advent-of-code/2020/day2/vhdl/top.vhd

library ieee;
use ieee.std_logic_1164.all,
    ieee.numeric_std.all;

entity top is
	generic (
		COUNTER_WIDTH : positive;
		STEP : natural range 1 to 2
	);
	port (
		clk : in std_logic;
		reset : in std_logic;
		char  : in character;
		is_record : in std_logic;
		num_verified : out unsigned(COUNTER_WIDTH-1 downto 0)
	);
end entity;

architecture behaviour of top is
	signal is_data : std_logic;
	signal num1, num2 : natural range 0 to 99;
	signal letter : character;

	signal prev_is_record : std_logic;
	signal record_ended : std_logic;

	signal verified : std_logic;
begin
	record_ended <= prev_is_record and not is_record;

	parser_inst: entity work.parser
		port map (
			clk   => clk,
			reset => reset,
			is_record => is_record,
			is_data   => is_data,
			char   => char,

			num1   => num1,
			num2   => num2,
			letter => letter
		);

	generate_verifier: if step = 1 generate
		verifier_inst: entity work.verifier(step1)
			port map (
				clk => clk,
				reset => reset or record_ended,
				is_data => is_data,
				num1   => num1,
				num2   => num2,
				letter => letter,
				char   => char,
				verified => verified
			);
	elsif step = 2 generate
		verifier_inst: entity work.verifier(step2)
			port map (
				clk => clk,
				reset => reset or record_ended,
				is_data => is_data,
				num1   => num1,
				num2   => num2,
				letter => letter,
				char   => char,
				verified => verified
			);
	else generate
		assert false report "Bad value for ""step""" severity failure;
	end generate;

	process(clk)
	begin
		if rising_edge(clk) then
			prev_is_record <= is_record;
			if reset then
				prev_is_record <= '0';
				num_verified <= (others => '0');
			elsif record_ended and verified then
				num_verified <= num_verified + 1;
			end if;
		end if;
	end process;
end architecture;