floatformat.h revision 38889 
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
31/* What is the order of the bytes. */
32
33enum floatformat_byteorders {
34
35  /* Standard little endian byte order.
36     EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */
37
38  floatformat_little,
39
40  /* Standard big endian byte order.
41     EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */
42
43  floatformat_big,
44
45  /* Little endian byte order but big endian word order.
46     EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */
47
48  floatformat_littlebyte_bigword
49
50};
51
52enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no };
53
54struct floatformat
55{
56  enum floatformat_byteorders byteorder;
57  unsigned int totalsize;	/* Total size of number in bits */
58
59  /* Sign bit is always one bit long.  1 means negative, 0 means positive.  */
60  unsigned int sign_start;
61
62  unsigned int exp_start;
63  unsigned int exp_len;
64  /* Amount added to "true" exponent.  0x3fff for many IEEE extendeds.  */
65  unsigned int exp_bias;
66  /* Exponent value which indicates NaN.  This is the actual value stored in
67     the float, not adjusted by the exp_bias.  This usually consists of all
68     one bits.  */
69  unsigned int exp_nan;
70
71  unsigned int man_start;
72  unsigned int man_len;
73
74  /* Is the integer bit explicit or implicit?  */
75  enum floatformat_intbit intbit;
76};
77
78/* floatformats for IEEE single and double, big and little endian.  */
79
80extern const struct floatformat floatformat_ieee_single_big;
81extern const struct floatformat floatformat_ieee_single_little;
82extern const struct floatformat floatformat_ieee_double_big;
83extern const struct floatformat floatformat_ieee_double_little;
84
85/* floatformat for ARM IEEE double, little endian bytes and big endian words */
86
87extern const struct floatformat floatformat_ieee_double_littlebyte_bigword;
88
89/* floatformats for various extendeds.  */
90
91extern const struct floatformat floatformat_i387_ext;
92extern const struct floatformat floatformat_m68881_ext;
93extern const struct floatformat floatformat_i960_ext;
94extern const struct floatformat floatformat_m88110_ext;
95extern const struct floatformat floatformat_arm_ext;
96
97/* Convert from FMT to a double.
98   FROM is the address of the extended float.
99   Store the double in *TO.  */
100
101extern void
102floatformat_to_double PARAMS ((const struct floatformat *, char *, double *));
103
104/* The converse: convert the double *FROM to FMT
105   and store where TO points.  */
106
107extern void
108floatformat_from_double PARAMS ((const struct floatformat *,
109				 double *, char *));
110
111#endif	/* defined (FLOATFORMAT_H) */
112