Oh yeah, I forgot that SP points to an empty space. Okay, so I only need to decrement the value at SP first. I can't see how saving the value in R13 will help. After I set the A register to segment[index], I'll need to set M= value@R13. But if I try to load the value of R13, I'll end up overwriting the A register which I am using to point to segment[index]! An elaboration would be greatly appreciated. Thanks for your help.