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