1 ///////////////////////////////////////////////////////////////////////////
2 //
3 // Copyright (c) 2006, Industrial Light & Magic, a division of Lucas
4 // Digital Ltd. LLC
5 //
6 // All rights reserved.
7 //
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9 // modification, are permitted provided that the following conditions are
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14 // copyright notice, this list of conditions and the following disclaimer
15 // in the documentation and/or other materials provided with the
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32 //
33 ///////////////////////////////////////////////////////////////////////////
34
35 //---------------------------------------------------------------------------
36 //
37 // b44ExpLogTable
38 //
39 // A program to generate lookup tables for
40 //
41 // y = exp (x / 8)
42 //
43 // and
44 // x = 8 * log (x);
45 //
46 // where x and y are 16-bit floating-point numbers
47 //
48 // The tables are used by class B44Compressor.
49 //
50 //---------------------------------------------------------------------------
51
52 #include <half.h>
53 #include <math.h>
54 #include <iostream>
55 #include <iomanip>
56
57 using namespace std;
58
59 //---------------------------------------------
60 // Main - prints the half-to-float lookup table
61 //---------------------------------------------
62
63 int
main()64 main ()
65 {
66 #ifndef HAVE_IOS_BASE
67 cout.setf (ios::hex, ios::basefield);
68 #else
69 cout.setf (ios_base::hex, ios_base::basefield);
70 #endif
71
72 cout << "//\n"
73 "// This is an automatically generated file.\n"
74 "// Do not edit.\n"
75 "//\n\n";
76
77 const int iMax = (1 << 16);
78
79 cout << "const unsigned short expTable[] =\n"
80 "{\n"
81 " ";
82
83 for (int i = 0; i < iMax; i++)
84 {
85 half h;
86 h.setBits (i);
87
88 if (!h.isFinite())
89 h = 0;
90 else if (h >= 8 * log (HALF_MAX))
91 h = HALF_MAX;
92 else
93 h = exp (h / 8);
94
95 cout << "0x" << setfill ('0') << setw (4) << h.bits() << ", ";
96
97 if (i % 8 == 7)
98 {
99 cout << "\n";
100
101 if (i < iMax - 1)
102 cout << " ";
103 }
104 }
105
106 cout << "};\n\n";
107
108 cout << "const unsigned short logTable[] =\n"
109 "{\n"
110 " ";
111
112 for (int i = 0; i < iMax; i++)
113 {
114 half h;
115 h.setBits (i);
116
117 if (!h.isFinite() || h < 0)
118 h = 0;
119 else
120 h = 8 * log (h);
121
122 cout << "0x" << setfill ('0') << setw (4) << h.bits() << ", ";
123
124 if (i % 8 == 7)
125 {
126 cout << "\n";
127
128 if (i < iMax - 1)
129 cout << " ";
130 }
131 }
132
133 cout << "};\n";
134
135 return 0;
136 }
137