11/13/2006
Those of you who are studying the old exams in EE 306 should be aware of important changes from the LC-2 to the LC-3. Some of the instructions are encoded differently for the two ISAs, and some of those differences are subtle. Rather than list all the differences, let me simply suggest that while you are welcome to look at the problems on the old exams, the solutions that are provided may not be correct in terms of the LC-3. One example is the LD instruction, where bits[8:0] of the instruction are used differently in the LC-2 and LC-3 to compute the address of the load. There are many others. Good luck on the second midterm on Wednesday. Yale Patt