1/* flonum.h - Floating point package
2   Copyright (C) 1987-2017 Free Software Foundation, Inc.
3
4   This file is part of GAS, the GNU Assembler.
5
6   GAS is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3, or (at your option)
9   any later version.
10
11   GAS is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with GAS; see the file COPYING.  If not, write to the Free
18   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
19   02110-1301, USA.  */
20
21/***********************************************************************\
22 *									*
23 *	Arbitrary-precision floating point arithmetic.			*
24 *									*
25 *									*
26 *	Notation: a floating point number is expressed as		*
27 *	MANTISSA * (2 ** EXPONENT).					*
28 *									*
29 *	If this offends more traditional mathematicians, then		*
30 *	please tell me your nomenclature for flonums!			*
31 *									*
32 \***********************************************************************/
33
34#include "bignum.h"
35
36/***********************************************************************\
37 *									*
38 *	Variable precision floating point numbers.			*
39 *									*
40 *	Exponent is the place value of the low littlenum. E.g.:		*
41 *	If  0:  low points to the units             littlenum.		*
42 *	If  1:  low points to the LITTLENUM_RADIX   littlenum.		*
43 *	If -1:  low points to the 1/LITTLENUM_RADIX littlenum.		*
44 *									*
45 \***********************************************************************/
46
47/* JF:  A sign value of 0 means we have been asked to assemble NaN
48   A sign value of 'P' means we've been asked to assemble +Inf
49   A sign value of 'N' means we've been asked to assemble -Inf
50   */
51struct FLONUM_STRUCT {
52  LITTLENUM_TYPE *low;		/* low order littlenum of a bignum */
53  LITTLENUM_TYPE *high;		/* high order littlenum of a bignum */
54  LITTLENUM_TYPE *leader;	/* -> 1st non-zero littlenum */
55  /* If flonum is 0.0, leader==low-1 */
56  long exponent;		/* base LITTLENUM_RADIX */
57  char sign;			/* '+' or '-' */
58};
59
60typedef struct FLONUM_STRUCT FLONUM_TYPE;
61
62/***********************************************************************\
63 *									*
64 *	Since we can (& do) meet with exponents like 10^5000, it	*
65 *	is silly to make a table of ~ 10,000 entries, one for each	*
66 *	power of 10. We keep a table where item [n] is a struct		*
67 *	FLONUM_FLOATING_POINT representing 10^(2^n). We then		*
68 *	multiply appropriate entries from this table to get any		*
69 *	particular power of 10. For the example of 10^5000, a table	*
70 *	of just 25 entries suffices: 10^(2^-12)...10^(2^+12).		*
71 *									*
72 \***********************************************************************/
73
74extern const FLONUM_TYPE flonum_positive_powers_of_ten[];
75extern const FLONUM_TYPE flonum_negative_powers_of_ten[];
76extern const int table_size_of_flonum_powers_of_ten;
77/* Flonum_XXX_powers_of_ten[] table has legal indices from 0 to
78   + this number inclusive.  */
79
80/***********************************************************************\
81 *									*
82 *	Declare worker functions.					*
83 *									*
84 \***********************************************************************/
85
86int atof_generic (char **address_of_string_pointer,
87		  const char *string_of_decimal_marks,
88		  const char *string_of_decimal_exponent_marks,
89		  FLONUM_TYPE * address_of_generic_floating_point_number);
90
91void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out);
92void flonum_multip (const FLONUM_TYPE * a, const FLONUM_TYPE * b,
93		    FLONUM_TYPE * product);
94
95/***********************************************************************\
96 *									*
97 *	Declare error codes.						*
98 *									*
99 \***********************************************************************/
100
101#define ERROR_EXPONENT_OVERFLOW (2)
102