实验报告检查

lab4/朱梓涵24325356/bus/BusArbiter.scala

@@ -0,0 +1,40 @@
+// Copyright 2021 Howard Lau
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package bus
+
+import chisel3._
+import riscv.Parameters
+
+class BusArbiter extends Module {
+  val io = IO(new Bundle {
+    val bus_request = Input(Vec(Parameters.MasterDeviceCount, Bool()))
+    val bus_granted = Output(Vec(Parameters.MasterDeviceCount, Bool()))
+
+    val ctrl_stall_flag = Output(Bool())
+  })
+  val granted = Wire(UInt())
+  // Static Priority Arbitration
+  // Higher number = Higher priority
+  granted := 0.U
+  for (i <- 0 until Parameters.MasterDeviceCount) {
+    when(io.bus_request(i.U)) {
+      granted := i.U
+    }
+  }
+  for (i <- 0 until Parameters.MasterDeviceCount) {
+    io.bus_granted(i.U) := i.U === granted
+  }
+  io.ctrl_stall_flag := !io.bus_granted(0.U)
+}