The operand fetch stage is next. In the CSC-1, the operand value retrieved from memory was placed in the TMP register since that was the only other input to the ALU. But in the CSC-2, any two registers can be inputs to the ALU, including the MBR. Hence, once the value is fetched (by copying IR to MAR, setting MA=1, WR=0 and selecting the MBR-mux to get the value out of memory), we can directly use that value from the MBR, adding it to A and storing the result back into A. The TMP register is therefore freed for other tasks. Some operations like multiplication and division require several extra registers.