1/* flonum.h - Floating point package
2   Copyright 1987, 1990, 1991, 1992, 1994, 1996, 2000, 2003
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 2, 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   */
52struct 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
61typedef 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
75extern const FLONUM_TYPE flonum_positive_powers_of_ten[];
76extern const FLONUM_TYPE flonum_negative_powers_of_ten[];
77extern 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
87int 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
92void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out);
93void 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)
103