func divRem(q, r: var openArray[Word]; a, b: openArray[Word]) {....raises: [],
    gcsafe, tags: [], forbids: [].}

func divRem[qLen, rLen, aLen, bLen: static int](q: var array[qLen, Word];
    r: var array[rLen, Word]; a: array[aLen, Word]; b: array[bLen, Word]) {.
    ...raises: [], gcsafe.}

func shortDiv(a: var Limbs; k: Word): Word {....raises: [], gcsafe.}