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

entity zad1 is
	port(
		A,B,C :in  std_logic_vector (7 downto 0);
		S 		:out std_logic_vector (7 downto 0)
	);
end entity;

architecture data_flow of zad1 is
		signal sum_A : integer range 0 to 18;
		signal sum_B : integer range 0 to 18;
		signal sum_C : integer range 0 to 18;
		signal A_int : integer range 0 to 99;
	   signal B_int : integer range 0 to 99;
		signal C_int : integer range 0 to 99;
		signal div   : std_logic_vector (2 downto 0);
begin
	process(A,B,C) is
		begin
		A_int <= to_integer(unsigned(A(7 downto 4)))*10 + to_integer(unsigned(A(3 downto 0)));
		B_int <= to_integer(unsigned(B(7 downto 4)))*10 + to_integer(unsigned(B(3 downto 0)));
		C_int <= to_integer(unsigned(C(7 downto 4)))*10 + to_integer(unsigned(C(3 downto 0)));

		sum_A <= to_integer(unsigned(A(7 downto 4))) + to_integer(unsigned(A(3 downto 0)));
		sum_B <= to_integer(unsigned(B(7 downto 4))) + to_integer(unsigned(B(3 downto 0)));
		sum_C <= to_integer(unsigned(C(7 downto 4))) + to_integer(unsigned(C(3 downto 0)));
--Sprawdzanie warunku podzielności przez 3
		S<="00000000";
			case sum_A is
				when 3 | 6 | 9 | 12 | 15 | 18 =>
					div(2) <= '1';
				when others =>
					div(2) <= '0';
			end case;

			case sum_B is
				when 3 | 6 | 9 | 12 | 15 | 18 =>
					div(1) <= '1';
				when others =>
					div(1) <= '0';
			end case;

			case sum_C is
				when 3 | 6 | 9 | 12 | 15 | 18 =>
					div(0) <= '1';
				when others =>
					div(0) <= '0';
			end case;
--Sprawdzanie która z liczb jest największa
			case div is
				when "000" =>
				S <= "00000000";
				when "001" =>
				S <= C;
				when "010" =>
				S <= B;
				when "011" =>
					if B_int>=C_int then
					S <= B;
					else
					S <= C;
					end if;
				when "100" =>
				S <= A;
				when "101" =>
					if A_int>=C_int then
					S <= A;
					else
					S <= C;
					end if;
				when "110" =>
					if A_int>=B_int then
					S <= A;
					else
					S <= B;
					end if;
				when "111" =>
					if A_int>=B_int then
						if C_int>=A_int then
							S <= C;
						elsif A_int>=C_int then
							S <= A;
						end if;

					elsif B_int>=A_int then
						if B_int>=C_int then
							S <= B;
						elsif C_int>=B_int then
							S <= C;
						end if;
					elsif C_int>=B_int then
						if C_int>=A_int then
							S <= C;
						elsif A_int>=C_int then
							S <= A;
						end if;
					else
						S <= C;
					end if;
			end case;
	end process;

end architecture;