Quadrature with Reset Line

quad.v

module quad(clk, rst, quadA, quadB, count);
input clk, rst, quadA, quadB;
output [7:0] count;

reg [2:0] quadA_delayed;
reg [2:0] quadB_delayed;


always @(posedge clk) quadA_delayed <= {quadA_delayed[1:0], quadA};
always @(posedge clk) quadB_delayed <= {quadB_delayed[1:0], quadB};

wire count_enable = quadA_delayed[1] ^ quadA_delayed[2] ^ quadB_delayed[1] ^ quadB_delayed[2];
wire count_direction = quadA_delayed[1] ^ quadB_delayed[2];

reg [7:0] count;
always @(posedge clk) begin
  if(rst) begin
    count <= 0;
  end
  else if(~rst & count_enable)
  begin
    if(count_direction) count<=count+1; else count<=count-1;
  end
end


endmodule