addr_size = 4
int32_size = 4
.data

message: .asciz "Hello, World!\n"

.text
.global _start
_start:
  pushl  $5
  pushl  $7
  pushl  $message
  call   sub1
  addl   $12,%esp
  
  movl   $0,%ebx
  movl   $1,%eax
  int    $0x80
  
sub1:
  oldBP = 0
  retAddr = oldBP + 4
  pMess = retAddr + addr_size
  start = pMess + addr_size
  start_size = int32_size
  len = start + start_size
  
  pushl  %ebp
  movl   %esp,%ebp # snapshot of SP as frame pointer
  # need to computer pMess + start, and put the sum
  # into ecx
  movl   pMess(%ebp),%ecx # ecx becomes a pointer to the message
  addl   start(%ebp),%ecx # ecx becomes the sum of message address and start
  
  movl   len(%ebp),%edx
  
  movl   $1,%ebx
  
  movl   $4,%eax
  
  int    $0x80
  
  popl   %ebp
  ret