EE 360N - Problem Set 1 Clarifications

1. How should we go about answering Question 8?

   For Question 8, think about the different addressing modes used by different classes of instructions (i.e. Data Movement, Operate, Control). Operate instructions use different addressing modes than Data Movement instructions. For example, the ADD instruction uses the register mode. One or both of its operands are in registers.

2. Can we use any memory locations in the answer of Question 12?

   No. You should only use R1 and R2, if you need to store any values.

3. Problem 14 asks us to calculate the number of cycles taken by each instruction and each program. How can we solve this?

   You cannot solve this problem until we cover the LC-3b state machine in class. Therefore, you are not responsible for this problem. It will be a problem in the second problem set.

4. Answer Problem 15 assuming that the mentioned LC-3b instruction is a user instruction. In other words, it is in a user program. Hint: Think about the memory map of the LC-3b, the memory space available for user programs. Second Hint: What else do you need to think about when answering Part b?

5. Second option of Problem 9 is not clear. Answer this option assuming that it reads:
   "In a memory location associated with the subroutine. A different memory location is used for each different subroutine."