[unix-history] / gnu / usr.bin / as / flonum.h

/* flonum.h - Floating point package
   Copyright (C) 1987 Free Software Foundation, Inc.

This file is part of GAS, the GNU Assembler.

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 1, or (at your option)
any later version.

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.

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, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/***********************************************************************\
*									*
*	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!			*
*									*
\***********************************************************************/
#if !defined(__STDC__) && !defined(const)
#define const /* empty */
#endif

#include "bignum.h"

/***********************************************************************\
*									*
*	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.		*
*									*
\***********************************************************************/

/* 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 int		exponent; /* base LITTLENUM_RADIX */
  char			sign;	/* '+' or '-' */
};

typedef struct FLONUM_STRUCT FLONUM_TYPE;


/***********************************************************************\
*									*
*	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).		*
*									*
\***********************************************************************/


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. */


/***********************************************************************\
*									*
*	Declare worker functions.					*
*									*
\***********************************************************************/

void	flonum_multip();
void	flonum_copy();
void	flonum_print();
char *	flonum_get();		/* Returns "" or error string. */
void	flonum_normal();

int	atof_generic();


/***********************************************************************\
*									*
*	Declare error codes.						*
*									*
\***********************************************************************/

#define ERROR_EXPONENT_OVERFLOW (2)

/* end: flonum.h */
Commit	Line	Data
7b374118 NW	1	/* flonum.h - Floating point package
	2	Copyright (C) 1987 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 1, 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
	18	the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
	19
	20	/***********************************************************************\
	21	* *
	22	* Arbitrary-precision floating point arithmetic. *
	23	* *
	24	* *
	25	* Notation: a floating point number is expressed as *
	26	* MANTISSA * (2 ** EXPONENT). *
	27	* *
	28	* If this offends more traditional mathematicians, then *
	29	* please tell me your nomenclature for flonums! *
	30	* *
	31	\***********************************************************************/
	32	#if !defined(__STDC__) && !defined(const)
	33	#define const /* empty */
	34	#endif
	35
	36	#include "bignum.h"
	37
	38	/***********************************************************************\
	39	* *
	40	* Variable precision floating point numbers. *
	41	* *
	42	* Exponent is the place value of the low littlenum. E.g.: *
	43	* If 0: low points to the units littlenum. *
	44	* If 1: low points to the LITTLENUM_RADIX littlenum. *
	45	* If -1: low points to the 1/LITTLENUM_RADIX littlenum. *
	46	* *
	47	\***********************************************************************/
	48
	49	/* JF: A sign value of 0 means we have been asked to assemble NaN
	50	A sign value of 'P' means we've been asked to assemble +Inf
	51	A sign value of 'N' means we've been asked to assemble -Inf
	52	*/
	53	struct FLONUM_STRUCT
	54	{
	55	LITTLENUM_TYPE * low; /* low order littlenum of a bignum */
	56	LITTLENUM_TYPE * high; /* high order littlenum of a bignum */
	57	LITTLENUM_TYPE * leader; /* -> 1st non-zero littlenum */
	58	/* If flonum is 0.0, leader==low-1 */
	59	long int exponent; /* base LITTLENUM_RADIX */
	60	char sign; /* '+' or '-' */
	61	};
	62
	63	typedef struct FLONUM_STRUCT FLONUM_TYPE;
	64
65
66	/***********************************************************************\
67	* *
68	* Since we can (& do) meet with exponents like 10^5000, it *
69	* is silly to make a table of ~ 10,000 entries, one for each *
70	* power of 10. We keep a table where item [n] is a struct *
71	* FLONUM_FLOATING_POINT representing 10^(2^n). We then *
72	* multiply appropriate entries from this table to get any *
73	* particular power of 10. For the example of 10^5000, a table *
74	* of just 25 entries suffices: 10^(2^-12)...10^(2^+12). *
75	* *
76	\***********************************************************************/
77
78
79	extern const FLONUM_TYPE flonum_positive_powers_of_ten[];
80	extern const FLONUM_TYPE flonum_negative_powers_of_ten[];
81	extern const int table_size_of_flonum_powers_of_ten;
82	/* Flonum_XXX_powers_of_ten[] table has */
83	/* legal indices from 0 to */
84	/* + this number inclusive. */
85
86
87
88	/***********************************************************************\
89	* *
90	* Declare worker functions. *
91	* *
92	\***********************************************************************/
93
94	void flonum_multip();
95	void flonum_copy();
96	void flonum_print();
97	char * flonum_get(); /* Returns "" or error string. */
98	void flonum_normal();
99
100	int atof_generic();
101
102
103	/***********************************************************************\
104	* *
105	* Declare error codes. *
106	* *
107	\***********************************************************************/
108
109	#define ERROR_EXPONENT_OVERFLOW (2)
110
111	/* end: flonum.h */