.text
.global _start
_start:
    subl  $4,%esp # reserve four bytes on the stack for i
    movl  $5,(%esp) # initialize i to 5



    # call initInt0
    # push the address of i
    movl  %esp,%eax
    pushl %eax
    call  initInt0
    addl  $4,%esp

    movl  $1,%eax
    movl  $0,%ebx
    int   $0x80


initInt0:
  oldBp = 0
  retaddr = oldBp + 4
  ptr = retaddr + 4

  pushl  %ebp # to save old frame pointer
  movl   %esp,%ebp # take a snapshot of sp

  # need to first get the address (value of ptr)
  movl   ptr(%ebp),%eax
  # copy 0 to wherever ptr points to
  movl   $0,(%eax)

  movl   %ebp,%esp
  popl   %ebp
  ret