floatformat.h   [plain text]

/* IEEE floating point support declarations, for GDB, the GNU Debugger.
   Copyright (C) 1991 Free Software Foundation, Inc.

This file is part of GDB.

This program 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 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#if !defined (FLOATFORMAT_H)

#include "ansidecl.h"

/* A floatformat consists of a sign bit, an exponent and a mantissa.  Once the
   bytes are concatenated according to the byteorder flag, then each of those
   fields is contiguous.  We number the bits with 0 being the most significant
   (i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field
   contains with the *_start and *_len fields.  */

/* What is the order of the bytes. */

enum floatformat_byteorders {

  /* Standard little endian byte order.
     EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */


  /* Standard big endian byte order.
     EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */


  /* Little endian byte order but big endian word order.
     EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */



enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no };

struct floatformat
  enum floatformat_byteorders byteorder;
  unsigned int totalsize;	/* Total size of number in bits */

  /* Sign bit is always one bit long.  1 means negative, 0 means positive.  */
  unsigned int sign_start;

  unsigned int exp_start;
  unsigned int exp_len;
  /* Amount added to "true" exponent.  0x3fff for many IEEE extendeds.  */
  unsigned int exp_bias;
  /* Exponent value which indicates NaN.  This is the actual value stored in
     the float, not adjusted by the exp_bias.  This usually consists of all
     one bits.  */
  unsigned int exp_nan;

  unsigned int man_start;
  unsigned int man_len;

  /* Is the integer bit explicit or implicit?  */
  enum floatformat_intbit intbit;

/* floatformats for IEEE single and double, big and little endian.  */

extern const struct floatformat floatformat_ieee_single_big;
extern const struct floatformat floatformat_ieee_single_little;
extern const struct floatformat floatformat_ieee_double_big;
extern const struct floatformat floatformat_ieee_double_little;

/* floatformat for ARM IEEE double, little endian bytes and big endian words */

extern const struct floatformat floatformat_ieee_double_littlebyte_bigword;

/* floatformats for various extendeds.  */

extern const struct floatformat floatformat_i387_ext;
extern const struct floatformat floatformat_m68881_ext;
extern const struct floatformat floatformat_i960_ext;
extern const struct floatformat floatformat_m88110_ext;
extern const struct floatformat floatformat_arm_ext;

/* Convert from FMT to a double.
   FROM is the address of the extended float.
   Store the double in *TO.  */

extern void
floatformat_to_double PARAMS ((const struct floatformat *, char *, double *));

/* The converse: convert the double *FROM to FMT
   and store where TO points.  */

extern void
floatformat_from_double PARAMS ((const struct floatformat *,
				 double *, char *));

#endif	/* defined (FLOATFORMAT_H) */