1
/*****************************************************************************
2
** Name: src/common/extended.c
3
** Purpose: IEEE Extended<->Double routines to save floats to file
4
** Maintainer: Ryan Norton
7
** RCS-ID: $Id: extended.c 67254 2011-03-20 00:14:35Z DS $
8
*****************************************************************************/
11
#if defined(_WIN32_WCE)
12
/* eVC cause warnings in its own headers: stdlib.h and winnt.h */
13
#pragma warning (disable:4115)
14
#pragma warning (disable:4214)
24
#if defined(_WIN32_WCE)
25
#pragma warning (default:4115)
26
#pragma warning (default:4214)
33
/* Copyright (C) 1989-1991 Ken Turkowski. <turk@computer.org>
35
* All rights reserved.
37
* Warranty Information
38
* Even though I have reviewed this software, I make no warranty
39
* or representation, either express or implied, with respect to this
40
* software, its quality, accuracy, merchantability, or fitness for a
41
* particular purpose. As a result, this software is provided "as is,"
42
* and you, its user, are assuming the entire risk as to its quality
45
* This code may be used and freely distributed as long as it includes
46
* this copyright notice and the above warranty information.
48
* Machine-independent I/O routines for IEEE floating-point numbers.
50
* NaN's and infinities are converted to HUGE_VAL or HUGE, which
51
* happens to be infinity on IEEE machines. Unfortunately, it is
52
* impossible to preserve NaN's in a machine-independent way.
53
* Infinities are, however, preserved on IEEE machines.
55
* These routines have been tested on the following machines:
56
* Apple Macintosh, MPW 3.1 C compiler
57
* Apple Macintosh, THINK C compiler
58
* Silicon Graphics IRIS, MIPS compiler
60
* Digital Equipment VAX
61
* Sequent Balance (Multiprocesor 386)
65
* Implemented by Malcolm Slaney and Ken Turkowski.
67
* Malcolm Slaney contributions during 1988-1990 include big- and little-
68
* endian file I/O, conversion to and from Motorola's extended 80-bit
69
* floating-point format, and conversions to and from IEEE single-
70
* precision floating-point format.
72
* In 1991, Ken Turkowski implemented the conversions to and from
73
* IEEE double-precision format, added more precision to the extended
74
* conversions, and accommodated conversions involving +/- infinity,
75
* NaN's, and denormalized numbers.
79
# define HUGE_VAL HUGE
83
/****************************************************************
84
* The following two routines make up for deficiencies in many
85
* compilers to convert properly between unsigned integers and
86
* floating-point. Some compilers which have this bug are the
87
* THINK_C compiler for the Macintosh and the C compiler for the
88
* Silicon Graphics MIPS-based Iris.
89
****************************************************************/
91
#ifdef applec /* The Apple C compiler works */
92
# define FloatToUnsigned(f) ((wxUint32)(f))
93
# define UnsignedToFloat(u) ((wxFloat64)(u))
95
# define FloatToUnsigned(f) ((wxUint32)(((wxInt32)((f) - 2147483648.0)) + 2147483647L) + 1)
96
# define UnsignedToFloat(u) (((wxFloat64)((wxInt32)((u) - 2147483647L - 1))) + 2147483648.0)
101
/****************************************************************
102
* Extended precision IEEE floating-point conversion routines.
103
* Extended is an 80-bit number as defined by Motorola,
104
* with a sign bit, 15 bits of exponent (offset 16383?),
105
* and a 64-bit mantissa, with no hidden bit.
106
****************************************************************/
108
WXDLLIMPEXP_BASE wxFloat64 wxConvertFromIeeeExtended(const wxInt8 *bytes)
112
wxUint32 hiMant, loMant;
114
expon = ((bytes[0] & 0x7F) << 8) | (bytes[1] & 0xFF);
115
hiMant = ((wxUint32)(bytes[2] & 0xFF) << 24)
116
| ((wxUint32)(bytes[3] & 0xFF) << 16)
117
| ((wxUint32)(bytes[4] & 0xFF) << 8)
118
| ((wxUint32)(bytes[5] & 0xFF));
119
loMant = ((wxUint32)(bytes[6] & 0xFF) << 24)
120
| ((wxUint32)(bytes[7] & 0xFF) << 16)
121
| ((wxUint32)(bytes[8] & 0xFF) << 8)
122
| ((wxUint32)(bytes[9] & 0xFF));
124
if (expon == 0 && hiMant == 0 && loMant == 0) {
128
if (expon == 0x7FFF) { /* Infinity or NaN */
133
f = ldexp(UnsignedToFloat(hiMant), expon-=31);
134
f += ldexp(UnsignedToFloat(loMant), expon-=32);
145
/****************************************************************/
148
WXDLLIMPEXP_BASE void wxConvertToIeeeExtended(wxFloat64 num, wxInt8 *bytes)
152
wxFloat64 fMant, fsMant;
153
wxUint32 hiMant, loMant;
163
expon = 0; hiMant = 0; loMant = 0;
166
fMant = frexp(num, &expon);
167
if ((expon > 16384) || !(fMant < 1)) { /* Infinity or NaN */
168
expon = sign|0x7FFF; hiMant = 0; loMant = 0; /* infinity */
172
if (expon < 0) { /* denormalized */
173
fMant = ldexp(fMant, expon);
177
fMant = ldexp(fMant, 32); fsMant = floor(fMant); hiMant = FloatToUnsigned(fsMant);
178
fMant = ldexp(fMant - fsMant, 32); fsMant = floor(fMant); loMant = FloatToUnsigned(fsMant);
182
bytes[0] = expon >> 8;
184
bytes[2] = hiMant >> 24;
185
bytes[3] = hiMant >> 16;
186
bytes[4] = hiMant >> 8;
188
bytes[6] = loMant >> 24;
189
bytes[7] = loMant >> 16;
190
bytes[8] = loMant >> 8;
194
#if WXWIN_COMPATIBILITY_2_8
195
WXDLLIMPEXP_BASE wxFloat64 ConvertFromIeeeExtended(const wxInt8 *bytes)
197
return wxConvertFromIeeeExtended(bytes);
200
WXDLLIMPEXP_BASE void ConvertToIeeeExtended(wxFloat64 num, wxInt8 *bytes)
202
wxConvertToIeeeExtended(num, bytes);
204
#endif // WXWIN_COMPATIBILITY_2_8
206
#endif /* wxUSE_APPLE_IEEE */