| /////////////////////////////////////////////////////////////////////////// |
| // |
| // 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. |
| // |
| /////////////////////////////////////////////////////////////////////////// |
| |
| |
| |
| |
| //--------------------------------------------------------------------------- |
| // |
| // toFloat |
| // |
| // A program to generate the lookup table for half-to-float |
| // conversion needed by class half. |
| // The program loops over all 65536 possible half numbers, |
| // converts each of them to a float, and prints the result. |
| // |
| //--------------------------------------------------------------------------- |
| |
| |
| #include <iostream> |
| #include <iomanip> |
| |
| using namespace std; |
| |
| //--------------------------------------------------- |
| // Interpret an unsigned short bit pattern as a half, |
| // and convert that half to the corresponding float's |
| // bit pattern. |
| //--------------------------------------------------- |
| |
| unsigned int |
| halfToFloat (unsigned short y) |
| { |
| |
| int s = (y >> 15) & 0x00000001; |
| int e = (y >> 10) & 0x0000001f; |
| int m = y & 0x000003ff; |
| |
| if (e == 0) |
| { |
| if (m == 0) |
| { |
| // |
| // Plus or minus zero |
| // |
| |
| return s << 31; |
| } |
| else |
| { |
| // |
| // Denormalized number -- renormalize it |
| // |
| |
| while (!(m & 0x00000400)) |
| { |
| m <<= 1; |
| e -= 1; |
| } |
| |
| e += 1; |
| m &= ~0x00000400; |
| } |
| } |
| else if (e == 31) |
| { |
| if (m == 0) |
| { |
| // |
| // Positive or negative infinity |
| // |
| |
| return (s << 31) | 0x7f800000; |
| } |
| else |
| { |
| // |
| // Nan -- preserve sign and significand bits |
| // |
| |
| return (s << 31) | 0x7f800000 | (m << 13); |
| } |
| } |
| |
| // |
| // Normalized number |
| // |
| |
| e = e + (127 - 15); |
| m = m << 13; |
| |
| // |
| // Assemble s, e and m. |
| // |
| |
| return (s << 31) | (e << 23) | m; |
| } |
| |
| |
| //--------------------------------------------- |
| // Main - prints the half-to-float lookup table |
| //--------------------------------------------- |
| |
| int |
| main () |
| { |
| cout.precision (9); |
| cout.setf (ios_base::hex, ios_base::basefield); |
| |
| cout << "//\n" |
| "// This is an automatically generated file.\n" |
| "// Do not edit.\n" |
| "//\n\n"; |
| |
| cout << "{\n "; |
| |
| const int iMax = (1 << 16); |
| |
| for (int i = 0; i < iMax; i++) |
| { |
| cout << "{0x" << setfill ('0') << setw (8) << halfToFloat (i) << "}, "; |
| |
| if (i % 4 == 3) |
| { |
| cout << "\n"; |
| |
| if (i < iMax - 1) |
| cout << " "; |
| } |
| } |
| |
| cout << "};\n"; |
| return 0; |
| } |