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115 lines
3.4 KiB
C++
115 lines
3.4 KiB
C++
///////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
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// Digital Ltd. LLC
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Industrial Light & Magic nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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///////////////////////////////////////////////////////////////////////////
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#include <iostream>
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#include <iomanip>
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using namespace std;
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//-----------------------------------------------------
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// Compute a lookup table for float-to-half conversion.
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//
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// When indexed with the combined sign and exponent of
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// a float, the table either returns the combined sign
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// and exponent of the corresponding half, or zero if
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// the corresponding half may not be normalized (zero,
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// denormalized, overflow).
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//-----------------------------------------------------
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void
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initELut (unsigned short eLut[])
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{
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for (int i = 0; i < 0x100; i++)
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{
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int e = (i & 0x0ff) - (127 - 15);
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if (e <= 0 || e >= 30)
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{
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//
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// Special case
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//
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eLut[i] = 0;
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eLut[i | 0x100] = 0;
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}
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else
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{
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//
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// Common case - normalized half, no exponent overflow possible
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//
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eLut[i] = (e << 10);
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eLut[i | 0x100] = ((e << 10) | 0x8000);
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}
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}
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}
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//------------------------------------------------------------
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// Main - prints the sign-and-exponent conversion lookup table
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//------------------------------------------------------------
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int
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main ()
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{
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const int tableSize = 1 << 9;
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unsigned short eLut[tableSize];
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initELut (eLut);
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cout << "//\n"
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"// This is an automatically generated file.\n"
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"// Do not edit.\n"
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"//\n\n";
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cout << "{\n ";
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for (int i = 0; i < tableSize; i++)
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{
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cout << setw (5) << eLut[i] << ", ";
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if (i % 8 == 7)
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{
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cout << "\n";
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if (i < tableSize - 1)
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cout << " ";
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}
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}
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cout << "};\n";
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return 0;
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}
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