Referencing the contents of a memory location. (x86 addressing modes)

Question

I have a memory location that contains a character that I want to compare with another character (and it\'s not at the top of the stack so I can\'t just pop it)

Answer 1

Here is a quick cheatsheet, retrieved from this site. It shows the various methods available for addressing main memory in x86 assembly:

+------------------------+----------------------------+-----------------------------+
| Mode                   | Intel                      | AT&T                        |
+------------------------+----------------------------+-----------------------------+
| Absolute               | MOV EAX, [0100]            | movl           0x0100, %eax |
| Register               | MOV EAX, [ESI]             | movl           (%esi), %eax |
| Reg + Off              | MOV EAX, [EBP-8]           | movl         -8(%ebp), %eax |
| Reg*Scale + Off        | MOV EAX, [EBX*4 + 0100]    | movl   0x100(,%ebx,4), %eax |
| Base + Reg*Scale + Off | MOV EAX, [EDX + EBX*4 + 8] | movl 0x8(%edx,%ebx,4), %eax |
+------------------------+----------------------------+-----------------------------+

---

In your specific case, if the item is located at an offset of 4 from the stack base EBP, you would use the Reg + Off notation:

MOV EAX, [ EBP - 4 ]

This would copy the item into register EAX.