//A 4-bit adder with carry in and carry out
class alu32 extends Module {
  val io = IO(new Bundle {
    val in1  = Input(UInt(32.W))
    val in2  = Input(UInt(32.W))
    val aluop= Input(UInt(2.W))
    val out  = Output(UInt(65.W))
  })
  //ALU for adder32
  val alu0 = Module(new Adder32())
  alu0.io.in1 := io.in1
  alu0.io.in2 := io.in2
  alu0.io.out(31,0) := io.out
  //ALU for sub32
  val alu1 = Module(new sub32())
  alu1.io.in1 := io.in1
  alu1.io.in2 := io.in2
  alu1.io.out(31,0) := io.out
  //ALU for mul32
  val alu2 = Module(new mul32())
  alu2.io.in1 := io.in1
  alu2.io.in2 := io.in2
  alu2.io.in2 := io.out
  //ALU for div32
  val alu3 = Module(new div32())
  alu3.io.in1 := io.in1
  alu3.io.in2 := io.in2
  alu3.io.in2(31,0) := io.out
  switch(io.aluop)
  {
    is(0.U) {io.out := alu0.io.out}
    is(1.U) {io.out := alu1.io.out}
    is(2.U) {io.out := alu2.io.out}
    is(3.U) {io.out := alu3.io.out}
  }
}