More Control Signals
00 Second ALU input from register rt
ALUSelB 01 Second ALU input is constant 4
10 Second ALU input is sign extended 16 lsb of IR
11 Second ALU input is sign extended 16 lsb of IR shifted
ALUOp 01 ALU performs subtraction
10 ALU operation comes from function code of instruction
00 Output of ALU(PC+4) is sent to PC for writing
PCSource 01 Contents of ALUOut (branch target)are sent to PC for writing
10 Jump target adddress is sent to PC for writing