[SOLVED] why is there a delay at my MUX?

	process(clk,rst)
	begin 
		if(rst = '1') then
			pr_mux <= mux0;
		elsif(clk'event and clk = '1') then
			pr_mux <= nx_mux;
		end if;
	end process;
	
	process(pr_mux, addr6240_delay)
	begin
		case pr_mux is
			when mux0 =>  -- 0 ~ 2079 
				buffer_data <= doutb_interleaver_0;
				if(addr6240_delay = "0100000011111") then  --2079 
					nx_mux <= mux1;
				end if;
			when mux1 =>  --2080 ~ 4159
				buffer_data <= doutb_interleaver_1;
				if(addr6240_delay = "1000000111111") then
					nx_mux <= mux2;
				end if;
			when mux2 => -- 4160 ~ 6239
				buffer_data <= doutb_interleaver_2;
				if(addr6240_delay = "1100001011111") then
					nx_mux <= mux0;
				end if;
		end case;
	end process;

	process(addr6240_delay)
	begin
		if(addr6240_delay <= "0100000011111" and addr6240_delay >= "0000000000000") then
			buffer_data <= doutb_interleaver_0;
		elsif(addr6240_delay <= "1000000111111" and addr6240_delay >= "0100000100000") then
			buffer_data <= doutb_interleaver_1;
		elsif(addr6240_delay <= "1100001011111" and addr6240_delay >= "1000001000000") then
			buffer_data <= doutb_interleaver_2;
		end if;
	end process;