interrupts off
  garbage <- free-pointer - limit
  tem2 <- free-pointer
  jump-greater-than
  md <- a0
  vma-start-write-early <- tem2
  free-pointer <- tem2 + 2
  md <- a1
  vma-start-write-cdr-early <- tem2
  interrupts on
  return tem2 + dtp-list


  open o1 <- index check dt fix,  24 bit
  ldb dt array-pointer
  call less than negative index
  dispatch-call o0 <- array-pointer

art-q:
  vma-start-read-early array-pointer
  tem1 <- dpb easy-bit index, 24 bit
  md - tem1, 24 bit
  tem2 <- array-pointer + index + 1
  jump greater index out of bounds
  vma-start-read-early <- tem2
  x
  return md


  open o2 <- data
  o1 <- index check dt fix,  24 bit
  ldb dt array-pointer
  call less than negative index
  dispatch-call o0 <- array-pointer

art-q:
  vma-start-read-early array-pointer
  tem1 <- dpb easy-bit index, 24 bit
  md - tem1, 24 bit
  tem2 <- array-pointer + index + 1
  jump greater index out of bounds
  md <- data
  vma-start-write-early <- tem2
  return data