;-------------------------------------
;-- testVID.asm
;--  Sends string to display. While-loop version.
;-------------------------------------

.ORIG x0200

    lea r1, MSG           ;-- char_ptr <== &MSG  (1st char)
    ldr r0, r1, 0         ;-- char     <== *char_ptr

while_nonNUL:             ;-- while( char != NUL )
    brz done              ;-- begin_while_non_NUL       

poll:                     ;--   do
    ldi r2, DSR           ;--      status <== DSR
    brzp poll             ;--   until( status == READY )
                          
    sti r0, DDR           ;--   DDR <== char (print char)

    add r1, r1, 1         ;--   char_ptr++  (next char)
    ldr r0, r1, 0         ;--   char <== *char_ptr

    br  while_nonNUL      ;-- end_while_non_NUL

done:
    ld  r4, STOP_CLOCK    ;--         R4  <== STOP_CLOCK
    sti r4, MCR           ;-- MCR <== R4      (shutdown LC3)

  MSG:            .STRINGZ "\nAre You Happy To See ME?\n"
  DSR:            .FILL xFE04  ;-- display status register
  DDR:            .FILL xFE06  ;-- display data register
  STOP_CLOCK:     .FILL x8000  ;-- MCR[15] == 1 (stop clock)
  MCR:            .FILL xFFFE  ;-- machine control register

.END