1. The following sequence of control point assignments implements the ADD instruction in the CSC-1. Circle those lines that implement the four stages of the instruction cycle and label each circle:

                1. MAR-MUX=01
                2. MAR-LD=1
                3. MAR-LD=0;  MA=1;  WR=0;  MBR-MUX=10
                4. MBR-LD=1
                5. MBR-LD=0;  MA=0;  PC-INCR=1;  IR-LD=1
                6. IR-LD=0;  PC-LD=1
                7. PC-INCR=0;  PC-LD=0
                8. MAR-MUX=00
                9. MAR-LD=1
               10. MAR-LD=0;  MA=1;  WR=0;  MBR-MUX=10
               11. MBR-LD=1
               12. MBR-LD=0;  MA=0
               13. TMP-LD=1
               14. TMP-LD=0;  F=101;  SH=00
               15. A-MUX=00
               16. A-LD=1
               17. A-LD=0

2. Which stage is included in some architectures but not an "official" stage in the CSC-1's instruction cycle?

3. Why is it a good idea to turn off a control wire after it has been turned on? For instance, A-LD=0 explicitly follows A-LD=1 in step 17.

4. Which steps of the above sequence of control point assignments would be done for every single instruction in the CSC-1?

5. List several instructions that do not have a real execute stage in the CSC-1.

6. Why would it be a good idea to make the control point sequence for an instruction as short as possible?

7. Which lines in the original 17-line control point sequence were combined to get the 13-line sequence shown at the end of Section 8.4?