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library ieee; use ieee.std_logic_1164.all; entity dff07 is port (q : out std_logic; d : std_logic; clk : std_logic); end dff07; architecture behav of dff07 is begin process (clk) is variable a, b : std_logic; begin if rising_edge (clk) then a := d; b := a; q <= b; end if; end process; end behav;