source: trunk/libs/newlib/src/include/floatformat.h @ 666

Last change on this file since 666 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 5.8 KB
Line 
1/* IEEE floating point support declarations, for GDB, the GNU Debugger.
2   Copyright (C) 1991-2015 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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
19
20#if !defined (FLOATFORMAT_H)
21#define FLOATFORMAT_H 1
22
23#include "ansidecl.h"
24
25#ifdef __cplusplus
26extern "C" {
27#endif
28
29/* A floatformat consists of a sign bit, an exponent and a mantissa.  Once the
30   bytes are concatenated according to the byteorder flag, then each of those
31   fields is contiguous.  We number the bits with 0 being the most significant
32   (i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field
33   contains with the *_start and *_len fields.  */
34
35/* What is the order of the bytes?  */
36
37enum floatformat_byteorders {
38  /* Standard little endian byte order.
39     EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */
40  floatformat_little,
41
42  /* Standard big endian byte order.
43     EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */
44  floatformat_big,
45
46  /* Little endian byte order but big endian word order.
47     EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */
48  floatformat_littlebyte_bigword,
49
50  /* VAX byte order.  Little endian byte order with 16-bit words.  The
51     following example is an illustration of the byte order only; VAX
52     doesn't have a fully IEEE compliant floating-point format.
53     EX: 1.2345678e10 => 80 c5 00 00 06 42 e0 fe */
54  floatformat_vax
55};
56
57enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no };
58
59struct floatformat
60{
61  enum floatformat_byteorders byteorder;
62  unsigned int totalsize;       /* Total size of number in bits */
63
64  /* Sign bit is always one bit long.  1 means negative, 0 means positive.  */
65  unsigned int sign_start;
66
67  unsigned int exp_start;
68  unsigned int exp_len;
69  /* Bias added to a "true" exponent to form the biased exponent.  It
70     is intentionally signed as, otherwize, -exp_bias can turn into a
71     very large number (e.g., given the exp_bias of 0x3fff and a 64
72     bit long, the equation (long)(1 - exp_bias) evaluates to
73     4294950914) instead of -16382).  */
74  int exp_bias;
75  /* Exponent value which indicates NaN.  This is the actual value stored in
76     the float, not adjusted by the exp_bias.  This usually consists of all
77     one bits.  */
78  unsigned int exp_nan;
79
80  unsigned int man_start;
81  unsigned int man_len;
82
83  /* Is the integer bit explicit or implicit?  */
84  enum floatformat_intbit intbit;
85
86  /* Internal name for debugging. */
87  const char *name;
88
89  /* Validator method.  */
90  int (*is_valid) (const struct floatformat *fmt, const void *from);
91
92  /* Is the format actually the sum of two smaller floating point
93     formats (IBM long double, as described in
94     gcc/config/rs6000/darwin-ldouble-format)?  If so, this is the
95     smaller format in question, and the fields sign_start through
96     intbit describe the first half.  If not, this is NULL.  */
97  const struct floatformat *split_half;
98};
99
100/* floatformats for IEEE single and double, big and little endian.  */
101
102extern const struct floatformat floatformat_ieee_half_big;
103extern const struct floatformat floatformat_ieee_half_little;
104extern const struct floatformat floatformat_ieee_single_big;
105extern const struct floatformat floatformat_ieee_single_little;
106extern const struct floatformat floatformat_ieee_double_big;
107extern const struct floatformat floatformat_ieee_double_little;
108
109/* floatformat for ARM IEEE double, little endian bytes and big endian words */
110
111extern const struct floatformat floatformat_ieee_double_littlebyte_bigword;
112
113/* floatformats for VAX.  */
114
115extern const struct floatformat floatformat_vax_f;
116extern const struct floatformat floatformat_vax_d;
117extern const struct floatformat floatformat_vax_g;
118
119/* floatformats for various extendeds.  */
120
121extern const struct floatformat floatformat_i387_ext;
122extern const struct floatformat floatformat_m68881_ext;
123extern const struct floatformat floatformat_i960_ext;
124extern const struct floatformat floatformat_m88110_ext;
125extern const struct floatformat floatformat_m88110_harris_ext;
126extern const struct floatformat floatformat_arm_ext_big;
127extern const struct floatformat floatformat_arm_ext_littlebyte_bigword;
128/* IA-64 Floating Point register spilt into memory.  */
129extern const struct floatformat floatformat_ia64_spill_big;
130extern const struct floatformat floatformat_ia64_spill_little;
131extern const struct floatformat floatformat_ia64_quad_big;
132extern const struct floatformat floatformat_ia64_quad_little;
133/* IBM long double (double+double).  */
134extern const struct floatformat floatformat_ibm_long_double_big;
135extern const struct floatformat floatformat_ibm_long_double_little;
136
137/* Convert from FMT to a double.
138   FROM is the address of the extended float.
139   Store the double in *TO.  */
140
141extern void
142floatformat_to_double (const struct floatformat *, const void *, double *);
143
144/* The converse: convert the double *FROM to FMT
145   and store where TO points.  */
146
147extern void
148floatformat_from_double (const struct floatformat *, const double *, void *);
149
150/* Return non-zero iff the data at FROM is a valid number in format FMT.  */
151
152extern int
153floatformat_is_valid (const struct floatformat *fmt, const void *from);
154
155#ifdef __cplusplus
156}
157#endif
158
159#endif  /* defined (FLOATFORMAT_H) */
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