List the steps needed to execute the machine instruction Add LOCA,RO in terms of transfers between the components shown in Figure 1.2 and some simple control commands. Assume that the instruction itself is stored in the memory at location INSTR and that this address is initially in register PC. The first two steps might be expressed as Transfer the contents of register PC to register MAR. Issue a Read command to the memory, and then wait until it has transferred the requested word into register MDR. Remember to include the steps needed to update the contents of PC from INSTR to INSTR+1 so that the next instruction can be fetched.

LO1