a.scala

object a {

  def sub(in: Long): Int = {
    val masked: Long = in & 0x0101010101010101L
    (0 until 7).foldLeft(masked) {(v, i) => (v & 0xff) | (v >> 7)}.toInt
  }

  def sub2(inp: Long): Int = {
    val m1 = inp & 0x0101010101010101L
    val m2 = (m1 & 0x0001000100010001L) | (m1 >> 7)
    val m3 = (m2 & 0x0000000300000003L) | (m2 >> 14)
    val m4 = (m3 & 0x000000000000000fL) | (m3 >> 28)
    m4.toInt
  }

  def main(args: Array[String]): Unit = {
    val in = 0xab000000000000ffL
    println(Integer.toString(sub(in), 16))
    println(Integer.toString(sub2(in), 16))
  }

}

// $ scalac a.scala && scala a
// 81
// 81