as: Dot

 
 5.4 The Special Dot Symbol
 ==========================
 
 The special symbol '.' refers to the current address that 'as' is
 assembling into.  Thus, the expression 'melvin: .long .' defines
 'melvin' to contain its own address.  Assigning a value to '.' is
 treated the same as a '.org' directive.  Thus, the expression '.=.+4' is
 the same as saying '.space 4'.