what is the testbanch for this one ?

A computer system usually contains a several number of registers that hold data during various operations. Sometimes it is necessary to swap the contents of two registers. Typically, this is done by using a temporary location, which is usually a third register. For example, suppose that we want to swap the contents of registers R1 and R2. We can achieve this by first transferring the contents of R2 into the third register, say R3. Next, we transfer the contents of R1 into R2. Finally, we transfer the contents of R3 into R1. Figure I below shows the block diagram of the system. Write a Verilog program to describe the control circuit based on the given ASM in Figure 2. RI RI RI R2 ONE Clock Control circuit R2 Interconnection network R? Done R3 R3 Figure 1: A block diagram of parts of a computer system reset A 0 W HOT B 1 R2 R3 C RI our R2 R3, R1Done Figure 2: An ASM chart to implement the control circuit in Figure 1