3. [20pt] Assume an instruction: 0x00c6ba23 is located in memory at address: 0x0f1230b8. Answer the following questions when the instruction is executed based on the datapath and control shown in Figure 4.17.

a. What are the values of the ALU Control to the ALU unit?

b. What is the PC address after this instruction is executed?

c. What is the values (either 0 or 1) of the control signals to the three multiplexers?

d. What are the input values for the ALU?

0 Add 4 ALU Add result 1 Shift left 2 Instruction (31-26] RegDst Branch MemRead MemtoReg Control ALUOp MemWrite ALUST RegWrite PC Instruction [25-21) Read address Instruction (2016) Instruction [31-01 Instruction instruction [15-11) memory Read register 1 Read Read data 1 register 2 Write Read Zero ALU ALU Read Address data result register data 2 Write data Registers Write Data data memory Instruction [15-01 16 32 Sign- extend ALU control Instruction (5-0) FIGURE 4.17 The simple datapath with the control unit. The input to the control unit is the 6-bit opcode field from the instruction. The outputs of the control unit consist of three 1-bit signals that are used to control multiplexors (RegDst, ALUSrc, and Memto Reg), three signals for controlling reads and writes in the register file and data memory (RegWrite, MemRead, and Mem Write), a 1-bit signal used in determining whether to possibly branch (Branch), and a 2-bit control signal for the ALU (ALUO). An AND gate is used to combine the branch control signal and the Zero output from the ALU; the AND gate output controls the selection of the next PC. Notice that PCSrc is now a derived signal, rather than one coming directly from the control unit. Thus, we drop the signal name in subsequent figures