.model tiny
.code
org 100h
 
main  proc
 
      mov    ah,9                       ; Display String Service
      mov    dx,offset hello_message    ; Offset of message (Segment DS is the right segment in .COM files)
      int    21h                        ; call DOS int 21h service to display message at ptr ds:dx
 
      retn                              ; returns to address 0000 off the stack 
                                        ; which points to bytes which make int 20h (exit program)
 
hello_message db 'Hello, World!$'
 
main  endp
end   main