.s 
print 1000
stop  1001
S     50 
I     51
M11   52
.a 0
.c
  lda #0
  sta I
  sta S
:while
  lda I
  add M11
  jpz exit
  lda S
  add I
  sta S
  lda I
  add #1
  sta I
  jmp while
:exit
  lda S
  jsr print
  jsr stop
.a 50
.b 0 0 245
.e 

   