Question

4. List the values on the control signals for the following instructions. The MIPS architecture and instruction formats studied in class are shown below for reference. Your answer needs to be 1, 0, or X for each signal (a 0 or 1 will not be accepted as a substitute for X) MemtoReg MemWriteBranchALUSrc RegDst RegWrite sub r2, r5, r23 beq rl, r3, L2 sw rl, 36(r4) lw r3,100(r6) addi r2,rl4,-24 j L3 ontro Unit Write ranch PCSrc Op Funct LUSre Dst Write CLK WE3 Zero WE A1 RD1 A RD Instr Instruction ? ALUResult ReadData A RD Data A2 ?? WD3 File RD2 Register iteData Memory WD WriteReg Signimm Sign Extend

Answer 1

On the above table, sub is R -type instruction . in this operation performed using only registered and does not require memory operations. Therefore only registered and reg write is '1' and remaining all control signals are '0' rightarrow Beg instruction is branch equal. Therefore, only branch control is 'high' and some times this instruction depend upon Mem to Reg and Reg Dist. So Mem to reg and Reg Dist is assigned to 'X' rightarrow Sw instruction is used to store the result. Here register value is stirred in memory location and ALU used to calculate required memory location and adding offset to address field and remaining controls are ')' rightarrow LW instruction is use to load the content of memory location in to the register. Mem to Reg and Reg write is 'high' ALU used to calculate required memory location by adding offset to address