//variables for HD calculation
  reg [N-1:0]         HD [0:2**N-1][0:2**N-1];
  reg [2**N-1:0]      i,j;
  reg [N-1:0]         summation;

   CALC_HD:
          begin
            for(i=0; i < 2**N;i=i+1)
              for(j=0; j < 2**N;j=j+1)
                begin
                 summation = sum(i^j); //function call
                 if( summation >= min_hd )
                    begin
                      HD[i][j] = 1;
                      //     $display("sum=%b,HD[%2d][%2d]=%2d\n",summation,i,j,HD[i][j]); //for debugging
                    end
                  else
                    HD[i][j] = 0;
                end // for (j=0; j < 2**N;j=j+1)
            next_state = ONE_TIME_SETUP;
             end


function [N-1:0] sum(input [N-1:0] input_vector);
    integer       k;
    reg [N-1:0]   temp;

    begin
      temp = 0;
      for(k=0; k < N; k=k+1)
        begin
          temp = temp + input_vector[k];
        end
      sum = temp;
    end

  endfunction // sum