`define WIDTH 8
module linear_feedback_shift_register_updown (clk, reset, enable, up_down, count, overflow);
input clk;
input reset;
input enable; 
input up_down;

output [`WIDTH-1 : 0] count;
output overflow;

reg [`WIDTH-1 : 0] count;

assign overflow = (up_down) ? (count == {{`WIDTH-1{1'b0}}, 1'b1}) : 
                              (count == {1'b1, {`WIDTH-1{1'b0}}}) ;

always @(posedge clk)
if (reset) 
  count <= {`WIDTH{1'b0}};
else if (enable) begin
  if (up_down) begin
    count <= {~(^(count & `WIDTH'b01100011)),count[`WIDTH-1:1]};
  end else begin
    count <= {count[`WIDTH-2:0],~(^(count &  `WIDTH'b10110001))};
  end
end

endmodule