flonum_multip (const FLONUM_TYPE * a, const FLONUM_TYPE * b, |
FLONUM_TYPE * product); |
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/***********************************************************************\ |
* * |
* Declare error codes. * |
* * |
\***********************************************************************/ |
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#define ERROR_EXPONENT_OVERFLOW (2) |