The mic008.txt data file. This Mic-1 program illustrates a conditional jump and a write to memory. More importantly, it shows how to compute the difference ac = e - d. 6 microinstructions: A C M O A M M E U N L S B A R W N C B A ADDR X D U H R R D R C 0 0 0 1 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 1 0 1 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 1 0 1 0 0 0 0 0 1 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Mac-1 instructions 0 data items for main memory Register values: PC AC SP IR TIR 0 +1 -1 AMASK SMASK A B C D E F 0 0 69 0 0 0 1 -1 4095 255 42 0 0 8 7 6 The MAL form of the above microinstructions follows: 0: ac := inv(d); (inverse is 1's complement, boolean not) 1: ac := ac + e; 2: ac := ac + 1; if n then goto 4; (n means N Flag of 1 set by ALU output) 3: ac := ac + f; 4: mar := a; mbr := ac; wr; 5: wr; Note that we have computed the desired difference as follows: ac = e - d = e + inv(d) + 1 since in 2's complement arithmetic subtracting something is done by adding the 1's complement (boolean not) and then adding 1. The simulator loads registers a, d, e, and f as shown above. The value in a is the location to write the answer to. Since e - d = 7 - 8 = -1, the conditional jump should be done, thus skipping line 3. End of the mic008.txt data file.