.lcomm  var1 4

.global _start
_start:

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