Section 7.3
Review Questions

Control Points

  1. Define control point.
  1. In the figure below, circle or indicate some control wires and then, using a different color or some other manner, point out a few data wires.
  1. What is the name of the combinational circuit that acts as a traffic cop, directing several different roads that converge to the same place? In this analogy, roads are wires and the "same place" refers to the registers.
  1. Which of the 8 combinations of the F control wires correspond to actual instructions in the CSC-1's instruction set?
  1. Why can't the CSC-1 handle circular and arithmetic shifts, since it already handles right and left logical shifts?
  1. Which component generates the C, N, Z and V wires?
  1. Which two control wires control main memory?
  1. Who or what decides when and which control wires get turned on and off?
  1. Suppose that we wanted to be able to funnel the PC's output into the A register. What would this mean for A's multiplexor?
  1. For each of the F codes below, write what function the ALU computes.
            F2  F1  F0
          ------------------------------
            1   1   1     ______________
          
            0   1   0     ______________
          
            0   0   1     ______________
          
            0   1   1     ______________
          
            1   0   1     ______________
          
            0   0   0     ______________
          
            1   1   0     ______________
          
            1   0   0     ______________