I am working on a simple assembly program for a class, and am encountering an odd segmentation fault. It's a pretty simple program to convert bytes into kilobytes. However, within the function that does the conversion, I get a segmentation fault when I try to move the value 1024 into the ebx register. I've never had this kind of problem before when working with registers. Does someone know what could be causing this? I imagine it is something simple that I'm overlooking. Thank you!

asm_main:
    enter 0,0
    pusha

    mov eax, 0
    mov ebx, 0
    call read_int
    push eax
    call functionA

    popa
    mov
    leave
    ret
functionA:
    mov eax, [esp + 4]
    call print_int
    call print_nl
    mov ebx, 1024 ;segmentation fault occurs here
    div ebx
    call print_int
    ret

UPDATE: One interesting discovery is that if I delete the lines interacting with the stack, push eax and mov eax, [esp + 4], there is no longer a segmentation fault. However, I get a crazy result in eax after performing div ebx.