A student writes:

     On page 127 it is explaining how Base+offset works.
     I can't seem to understand
     how the figure 5.8 is working. I think the instruction
     might be wrong in the
     figure. the opcode in the figure is LDI R3 R3 x001d.
     When i think it should be
     LDR R1 R2 x001d. If the figure is correct then i have
     no clue what is going on with Base+offset.

You are absolutely correct. I thought it had been corrected on the McGraw-Hill errata page, but I see it has not. Under the instruction, it says as you noticed LDR R1 R2 x001d, but in the IR it has gibberish. Groan. Thank you for pointing it out.

The IR should contain: 0110 001 010 011101

Yale Patt