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);

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

    end process;

end Behavioral;