如何在装配体8086中使用基本指针来遍历堆栈？

Question

I have an assigment in which I have to insert two digit integers into the stack. Search a number in the stack and return in which position this number is, print all the numbers in the stack and delete a number from the stack.

Right now I'm trying to print all the numbers in the stack by going through the stack using the base pointer, but my code doesn't work.

mov di,offset bp   
mov ax, [di]     ;trying to move de value stored in di direction in stack to Ax
mov digito,ah
mov digito2,al

mov dl,digito
mov ah,02
int 21h

mov dl,digito2
mov ah,02
int 21h

mov ah,01
int 21h

So in this code I'm trying to print the two number digit by getting the bp into di (so later I can decrement it to go through all the stack), and the passing the number stored in that direction in Ax. I'm a newby in assembly so I don't know what I'm doing.

Thank you in advance for your time. (And sorry for my english)

Answer 1

Sorry for the delayed reply. First, bp doesn't really have an "offset", so you could remove that. Second, bp won't automatically point into the stack unless you have made it so ( mov bp, sp ).

You don't mention an OS, but int 21h identifies it as DOS... which is real mode, segmented memory model. mov ax, [di] defaults to mov ax, ds:[di] . If you've assembled this into a ".com" file, cs , ds , es , and ss are all the same. If you've assembled it into an ".exe" file, this is not so! You may want to write it as mov ax, ss:[di] to be sure. In contrast, mov ax, [bp] defaults to mov ax, ss:[bp] , so you may want to use bp instead of di here. I suspect that's how you're "supposed" to do it. If you've got a ".com" file, you can forget about this part (in 32-bit code you can forget about it too, but that doesn't apply to you).

Then... your attempt to print a number isn't really going to work properly. Look for "How do I print a number?" examples for more information on that - too much to get into here...

This is too hard an assignment for a beginner, IMO (but "the instructor is always right" :) ).