А если так:
LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
ENTITY rstr IS
PORT( s : IN std_logic;
r : IN std_logic;
q : BUFFER std_logic;
qb : BUFFER std_logic );
END rstr;
ARCHITECTURE behav OF rstr IS
COMPONENT notand
PORT( a : IN std_logic;
b : IN std_logic;
c : OUT std_logic);
END COMPONENT;
BEGIN
u1: notand
PORT MAP ( s, qb, q);
u2: notand
PORT MAP (q, r, qb);
END behav;
CONFIGURATION con OF rstr IS
FOR behav
FOR u1, u2: notand
USE ENTITY work.notand (behavior);
END FOR;
END FOR;
END con;
