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//////////////////////////////////////////////////////////////////////

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////  dbg_crc8_d1 crc1.v                                          ////

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////                                                              ////

////  This file is part of the SoC/OpenRISC Development Interface ////

////  http://www.opencores.org/cores/DebugInterface/              ////

////                                                              ////

////                                                              ////

////  Author(s):                                                  ////

////       Igor Mohor                                             ////

////       igorm@opencores.org                                    ////

////                                                              ////

////                                                              ////

////  All additional information is avaliable in the README.txt   ////

////  file.                                                       ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2000,2001 Authors                              ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser General   ////

//// Public License as published by the Free Software Foundation; ////

//// either version 2.1 of the License, or (at your option) any   ////

//// later version.                                               ////

////                                                              ////

//// This source is distributed in the hope that it will be       ////

//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////

//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////

//// PURPOSE.  See the GNU Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

// Revision 1.1.1.1  2001/10/06 10:19:09  igorm

// no message

//

// Revision 1.2  2001/09/20 10:11:25  mohor

// Working version. Few bugs fixed, comments added.

//

// Revision 1.1.1.1  2001/09/13 13:49:19  mohor

// Initial official release.

//

// Revision 1.3  2001/06/01 22:22:36  mohor

// This is a backup. It is not a fully working version. Not for use, yet.

//

// Revision 1.2  2001/05/18 13:10:00  mohor

// Headers changed. All additional information is now avaliable in the README.txt file.

//

// Revision 1.1.1.1  2001/05/18 06:35:03  mohor

// Initial release

//

//

///////////////////////////////////////////////////////////////////////

// File:  CRC8_D1.v

// Date:  Fri Apr 27 20:56:55 2001

//

// Copyright (C) 1999 Easics NV.

// This source file may be used and distributed without restriction

// provided that this copyright statement is not removed from the file

// and that any derivative work contains the original copyright notice

// and the associated disclaimer.

//

// THIS SOURCE FILE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS

// OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

// WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

//

// Purpose: Verilog module containing a synthesizable CRC function

//   * polynomial: (0 1 2 8)

//   * data width: 1

//

// Info: jand@easics.be (Jan Decaluwe)

//       http://www.easics.com

///////////////////////////////////////////////////////////////////////

`include "dbg_timescale.v"

`include "dbg_defines.v"

module dbg_crc8_d1 (Data, EnableCrc, Reset, SyncResetCrc, CrcOut, Clk);

parameter Tp = 1;

input Data;

input EnableCrc;

input Reset;

input SyncResetCrc;

input Clk;

output [7:0] CrcOut;

reg    [7:0] CrcOut;

always @ (posedge Clk or posedge Reset)

begin

  if(Reset)

    CrcOut[7:0] <= #Tp 0;

  else

  if(SyncResetCrc)

    CrcOut[7:0] <= #Tp 0;

  else

  if(EnableCrc)

    CrcOut[7:0] <= #Tp nextCRC8_D1(Data, CrcOut);

end

// polynomial: (0 1 2 8)

// data width: 1

function [7:0] nextCRC8_D1;

  input Data;

  input [7:0] Crc;

  reg [0:0] D;

  reg [7:0] C;

  reg [7:0] NewCRC;

  begin

    D[0] = Data;

    C = Crc;

    NewCRC[0] = D[0] ^ C[7];

    NewCRC[1] = D[0] ^ C[0] ^ C[7];

    NewCRC[2] = D[0] ^ C[1] ^ C[7];

    NewCRC[3] = C[2];

    NewCRC[4] = C[3];

    NewCRC[5] = C[4];

    NewCRC[6] = C[5];

    NewCRC[7] = C[6];

    nextCRC8_D1 = NewCRC;

  end

endfunction

endmodule