floatformat.h revision 33965 
1/* IEEE floating point support declarations, for GDB, the GNU Debugger.
2   Copyright (C) 1991 Free Software Foundation, Inc.
3
4This file is part of GDB.
5
6This program is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 2 of the License, or
9(at your option) any later version.
10
11This program is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with this program; if not, write to the Free Software
18Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
19
20#if !defined (FLOATFORMAT_H)
21#define FLOATFORMAT_H 1
22
23#include "ansidecl.h"
24
25/* A floatformat consists of a sign bit, an exponent and a mantissa.  Once the
26   bytes are concatenated according to the byteorder flag, then each of those
27   fields is contiguous.  We number the bits with 0 being the most significant
28   (i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field
29   contains with the *_start and *_len fields.  */
30
31enum floatformat_byteorders { floatformat_little, floatformat_big };
32
33enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no };
34
35struct floatformat
36{
37  enum floatformat_byteorders byteorder;
38  unsigned int totalsize;	/* Total size of number in bits */
39
40  /* Sign bit is always one bit long.  1 means negative, 0 means positive.  */
41  unsigned int sign_start;
42
43  unsigned int exp_start;
44  unsigned int exp_len;
45  /* Amount added to "true" exponent.  0x3fff for many IEEE extendeds.  */
46  unsigned int exp_bias;
47  /* Exponent value which indicates NaN.  This is the actual value stored in
48     the float, not adjusted by the exp_bias.  This usually consists of all
49     one bits.  */
50  unsigned int exp_nan;
51
52  unsigned int man_start;
53  unsigned int man_len;
54
55  /* Is the integer bit explicit or implicit?  */
56  enum floatformat_intbit intbit;
57};
58
59/* floatformats for IEEE single and double, big and little endian.  */
60
61extern const struct floatformat floatformat_ieee_single_big;
62extern const struct floatformat floatformat_ieee_single_little;
63extern const struct floatformat floatformat_ieee_double_big;
64extern const struct floatformat floatformat_ieee_double_little;
65
66/* floatformats for various extendeds.  */
67
68extern const struct floatformat floatformat_i387_ext;
69extern const struct floatformat floatformat_m68881_ext;
70extern const struct floatformat floatformat_i960_ext;
71extern const struct floatformat floatformat_m88110_ext;
72extern const struct floatformat floatformat_arm_ext;
73
74/* Convert from FMT to a double.
75   FROM is the address of the extended float.
76   Store the double in *TO.  */
77
78extern void
79floatformat_to_double PARAMS ((const struct floatformat *, char *, double *));
80
81/* The converse: convert the double *FROM to FMT
82   and store where TO points.  */
83
84extern void
85floatformat_from_double PARAMS ((const struct floatformat *,
86				 double *, char *));
87
88#endif	/* defined (FLOATFORMAT_H) */
89