풀이

기존의 VecShiftRegister와 거의 다른 점이 없어서, 금방 풀었다.

Test Code

// See LICENSE.txt for license details.
package problems

import chisel3.iotesters.PeekPokeTester

class VecShiftRegisterParamTests(c: VecShiftRegisterParam) extends PeekPokeTester(c) {
  val reg = Array.fill(c.n){ 0 }
  for (t <- 0 until 16) {
    val in = rnd.nextInt(1 << c.w)
    poke(c.io.in, in)
    step(1)
    for (i <- c.n-1 to 1 by -1)
      reg(i) = reg(i-1)
    reg(0) = in
    expect(c.io.out, reg(c.n-1))
  }
}

• 랜덤한 입력을 쭉 넣는다.
• Array의 결과와 동일한지를 비교하는 TB이다.

오답 1

// See LICENSE.txt for license details.
package problems

import chisel3._

// Problem:
//
// Implement a parametrized simple shift register.
// 'n' is the number of elements in the shift register.
// 'w' is the width of one element.

class VecShiftRegisterParam(val n: Int, val w: Int) extends Module {
  val io = IO(new Bundle {
    val in  = Input(UInt(w.W))
    val out = Output(UInt(w.W))
  })

  // Implement below ----------
  val shift_reg = Reg(Vec(n, UInt(w.W)))
  for(i <- 1 until n){
    shift_reg(i) := shift_reg(i-1)
  }
  shift_reg(0) := io.in
  io.out := shift_reg(n)

}
// Implement above ----------

Exception이 제일 까다롭다..
어디서 에러가 떴는지 정확하게 짚어주지 않는다.
대충 이런 아주 긴 Excpetion이 나왔다.

info] Loading project definition from /home/user/Documents/chisel-tutorial/project
[info] Loading settings for project chisel-tutorial from build.sbt ...
[info] Set current project to chisel-tutorial (in build file:/home/user/Documents/chisel-tutorial/)
[info] sbt server started at local:///home/user/.sbt/1.0/server/f9829f7299b4fd9cac4a/sock
sbt:chisel-tutorial> test:runMain problems.Launcher VecShiftRegisterParam
[info] Compiling 1 Scala source to /home/user/Documents/chisel-tutorial/target/scala-2.12/classes ...
[warn] Multiple main classes detected.  Run 'show discoveredMainClasses' to see the list
[info] running problems.Launcher VecShiftRegisterParam
Starting tutorial VecShiftRegisterParam
[info] [0.001] Elaborating design...
chisel3.internal.ChiselException: Exception thrown when elaborating ChiselGeneratorAnnotation
	at chisel3.stage.ChiselGeneratorAnnotation.elaborate(ChiselAnnotations.scala:55)
	at chisel3.stage.phases.Elaborate.$anonfun$transform$1(Elaborate.scala:19)
	at scala.collection.TraversableLike.$anonfun$flatMap$1(TraversableLike.scala:245)
	at scala.collection.immutable.List.foreach(List.scala:392)
	at scala.collection.TraversableLike.flatMap(TraversableLike.scala:245)
	at scala.collection.TraversableLike.flatMap$(TraversableLike.scala:242)
	at scala.collection.immutable.List.flatMap(List.scala:355)
	at chisel3.stage.phases.Elaborate.transform(Elaborate.scala:18)
	at chisel3.iotesters.setupTreadleBackend$.apply(TreadleBackend.scala:143)
	at chisel3.iotesters.Driver$.$anonfun$execute$2(Driver.scala:53)
	at scala.runtime.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:23)
	at logger.Logger$.$anonfun$makeScope$2(Logger.scala:168)
	at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
	at logger.Logger$.makeScope(Logger.scala:166)
	at logger.Logger$.makeScope(Logger.scala:127)
	at chisel3.iotesters.Driver$.$anonfun$execute$1(Driver.scala:38)
	at scala.runtime.java8.JFunction0$mcZ$sp.apply(JFunction0$mcZ$sp.java:23)
	at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
	at chisel3.iotesters.Driver$.execute(Driver.scala:38)
	at problems.Launcher$.$anonfun$tests$16(Launcher.scala:37)
	at problems.Launcher$.$anonfun$tests$16$adapted(Launcher.scala:35)
	at utils.TutorialRunner$.$anonfun$apply$3(TutorialRunner.scala:56)
	at scala.collection.immutable.List.foreach(List.scala:392)
	at utils.TutorialRunner$.apply(TutorialRunner.scala:47)
	at problems.Launcher$.main(Launcher.scala:104)
	at problems.Launcher.main(Launcher.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sbt.Run.invokeMain(Run.scala:115)
	at sbt.Run.execute$1(Run.scala:79)
	at sbt.Run.$anonfun$runWithLoader$3(Run.scala:84)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at scala.util.Try$.apply(Try.scala:213)
	at sbt.Run.directExecute$1(Run.scala:84)
	at sbt.Run.runWithLoader(Run.scala:93)
	at sbt.Defaults$.$anonfun$bgRunMainTask$7(Defaults.scala:1458)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at scala.util.Try$.apply(Try.scala:213)
	at sbt.internal.BackgroundThreadPool$BackgroundRunnable.run(DefaultBackgroundJobService.scala:360)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:750)
Caused by: java.lang.IndexOutOfBoundsException: 8
	at scala.collection.immutable.Vector.checkRangeConvert(Vector.scala:127)
	at scala.collection.immutable.Vector.apply(Vector.scala:118)
	at chisel3.Vec.apply(Aggregate.scala:251)
	at problems.VecShiftRegisterParam.<init>(VecShiftRegisterParam.scala:24)
	at problems.Launcher$.$anonfun$tests$17(Launcher.scala:36)
	at chisel3.Module$.do_apply(Module.scala:52)
	at chisel3.stage.ChiselGeneratorAnnotation.$anonfun$elaborate$1(ChiselAnnotations.scala:50)
	at chisel3.internal.Builder$.$anonfun$build$1(Builder.scala:408)
	at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
	at chisel3.internal.Builder$.build(Builder.scala:406)
	at chisel3.stage.ChiselGeneratorAnnotation.elaborate(ChiselAnnotations.scala:50)
	... 43 more
================================================================================
Errors: 1: in the following tutorials
Tutorial VecShiftRegisterParam: exception Exception thrown when elaborating ChiselGeneratorAnnotation
================================================================================
2023-08-08 17:46:52,163 shutdown-hooks-run-all ERROR No Log4j 2 configuration file found. Using default configuration (logging only errors to the console), or user programmatically provided configurations. Set system property 'log4j2.debug' to show Log4j 2 internal initialization logging. See https://logging.apache.org/log4j/2.x/manual/configuration.html for instructions on how to configure Log4j 2

정답

// See LICENSE.txt for license details.
package problems

import chisel3._

// Problem:
//
// Implement a parametrized simple shift register.
// 'n' is the number of elements in the shift register.
// 'w' is the width of one element.

class VecShiftRegisterParam(val n: Int, val w: Int) extends Module {
  val io = IO(new Bundle {
    val in  = Input(UInt(w.W))
    val out = Output(UInt(w.W))
  })

  // Implement below ----------
  val shift_reg = Reg(Vec(n, UInt(w.W)))
  for(i <- 1 until n){
    shift_reg(i) := shift_reg(i-1)
  }
  shift_reg(0) := io.in
  io.out := shift_reg(n-1)

}
// Implement above ----------

reg의 index를 n-1로 정정하였고, 통과했다.

What I learned

• Reg 쓸 때, 인덱싱 1 차이 오류에 유의하자.