ALUSrc
ALUSrc is a control signal used in the CPU datapath to determine the second operand fed to the arithmetic logic unit (ALU). In many MIPS-style single-cycle designs, ALUSrc is implemented as a one-bit multiplexer that selects between the second register operand and a sign-extended immediate value derived from the instruction.
When ALUSrc is 0, the ALU’s second input comes from ReadData2 (the second register file output). This
In the standard MIPS datapath, ALUSrc works in concert with other control signals that determine the ALU
In summary, ALUSrc is a key, single-bit control that selects between a register-based operand and a sign-extended