module lcd_512(lcd_512_1_or_0,direction,clk,reset);
         output [511:0]lcd_512_1_or_0;
	 input [1:0] direction;
	 input clk,reset;

	 reg [8:0] head;
	 reg [8:0] next_head;
	 reg [4:0] counter;
         reg [4:0] next_counter;
         reg [3:0] lcd_512[0:511];
         reg [3:0] next_lcd_512[0:511];
	 reg [511:0]lcd_512_1_or_0;
         reg [511:0]next_lcd_512_1_or_0;

	 integer i;

	 always@(posedge clk or negedge reset)
	 begin
	     if(!reset)
		  begin
		      head<=9'd3;
				counter<=5'd3;
				lcd_512[0]<=4'b0001;
				lcd_512[1]<=4'b0010;
				lcd_512[2]<=4'b0011;

				for(i=3;i<512;i=i+1)
				begin
				    lcd_512[i]<=4'b0000;
				end

		      lcd_512_1_or_0<=512'd0;

		  end
		  else
		  begin
		      head<=next_head;
				counter<=next_counter;
				for(i=0;i<512;i=i+1)
				begin
				    lcd_512[i]<=next_lcd_512[i];
                                    lcd_512_1_or_0[i]<=next_lcd_512_1_or_0[i];
                                    $display("lcd_512[%d]=%d ",i,lcd_512[i]);
				end
                                $display("head=%b lcd_512_1_or_0=%b ",head,lcd_512_1_or_0);
                                for(i=0;i<512;i=i+1)
				begin
				     //lcd_512_1_or_0[i]<=1'b1;
				    $display("lcd_512_1_or_0[%d]=%d ",i,lcd_512_1_or_0[i]);

				end
		  end
	 end

	 always@(*)// head
	 begin
	     if(direction==2'b00)// direction is right
		  begin
		      if(head==9'd31||head==9'd63||head==9'd95||head==9'd127||head==9'd159||head==9'd191||head==9'd223||head==9'd255||head==9'd287||head==9'd319||head==9'd351||head==9'd383||head==9'd415||head==9'd447||head==9'd479||head==9'd511)
				begin// head to right boundary
				   next_head=head-31;// to left
			   end
				else// go to right
				begin
					next_head=head+1;
				end
		  end
		  else if(direction==2'b01)// direction is low
		  begin
			  if(head>=480&&head<=511)// head to bottom
			   begin
					next_head=head-480;// to top
				end
			  else
			  begin
					next_head=head+32;// go to bottom
			  end
		  end
		  else if(direction==2'b10)// direction is left
		  begin
		      if(head==9'd0||head==9'd32||head==9'd64||head==9'd96||head==9'd128||head==9'd160||head==9'd192||head==9'd224||head==9'd256||head==9'd288||head==9'd320||head==9'd352||head==9'd384||head==9'd416||head==9'd448||head==9'd480)
				begin// head to left boundary
					next_head=head+31;//to right
				end
				else
				begin
					next_head=head-1;// go to left
	         end
		  end
		  else if(direction==2'b11)// direction is up
		  begin
		      if(head>=0&&head<=31)// if head to top
				begin
				    next_head=head+480;// to bottom
				end
				else// don`t to top
				begin
					next_head=head-32;// go to top
	         end
		  end
		  else
		  begin
		      next_head=head;
		  end
	 end

	 always@(*)// counter
	 begin
	     next_counter=counter;
	 end

	 always@(*)// lcd_512
	 begin
	     next_lcd_512[head]=counter;
		  for(i=0;i<512;i=i+1)
		  begin
		      if(i!=head)
				begin
				    if(lcd_512[i]!=4'b0000)
					 begin
					     next_lcd_512[i]=lcd_512[i]-4'b0001;
					 end
					 else
					 begin
					     next_lcd_512[i]=4'b0000;
					 end
				end
				//$display("next_lcd_512[%d]=%d",i,next_lcd_512[i]);
		  end
	 end

	 always@(*)// lcd_512_1_or_0
	 begin
	     for(i=0;i<512;i=i+1)
		  begin
		      if(lcd_512[i]!=4'b0000)
				begin
				    //$display("%d ",i);
				    next_lcd_512_1_or_0[i]=1'b1;

				end
				else if(lcd_512[i]==4'b0000)
				begin
				    next_lcd_512_1_or_0[i]=1'b0;
				end
				else
				begin
				    next_lcd_512_1_or_0[i]=lcd_512_1_or_0[i] ;
				end
				$display("lcd_512_1_or_0[%d]=%d ",i,next_lcd_512_1_or_0[i]);
		  end
	 end

endmodule