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[/] [wf3d/] [trunk/] [rtl/] [core/] [fm_3d_fcnv.v] - Rev 7
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//======================================================================= // Project Monophony // Wire-Frame 3D Graphics Accelerator IP Core // // File: // fm_3d_fcnv.v // // Abstract: // 3D float conversion IEEE single floating point number to // 22-bits floating point number // // Author: // Kenji Ishimaru (info.wf3d@gmail.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 module fm_3d_fcnv ( i_f32, o_f22 ); //////////////////////////// // I/O definition //////////////////////////// input [31:0] i_f32; output [21:0] o_f22; //////////////////////////// // assign //////////////////////////// assign o_f22 = f_f32_to_f22(i_f32); //////////////////////////// // function //////////////////////////// function [21:0] f_f32_to_f22; input [31:0] f32; reg s; reg [7:0] e8; reg [8:0] e8d; // width sign bit reg [4:0] e5; reg [23:0] m23; reg [14:0] m15; reg carry; reg zf; begin s = f32[31]; e8 = f32[30:23]; zf = (e8 == 8'h00); m23 = f32[22:0]; {carry,m15} = m23[22:8] + m23[7]; e8d = e8 - 112 + carry; // -127+15 + carry if (zf|e8d[8]) begin e5 = 5'h0; end else begin e5 = e8d[4:0]; end f_f32_to_f22 = {s,e5,!(zf|e8d[8]),m15}; end endfunction endmodule
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