| 1 | /* flonum.h - Floating point package
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| 2 | Copyright 1987, 1990, 1991, 1992, 1994, 1996, 2000
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| 3 | Free Software Foundation, Inc.
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| 4 |
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| 5 | This file is part of GAS, the GNU Assembler.
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| 6 |
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| 7 | GAS is free software; you can redistribute it and/or modify
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| 8 | it under the terms of the GNU General Public License as published by
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| 9 | the Free Software Foundation; either version 2, or (at your option)
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| 10 | any later version.
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| 11 |
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| 12 | GAS is distributed in the hope that it will be useful,
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | GNU General Public License for more details.
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| 16 |
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| 17 | You should have received a copy of the GNU General Public License
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| 18 | along with GAS; see the file COPYING. If not, write to the Free
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| 19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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| 20 | 02111-1307, USA. */
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| 21 |
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| 22 | /***********************************************************************\
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| 23 | * *
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| 24 | * Arbitrary-precision floating point arithmetic. *
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| 25 | * *
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| 26 | * *
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| 27 | * Notation: a floating point number is expressed as *
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| 28 | * MANTISSA * (2 ** EXPONENT). *
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| 29 | * *
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| 30 | * If this offends more traditional mathematicians, then *
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| 31 | * please tell me your nomenclature for flonums! *
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| 32 | * *
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| 33 | \***********************************************************************/
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| 34 |
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| 35 | #include "bignum.h"
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| 36 |
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| 37 | /***********************************************************************\
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| 38 | * *
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| 39 | * Variable precision floating point numbers. *
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| 40 | * *
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| 41 | * Exponent is the place value of the low littlenum. E.g.: *
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| 42 | * If 0: low points to the units littlenum. *
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| 43 | * If 1: low points to the LITTLENUM_RADIX littlenum. *
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| 44 | * If -1: low points to the 1/LITTLENUM_RADIX littlenum. *
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| 45 | * *
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| 46 | \***********************************************************************/
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| 47 |
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| 48 | /* JF: A sign value of 0 means we have been asked to assemble NaN
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| 49 | A sign value of 'P' means we've been asked to assemble +Inf
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| 50 | A sign value of 'N' means we've been asked to assemble -Inf
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| 51 | */
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| 52 | struct FLONUM_STRUCT {
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| 53 | LITTLENUM_TYPE *low; /* low order littlenum of a bignum */
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| 54 | LITTLENUM_TYPE *high; /* high order littlenum of a bignum */
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| 55 | LITTLENUM_TYPE *leader; /* -> 1st non-zero littlenum */
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| 56 | /* If flonum is 0.0, leader==low-1 */
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| 57 | long exponent; /* base LITTLENUM_RADIX */
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| 58 | char sign; /* '+' or '-' */
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| 59 | };
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| 60 |
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| 61 | typedef struct FLONUM_STRUCT FLONUM_TYPE;
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| 62 |
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| 63 | /***********************************************************************\
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| 64 | * *
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| 65 | * Since we can (& do) meet with exponents like 10^5000, it *
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| 66 | * is silly to make a table of ~ 10,000 entries, one for each *
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| 67 | * power of 10. We keep a table where item [n] is a struct *
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| 68 | * FLONUM_FLOATING_POINT representing 10^(2^n). We then *
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| 69 | * multiply appropriate entries from this table to get any *
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| 70 | * particular power of 10. For the example of 10^5000, a table *
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| 71 | * of just 25 entries suffices: 10^(2^-12)...10^(2^+12). *
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| 72 | * *
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| 73 | \***********************************************************************/
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| 74 |
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| 75 | extern const FLONUM_TYPE flonum_positive_powers_of_ten[];
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| 76 | extern const FLONUM_TYPE flonum_negative_powers_of_ten[];
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| 77 | extern const int table_size_of_flonum_powers_of_ten;
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| 78 | /* Flonum_XXX_powers_of_ten[] table has legal indices from 0 to
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| 79 | + this number inclusive. */
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| 80 |
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| 81 | /***********************************************************************\
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| 82 | * *
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| 83 | * Declare worker functions. *
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| 84 | * *
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| 85 | \***********************************************************************/
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| 86 |
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| 87 | int atof_generic PARAMS ((char **address_of_string_pointer,
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| 88 | const char *string_of_decimal_marks,
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| 89 | const char *string_of_decimal_exponent_marks,
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| 90 | FLONUM_TYPE * address_of_generic_floating_point_number));
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| 91 |
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| 92 | void flonum_copy PARAMS ((FLONUM_TYPE * in, FLONUM_TYPE * out));
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| 93 | void flonum_multip PARAMS ((const FLONUM_TYPE * a, const FLONUM_TYPE * b,
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| 94 | FLONUM_TYPE * product));
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| 95 |
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| 96 | /***********************************************************************\
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| 97 | * *
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| 98 | * Declare error codes. *
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| 99 | * *
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| 100 | \***********************************************************************/
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| 101 |
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| 102 | #define ERROR_EXPONENT_OVERFLOW (2)
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