The ALU control unit dictates the operation to be done by the ALU. It's truth table though describes only 7 operations, which are enlisted in the truth table below.
How the processor handles the rest of the instructions like XOR, NOR, Shifts etc.?
Should I extend the ALU Control Unit and include this instructions? Send the opcode through registers to the ALU stage and decode there also? Or something else?
None of this is explained in either MIPS diagrams or ALU Control Unit tables I looked at.