[deliverable/binutils-gdb.git] / gas / flonum.h

/* flonum.h - Floating point package
   Copyright (C) 1987-2020 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 3, 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, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, 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!			*
 *									*
 \***********************************************************************/

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

int atof_generic (char **address_of_string_pointer,
		  const char *string_of_decimal_marks,
		  const char *string_of_decimal_exponent_marks,
		  FLONUM_TYPE * address_of_generic_floating_point_number);

void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out);
void flonum_multip (const FLONUM_TYPE * a, const FLONUM_TYPE * b,
		    FLONUM_TYPE * product);

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

#define ERROR_EXPONENT_OVERFLOW (2)
Commit	Line	Data
	1	/* flonum.h - Floating point package
	2	Copyright (C) 1987-2020 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	*/
	51	struct 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
	60	typedef 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
	74	extern const FLONUM_TYPE flonum_positive_powers_of_ten[];
	75	extern const FLONUM_TYPE flonum_negative_powers_of_ten[];
	76	extern 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
	86	int 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
	91	void flonum_copy (FLONUM_TYPE * in, FLONUM_TYPE * out);
	92	void 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)