init repo

lab3/src/test/scala/riscv/PipelineRegisterTest.scala

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+// 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 riscv
+
+import chisel3._
+import chiseltest._
+import org.scalatest.flatspec.AnyFlatSpec
+import riscv.core.PipelineRegister
+
+import scala.math.pow
+import scala.util.Random
+
+
+class PipelineRegisterTest extends AnyFlatSpec with ChiselScalatestTester {
+  behavior of "Pipeline Register"
+  it should "be able to stall and flush" in {
+    val rand = new Random
+    val default_value = rand.nextInt(pow(2, Parameters.DataBits).toInt).asUInt(Parameters.DataWidth)
+    test(new PipelineRegister(Parameters.DataBits, default_value)).withAnnotations(TestAnnotations.annos) { c =>
+      var pre = default_value
+      for (_ <- 1 to 1000) {
+        val cur = rand.nextInt(pow(2, Parameters.DataBits).toInt).asUInt(Parameters.DataWidth)
+        c.io.in.poke(cur)
+        rand.nextInt(3) match {
+          case 0 =>
+            c.io.stall.poke(false.B)
+            c.io.flush.poke(false.B)
+            c.clock.step()
+            c.io.out.expect(cur)
+            pre = cur
+          case 1 =>
+            c.io.stall.poke(true.B)
+            c.io.flush.poke(false.B)
+            c.clock.step()
+            c.io.out.expect(pre)
+          case 2 =>
+            c.io.stall.poke(false.B)
+            c.io.flush.poke(true.B)
+            c.clock.step()
+            c.io.out.expect(default_value)
+            pre = default_value
+        }
+      }
+    }
+  }
+}