Initial Chisel core implementation

src/main/scala/csr/PrivilegeControl.scala

@@ -0,0 +1,21 @@
+import chisel3._
+
+class PrivilegeControl(p: CoreParams = CoreParams()) extends Module {
+  val io = IO(new Bundle {
+    val trap = Input(Bool())
+    val mret = Input(Bool())
+    val sret = Input(Bool())
+    val privilege = Output(UInt(2.W))
+  })
+
+  val mode = RegInit(3.U(2.W))
+  when(io.trap) {
+    mode := 3.U
+  }.elsewhen(io.mret) {
+    mode := 0.U
+  }.elsewhen(io.sret) {
+    mode := 0.U
+  }
+  io.privilege := mode
+}
+