.lcomm  var1 4

.global _start
_start:

   # load the address of "var1" into register %eax
   movl $var1,%eax  # eax = &var1
   movb $0xcd,2(%eax) # *((char *)eax + 2) = 0xcd
   
   movl $0, %ebx
   movl $1, %eax
   int  $0x80