$2.(10$ points$)$ Consider the basic single$-$cycle MIPS datapath that implements a subset of the MIPS instruction set $($add$,$ subtract, and, or$,$ Iw$,$ sw$,$ beq, jump$).$ We would like to modify this datapath to implement the swapm instruction:

Instruction: swapm rs$,$ rt

Interpretation: $\backslash (\backslash$quad R$[$r t$]=$M$[$R$[$r s$]]\backslash )$

$\backslash [$

M$[$R$[$r s$]]=$R$[$r t$]$

$\backslash ]$

Please refer to the single cycle diagram below:

a$)$ Which existing blocks will we use? Do we need to add new functional units or modify existing ones? Do we need extra control signals? Explain how data is flowing in the datapath.

b$)$ Specify the value of each control signal $($RegDst$,$ ALUSrc, ALUOp, MemRead, MemWrite, MemToReg, RegWrite, Branch$)$ as well as the value of any additional signal if needed.