code: function (m, n) {
        n %= 64
        if (n === 0) {
          return m
        } else if (n < 32) {
          return [(m[0] << n) | (m[1] >>> (32 - n)), m[1] << n]
        } else {
          return [m[1] << (n - 32), 0]
        }
      }
docs: Given a 64bit int (as an array of two 32bit ints) and an int representing a number of bit positions, returns the 64bit int (as an array of two 32bit ints) shifted left by that number of positions.