code: function bnpLShiftTo(n, r) {
    var bs = n % this.DB;
    var cbs = this.DB - bs;
    var bm = (1 << cbs) - 1;
    var ds = Math.floor(n / this.DB), c = this.s << bs & this.DM, i;
    for (i = this.t - 1; i >= 0; --i) {
      r[i + ds + 1] = this[i] >> cbs | c;
      c = (this[i] & bm) << bs;
    }
    for (i = ds - 1; i >= 0; --i)
      r[i] = 0;
    r[ds] = c;
    r.t = this.t + ds + 1;
    r.s = this.s;
    r.clamp();
  }
docs: (protected) r = this << n