entity DomaciZadatak2 is
    Port ( iSEL : in  STD_LOGIC;
           iSW : in  STD_LOGIC_VECTOR (7 downto 0);
           oLED : out  STD_LOGIC_VECTOR (7 downto 0));
end DomaciZadatak2;

architecture Behavioral of DomaciZadatak2 is

begin
    process (iSEL,iSW) begin
        case(iSEL) is
            when '0' =>
                oLED <= not(iSW);
            when '1' =>
                oLED(3 downto 0) <= iSW(7 downto 4) - iSW(3 downto 0);
                if( iSW(7 downto 4) > iSW(3 downto 0)) then
                    oLED(4) <= '0';
                else
                    oLED(4) <= '1';
                end if;
--              dis dont work
--              not(iSW + "1") and
--              oLED(7 downto 5) <= ((not(iSW) + "1")and iSW);


                case ((not(iSW) + "1") and iSW) is
                    when "10000000"
                    => oLED(7 downto 5) <= "111";
                    when "01000000"
                    => oLED(7 downto 5) <= "110";
                    when "00100000"
                    => oLED(7 downto 5) <= "101";
                    when "00010000"
                    => oLED(7 downto 5) <= "100";
                    when "00001000"
                    => oLED(7 downto 5) <= "011";
                    when "00000100"
                    => oLED(7 downto 5) <= "010";
                    when "00000010"
                    => oLED(7 downto 5) <= "001";
                    when "00000001"
                    => oLED(7 downto 5) <= "000";
                    when others => oLED <= (others => '0');
                end case;


            when others => oLED <= (others => '1');
        end case;

    end process;

end Behavioral;