A digital system has three registers AR, BR and PR. Three flip-flops provide the control variables for the system: S is a flip-flop that is set by an external Start signal to start the operation, and F and R are two flip-flops used in sequencing the micro-operations when the system is in operation. A fourth flip-flop D is set by the system when the operation is completed. The operation of the digital system is described by the following register transfer statements: S: PR+0, S + 0, F + 1, D+0 F:F+0, if BR = 0 then D+1 else R+1 R: PR + PR+ AR, BR + BR 1, R+0, F+1 (a) What is the function of the above digital system? [10] (b) Draw a block diagram of the hardware implementation of the above system. Include a start input to set flip-flop S and Done output from flip-flop D. [10]