#[global]
Instance Op_div : BinOp div :=
  {| TBOp := quots ; TBOpInj := div_quots |}.

Lemma quots_spec (x y : Z) : ((x = -4611686018427387904 /\ y = -1 /\ quots x y = -4611686018427387904) \/ ((x <> -4611686018427387904 \/ y <> -1) /\ quots x y = Z.quot x y))%Z.