-- Accumulateur

ENTITY accu IS
  PORT (
		i 	: in bit_vector(3 downto 0);
		ck 	: in bit;
		o	: out bit_vector(3 downto 0);
                vdd     : in bit;
                vss     : in bit

    );
END accu;


-- Architecture Declaration

ARCHITECTURE behaviour_data_flow OF accu IS


  SIGNAL q : REG_VECTOR(3 downto 0) REGISTER;	

BEGIN

-- accumulateur

registre : block (ck = '1' and not ck'stable) begin
	q <= guarded i;
	end block;

o <= q;

END;