Figure 3—The pipelined datapath has an execution unit, a result multiplexer, and an address/PC unit. Operands from the register file or immediate field are selected and latched into the A and B operand registers. Then the function units, including ADDSUB, operate upon A and B, and one of the results is driven onto RESULT15:0 and written back into the register file. Meanwhile, the address/PC unit increments the PC to help fetch the next instruction.