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[/] [wf3d/] [trunk/] [bin/] [f22.c] - Rev 3
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//======================================================================= // Project Monophony // Wire-Frame 3D Graphics Accelerator IP Core // // File: // f22.c // // Abstract: // 22-bit floating point number utility // // Author: // Kenji Ishimaru (kenji.ishimaru@prtissimo.com) // //====================================================================== // // Copyright (c) 2015, Kenji Ishimaru // 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. // // 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 HOLDER 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. // // Revision History #include <stdio.h> union { unsigned int ui; float f; } uif; float cnv_f22_to_f32(unsigned int a) { // extract sign unsigned int tmp_s = (a >> 21) & 1; // extract exp unsigned int tmp_e = (a >> 16) & 0x1f; unsigned int tmp_oe = (a >> 16) & 0x1f; // extract fraction(with integer bit) unsigned int tmp_m = a & 0xffff; if ((tmp_oe != 0)||(tmp_m != 0)) { tmp_e -= 15; tmp_e += 127; } // denormal if ((tmp_oe == 0)&&(tmp_m != 0)) { while (((tmp_m >> 15)&1) != 1) { tmp_m = tmp_m << 1; tmp_e--; } } tmp_m = (tmp_m << 1) & 0xfff; // remove integer bit unsigned int t = (tmp_s << 31) | (tmp_e << 23) | (tmp_m << 7); uif.ui = t; return uif.f; } int main() { unsigned int x; while (1) { printf("f22 = "); scanf("%x", &x); printf("float value = %f\n",cnv_f22_to_f32(x)); } }
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