Chapter 4, Problem 4.1.1E

Control signals of the image:

• ALUMux is the control signal that is used to control the Mux at the ALU input.
• RegMux is the control signal that is used to control the Mux at the data input to the register file.

Operation process that take place:

• From the given instruction, AND is the ALU operation that is to be performed.
• BSrc is the Mux that is present at the southern part which is used to determine whether the immediate operand or register is being passed to the ALU.
• OpSel is the command that is send to the ALU.
• MemWrite will be false since no memory write operation is performed.
• RegWrite will be true because data are written back to the register Rd.
• RegDst is the destination register and it will hold Rd.
• PCSrc will remain same since no jump operation is performed. Its value will be “PC+4”.

Value of the control signals are:

• RegWrite = 0
• MemRead = 0
• AluMux = 1
• MemWrite= 1
• ALUop = ADD
• Reg,ux = x
• Branch = 0

Process:

• 0(Reg) will select the output of the register file and 1(IMM) will select the immediate instruction word as use it as a second input to the ALU.
• 0 (ALU) will select the output of the ALU that is provided, and 1 (Mem) will select the output of memory.
• “X” indicates the don’t care value.