anchor.diff:     ;
   
   line
  -   : (assemblerdirective | instruction)? comment?
  +   :lbl? (assemblerdirective | instruction)? comment?
      ;
   
   instruction
  -   : lbl? prefix? opcode expressionlist?
  +   : prefix? opcode? expressionlist?
      ;
   
   lbl
  -   : label ':'
  +   : label ':'?
      ;
   
   prefix
  
positive.code:    ;
  
  org
     : ORG string
     ;
  
  title
  
negative.code:    | equ
     | db
     | dw
     | cseg
     | dseg
     | title
     | include
     ;
  
  cseg
     : CSEG
     ;
  
  dseg
     : DSEG
     ;
  
  dw
     : DW expressionlist
     ;
  