Subversion Repositories pcie_vera_tb

// ===========================================================================

// File    : scramble8.vri

// Author  : cwinward

// Date    : Mon Dec 3 11:03:46 MST 2007

// Project : TI PHY design

//

// Copyright (c) notice

// This code adheres to the GNU public license

//

// ===========================================================================

//

// $Id: scramble8.vri,v 1.1.1.1 2007-12-05 18:37:07 cmagleby Exp $

//

// ===========================================================================

//

// $Log: not supported by cvs2svn $

//

// ===========================================================================

// Function : This file scrambles the rx lines and descrambles the tx lines.

//

// ===========================================================================

// ===========================================================================

#include 

task scramble8(bit [7:0] data_in, bit skp_detect, bit com_detect, bit sram_bypass, bit [15:0] lfsr_old, var bit [7:0] scramble_data, var bit [15:0] lfsr) {

    if((sram_bypass == 1'b1) | (com_detect == 1'b1)) {

       scramble_data = data_in;

     }

     else {

       scramble_data[0] = lfsr_old[15] ^ data_in[0];

       scramble_data[1] = lfsr_old[14] ^ data_in[1];

       scramble_data[2] = lfsr_old[13] ^ data_in[2];

       scramble_data[3] = lfsr_old[12] ^ data_in[3];

       scramble_data[4] = lfsr_old[11] ^ data_in[4];

       scramble_data[5] = lfsr_old[10] ^ data_in[5];

       scramble_data[6] = lfsr_old[9]  ^ data_in[6];

       scramble_data[7] = lfsr_old[8]  ^ data_in[7];

     }

    if(com_detect == 1'b1) {

      lfsr = 16'hFFFF;

    }

    else if(skp_detect == 1'b0) {

      lfsr[0]  =  lfsr_old[8];

      lfsr[1]  =  lfsr_old[9];

      lfsr[2]  =  lfsr_old[10];

      lfsr[3]  =  lfsr_old[8] ^ lfsr_old[11];

      lfsr[4]  =  lfsr_old[8] ^ lfsr_old[9] ^ lfsr_old[12];

      lfsr[5]  =  lfsr_old[8] ^ lfsr_old[9] ^ lfsr_old[10] ^ lfsr_old[13];

      lfsr[6]  =  lfsr_old[9] ^ lfsr_old[10] ^ lfsr_old[11] ^ lfsr_old[14];

      lfsr[7]  =  lfsr_old[10] ^ lfsr_old[11] ^ lfsr_old[12] ^ lfsr_old[15];

      lfsr[8]  =  lfsr_old[0] ^ lfsr_old[11] ^ lfsr_old[12] ^ lfsr_old[13];

      lfsr[9]  =  lfsr_old[1] ^ lfsr_old[12] ^ lfsr_old[13] ^ lfsr_old[14];

      lfsr[10] =  lfsr_old[2] ^ lfsr_old[13] ^ lfsr_old[14] ^ lfsr_old[15];

      lfsr[11] =  lfsr_old[3] ^ lfsr_old[14] ^ lfsr_old[15];

      lfsr[12] =  lfsr_old[4] ^ lfsr_old[15];

      lfsr[13] =  lfsr_old[5];

      lfsr[14] =  lfsr_old[6];

      lfsr[15] =  lfsr_old[7];

    }

    else {

      lfsr = lfsr_old;

    }

}