Introduction To X86 Disassembly May 2026

The "Instruction Pointer," the finger that points to the exact line of code currently being executed. 2. The First Discovery: MOV and ADD

Suddenly, you hit a line that says CMP EAX, 20 followed by JNE 0x401050 . The machine is checking if your total is 20. Introduction to x86 disassembly

This is your first "artifact." You realize the machine is the number 5 into the EAX slot. The next line says ADD EAX, 10 . Now you know the machine is calculating 3. The Locked Door (Control Flow) The "Instruction Pointer," the finger that points to

As you dig deeper, you find a "Stack"—a literal pile of data. Programs use the to remember where they were before they started a side-task. The program PUSHes its current location onto the stack. The machine is checking if your total is 20

The "Stack Pointer," a bookmark showing where you are in a pile of papers.