Altera code to read from address 0x0400

The following AHDL TDF file will cause the signal r400 to go high when on a read from address 0x0400, and low otherwise.

SUBDESIGN r400_eqn
(
    R_W             :  INPUT; 
    E               :  INPUT;
    LSTRBn          :  INPUT;
    A[15..0]        :  INPUT;  % Demultiplexed address bits % 
    
    r400            :  OUTPUT; % High when reading from address 0x0400 %
)


BEGIN

    if ((A[15..0] == H"0400") & (R_W == VCC) & (E == VCC)) THEN
        r400 = VCC;
    ELSE
        r400 = GND;
    END IF;

END;