The Register Lab

Step through real x86-64 instructions and watch values move between registers, flags, the stack and memory.

program.asm
    Shortcut: press → to step.

    Predict it

    x86-64 core · simulated

    Registers 64-bit general purpose

    ALU

    Idle. Math shows its work here.

    Flags

    Bits of RAXlow 16

    Stack grows down ↓

    Memory .data