begin:

  lxi  h, $eaf3
  lxi  d, $d1d0
  lxi  b, 2340

copy:

  mov  a, m
  dcx  h
  ani  01111111b
  stax d
  inx  d
  dcx  b
  mov  a, c
  ora  b
  jnz  copy

check:

  lda  $ed02
  rlc
  rlc
  jc   key

  mvi  a, $d0
  sta  $f006
  mvi  a, $d1
  sta  $f006
  jmp  check

key:

  rlc
  jc   check

  mvi  a, $d0
  sta  $f006
  mvi  a, $e1
  sta  $f006

  jmp  check

