diff --git a/npc/core/build.sbt b/npc/core/build.sbt
index 792a764..16f31f3 100644
--- a/npc/core/build.sbt
+++ b/npc/core/build.sbt
@@ -6,10 +6,11 @@ val chiselVersion = "5.1.0"
 
 lazy val root = (project in file("."))
   .settings(
-    name := "ChiselLearning",
+    name := "flow",
     libraryDependencies ++= Seq(
       "org.chipsalliance" %% "chisel" % chiselVersion,
-      "edu.berkeley.cs" %% "chiseltest" % "5.0.2" % "test"
+      "edu.berkeley.cs" %% "chiseltest" % "5.0.2" % "test",
+      "com.chuusai" %% "shapeless" % "2.3.3"
     ),
     scalacOptions ++= Seq(
       "-language:reflectiveCalls",
diff --git a/npc/core/src/main/scala/RegisterFile.scala b/npc/core/src/main/scala/RegisterFile.scala
index fbf8a94..a6c5a62 100644
--- a/npc/core/src/main/scala/RegisterFile.scala
+++ b/npc/core/src/main/scala/RegisterFile.scala
@@ -1,25 +1,73 @@
-package npc.util
+package flowpc.components
 
 import chisel3._
+import chisel3.util.log2Ceil
+import chisel3.util.UIntToOH
+import chisel3.util.MuxLookup
 
-class RegisterFile(readPorts: Int) extends Module {
-  require(readPorts >= 0)
-  val io = IO(new Bundle {
-    val writeEnable = Input(Bool())
-    val writeAddr = Input(UInt(5.W))
-    val writeData = Input(UInt(32.W))
-    val readAddr = Input(Vec(readPorts, UInt(5.W)))
-    val readData = Output(Vec(readPorts, UInt(32.W)))
-  })
+class RegControl extends Bundle {
+  val writeEnable = Input(Bool()) 
 
-  val regFile = RegInit(VecInit(Seq.fill(32)(0.U(32.W))))
-  for (i <- 1 until 32) {
-    regFile(i) := regFile(i)
+  object WriteSelect extends ChiselEnum {
+    val rAluOut, rMemOut = Value
+  }
+  val writeSelect = Input(WriteSelect())
+}
+
+class RegFileData[T <: Data](size:Int, tpe: T, numReadPorts: Int, numWritePorts: Int) extends Bundle {
+  val write = new Bundle {
+    val addr = Input(UInt(size.W))
+    val data = Vec(numWritePorts, Input(tpe))
+  }
+  val read = Vec(numReadPorts, new Bundle {
+    val rs = Input(UInt(size.W))
+    val src = Output(tpe)
+  })
+}
+
+class RegFileInterface[T <: Data](size: Int, tpe: T, numReadPorts: Int, numWritePorts: Int) extends Bundle {
+  val control = new RegControl
+  val data = new RegFileData(size, tpe, numReadPorts, numWritePorts)
+}
+
+class RegisterFileCore[T <: Data](size: Int, tpe: T, numReadPorts: Int) extends Module {
+  require(numReadPorts >= 0)
+  val writePort = IO(new Bundle {
+    val enable = Input(Bool())
+    val addr = Input(UInt(log2Ceil(size).W))
+    val data = Input(tpe)
+  })
+  val readPorts = IO(Vec(numReadPorts, new Bundle {
+    val addr = Input(UInt(log2Ceil(size).W))
+    val data = Output(tpe)
+  }))
+
+  val regFile = RegInit(VecInit(Seq.fill(size)(0.U(tpe.getWidth.W))))
+  val writeAddrOH = UIntToOH(writePort.addr)
+  for ((reg, i) <- regFile.zipWithIndex.tail) {
+    reg := Mux(writeAddrOH(i) && writePort.enable, writePort.data, reg)
   }
-  regFile(io.writeAddr) := Mux(io.writeEnable, io.writeData, regFile(io.writeAddr))
   regFile(0) := 0.U
 
-  for (i <- 0 until readPorts) {
-    io.readData(i) := regFile(io.readAddr(i))
+  for (readPort <- readPorts) {
+    readPort.data := regFile(readPort.addr)
+  }
+}
+
+object RegisterFile {
+  def apply[T <: Data](size: Int, tpe: T, numReadPorts: Int, numWritePorts: Int): RegFileInterface[T] = {
+    val core = Module(new RegisterFileCore(size, tpe, numReadPorts))
+    val _out = Wire(new RegFileInterface(size, tpe, numReadPorts, numWritePorts))
+    val clock = core.clock
+    for (i <- 0 until numReadPorts) {
+      core.readPorts(i).addr := _out.data.read(i).rs
+      _out.data.read(i).src := core.readPorts(i).data
+    }
+    core.writePort.addr := _out.data.write.addr
+    core.writePort.data := MuxLookup(_out.control.writeSelect, 0.U)(
+      _out.control.WriteSelect.all.map(x => (x -> _out.data.write.data(x.asUInt).asUInt))
+    )
+    core.writePort.enable := _out.control.writeEnable
+    _out
   }
 }
diff --git a/npc/core/src/test/scala/RegisterFile.scala b/npc/core/src/test/scala/RegisterFile.scala
new file mode 100644
index 0000000..87be171
--- /dev/null
+++ b/npc/core/src/test/scala/RegisterFile.scala
@@ -0,0 +1,63 @@
+package flowpc
+
+import chisel3._
+import chiseltest._
+import org.scalatest.freespec.AnyFreeSpec
+import chiseltest.simulator.WriteVcdAnnotation
+
+import flowpc.components._
+class RegisterFileSpec extends AnyFreeSpec with ChiselScalatestTester {
+  "RegisterFileCore" - {
+    "register 0 is always 0" in {
+      test(new RegisterFileCore(32, UInt(32.W), 2)) { c =>
+          c.readPorts(0).addr.poke(0)
+          c.readPorts(1).addr.poke(0)
+          c.writePort.enable.poke(true)
+          c.writePort.addr.poke(0)
+          c.writePort.data.poke(0x1234)
+
+          c.readPorts(0).data.expect(0)
+          c.readPorts(1).data.expect(0)
+          c.clock.step(2)
+          c.readPorts(0).data.expect(0)
+          c.readPorts(1).data.expect(0)
+        }
+    }
+    "register other than 0 can be written" in {
+      test(new RegisterFileCore(32, UInt(32.W), 2)) { c =>
+          import scala.util.Random
+          val r = new Random()
+          for (i <- 1 until 32) {
+            val v = r.nextLong() & 0xFFFFFFFFL
+            c.readPorts(0).addr.poke(i)
+            c.writePort.enable.poke(true)
+            c.writePort.addr.poke(i)
+            c.writePort.data.poke(v)
+
+            c.clock.step(1)
+            c.readPorts(0).data.expect(v)
+          }
+        }
+    }
+  }
+  "RegisterInterface" - {
+    "worked" in {
+      class Top extends Module {
+        val io = IO(new RegFileInterface(32, UInt(32.W), 2, 2))
+        val rf = RegisterFile(32, UInt(32.W), 2, 2)
+        io :<>= rf
+      }
+      test(new Top).withAnnotations(Seq(WriteVcdAnnotation)) { c =>
+        import c.io.control.WriteSelect._
+        val writePort = rAluOut.litValue.toInt
+        c.io.control.writeEnable.poke(true)
+        c.io.control.writeSelect.poke(rAluOut)
+        c.io.data.write.addr.poke(5)
+        c.io.data.write.data(writePort).poke(0xcdef)
+        c.io.data.read(0).rs.poke(5)
+        c.clock.step(1)
+        c.io.data.read(0).src.expect(0xcdef)
+      }
+    }
+  }
+}