Set default value for signal from input

Question

Is there any way to set default value of signal from input? Like this:

entity NORMAL_CONTROL is
    Port (INPUT : in  STD_LOGIC_VECTOR (8 downto 0));
end NORMAL_CONTROL;

architecture Behavioral of NORMAL_CONTROL is

    signal S : STD_LOGIC_VECTOR (8 downto 0) := INPUT;

begin

end Behavioral;

This code does not have error but it apparently doesn't set default value for S!