There are several variations on this plan. First of all, if there is no operand, as is the case with instructions A2S, S2A, HLT, STS, LDS, SHL, SHR, NOP and RET, the operand fetch stage is skipped and the computer immediately moves on to executing the instruction. Thus, these no-operand instructions are faster.

Second, the LDI instruction merely copies the lower 12-bits of the IR directly into the TMP register without going to memory. LDI stands for LoaD Immediate. The adjective immediate is used when the data is immediately available in the instruction, and does have to be explicitly fetch later. LDI is faster than LOD because the second memory read (operand fetch step) can be skipped.