//  doubleprint.iml  (c) 2000 Kari Laitinen

//  This program prints the text "I am IBM" as
//  "II  aamm  IIBBMM" on the screen.

//  The text is printed in two parts. The main program calls
//  a subroutine named "doubleprint_text" which in turn calls
//  a subroutine named "output_register_a_twice".
//  A subroutine that has been called by some program can
//  thus itself call another subroutine.

//  NOTE: The purpose of this program is not to make jokes
//  about the company "International Business Machines (IBM)"
//  or its products. Rather, with this program it is intended
//  to say that our Imaginary Computer is very simple and
//  powerless when compared to the large real computers that
//  are manufactured by IBM corporation.

beginning_of_main_program:
      set_memory_pointer            first_part_of_text
      call_subroutine               doubleprint_text
      set_memory_pointer            second_part_of_text
      call_subroutine               doubleprint_text
      stop_processing

first_part_of_text:    STRING        "I am "
second_part_of_text:   STRING        "IBM"

doubleprint_text:
      load_register_a_from_memory
      jump_if_register_a_zero       end_of_doubleprint_text
      call_subroutine               output_register_a_twice
      increment_memory_pointer
      jump_to_address               doubleprint_text
end_of_doubleprint_text:
      return_to_calling_program


output_register_a_twice:
      output_byte_from_register_a
      output_byte_from_register_a
      return_to_calling_program