;  s21 with interrupt

.symbol
  cnt   100

.code 0
  jmp main

:isr    ; interrupt service routine
  ld r1 cnt
  add r1 r1 #1
  trap r1 #1
  st r1 cnt
  reti

:main
  mov r1 #isr
  st r1 1000     ; set int vec

  mov r1 #0
  st r1 cnt
:while
  jmp while

.data 200
.end
