| 1 | /* flonum.h - Floating point package |
| 2 | Copyright 1987, 1990, 1991, 1992, 1994, 1996, 2000, 2003, 2007 |
| 3 | Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GAS, the GNU Assembler. |
| 6 | |
| 7 | GAS is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3, or (at your option) |
| 10 | any later version. |
| 11 | |
| 12 | GAS is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with GAS; see the file COPYING. If not, write to the Free |
| 19 | Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA |
| 20 | 02110-1301, USA. */ |
| 21 | |
| 22 | /***********************************************************************\ |
| 23 | * * |
| 24 | * Arbitrary-precision floating point arithmetic. * |
| 25 | * * |
| 26 | * * |
| 27 | * Notation: a floating point number is expressed as * |
| 28 | * MANTISSA * (2 ** EXPONENT). * |
| 29 | * * |
| 30 | * If this offends more traditional mathematicians, then * |
| 31 | * please tell me your nomenclature for flonums! * |
| 32 | * * |
| 33 | \***********************************************************************/ |
| 34 | |
| 35 | #include "bignum.h" |
| 36 | |
| 37 | /***********************************************************************\ |
| 38 | * * |
| 39 | * Variable precision floating point numbers. * |
| 40 | * * |
| 41 | * Exponent is the place value of the low littlenum. E.g.: * |
| 42 | * If 0: low points to the units littlenum. * |
| 43 | * If 1: low points to the LITTLENUM_RADIX littlenum. * |
| 44 | * If -1: low points to the 1/LITTLENUM_RADIX littlenum. * |
| 45 | * * |
| 46 | \***********************************************************************/ |
| 47 | |
| 48 | /* JF: A sign value of 0 means we have been asked to assemble NaN |
| 49 | A sign value of 'P' means we've been asked to assemble +Inf |
| 50 | A sign value of 'N' means we've been asked to assemble -Inf |
| 51 | */ |
| 52 | struct FLONUM_STRUCT { |
| 53 | LITTLENUM_TYPE *low; /* low order littlenum of a bignum */ |
| 54 | LITTLENUM_TYPE *high; /* high order littlenum of a bignum */ |
| 55 | LITTLENUM_TYPE *leader; /* -> 1st non-zero littlenum */ |
| 56 | /* If flonum is 0.0, leader==low-1 */ |
| 57 | long exponent; /* base LITTLENUM_RADIX */ |
| 58 | char sign; /* '+' or '-' */ |
| 59 | }; |
| 60 | |
| 61 | typedef struct FLONUM_STRUCT FLONUM_TYPE; |
| 62 | |
| 63 | /***********************************************************************\ |
| 64 | * * |
| 65 | * Since we can (& do) meet with exponents like 10^5000, it * |
| 66 | * is silly to make a table of ~ 10,000 entries, one for each * |
| 67 | * power of 10. We keep a table where item [n] is a struct * |
| 68 | * FLONUM_FLOATING_POINT representing 10^(2^n). We then * |
| 69 | * multiply appropriate entries from this table to get any * |
| 70 | * particular power of 10. For the example of 10^5000, a table * |
| 71 | * of just 25 entries suffices: 10^(2^-12)...10^(2^+12). * |
| 72 | * * |
| 73 | \***********************************************************************/ |
| 74 | |
| 75 | extern const FLONUM_TYPE flonum_positive_powers_of_ten[]; |
| 76 | extern const FLONUM_TYPE flonum_negative_powers_of_ten[]; |
| 77 | extern const int table_size_of_flonum_powers_of_ten; |
| 78 | /* Flonum_XXX_powers_of_ten[] table has legal indices from 0 to |
| 79 | + this number inclusive. */ |
| 80 | |
| 81 | /***********************************************************************\ |
| 82 | * * |
| 83 | * Declare worker functions. * |
| 84 | * * |
| 85 | \***********************************************************************/ |
| 86 | |
| 87 | int atof_generic (char **address_of_string_pointer, |
| 88 | const char *string_of_decimal_marks, |
| 89 | const char *string_of_decimal_exponent_marks, |
| 90 | FLONUM_TYPE * address_of_generic_floating_point_number); |
| 91 | |
| 92 | void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out); |
| 93 | void flonum_multip (const FLONUM_TYPE * a, const FLONUM_TYPE * b, |
| 94 | FLONUM_TYPE * product); |
| 95 | |
| 96 | /***********************************************************************\ |
| 97 | * * |
| 98 | * Declare error codes. * |
| 99 | * * |
| 100 | \***********************************************************************/ |
| 101 | |
| 102 | #define ERROR_EXPONENT_OVERFLOW (2) |