1. Equality Detector Lecture L6.1 Section 6.1

2. Equality Detector XNOR X Y Z Z = !(X $ Y) X Y Z 0 0 1 0 1 0 1 0 0 1 1 1

3. 4-Bit Equality Comparator A = [A3..A0]; B = [B3..B0]; C = [C3..C0];

4. Sets A = [A3..A0]; B = [B3..B0]; C = [C3..C0]; A represents [A3, A2, A1, A0] B represents [B3, B2, B1, B0] C represents [C3, C2, C1, C0]

5. MODULE eqcomp1 TITLE '4-BIT EQUALITY DETECTOR, R. Haskell, 9/21/02‘ DECLARATIONS " INPUT PINS " A3..A0 PIN 6, 7, 11, 5; A = [A3..A0]; B3..B0 PIN 72, 71, 66, 70; B = [B3..B0]; " OUTPUT PINS " A_EQ_B PIN 36; C3..C0 NODE; C = [C3..C0]; ABEL Program

6. EQUATIONS C = !(A $ B); A_EQ_B = C0 & C1 & C2 & C3; test_vectors ([A, B] -> [A_EQ_B]) [0, 0] -> [1]; [2, 5] -> [0]; [10, 12] -> [0]; [7, 8] -> [0]; [4, 2] -> [0]; [6, 6] -> [1]; [15, 15] -> [1]; END ABEL Program (cont.)

7. C = !(A $ B) C0 = !(A0 $ B0) C1 = !(A1 $ B1) C2 = !(A2 $ B2) C3 = !(A3 $ B3) EQUATIONS C = !(A $ B); A_EQ_B = C0 & C1 & C2 & C3;

11. Question Expand the following ABEL equation for F: A = [A2..A0]; B = [B2..B0]; F = [F2..F0]; F = !A & B;