Add code formatting and update deprecations

.scalafmt.conf

@@ -0,0 +1,26 @@
+version = 2.6.4
+
+maxColumn = 120
+align = most
+continuationIndent.defnSite = 2
+assumeStandardLibraryStripMargin = true
+docstrings = ScalaDoc
+lineEndings = preserve
+includeCurlyBraceInSelectChains = false
+danglingParentheses = true
+
+align.tokens.add = [
+  {
+    code = ":"
+  }
+]
+
+newlines.alwaysBeforeCurlyBraceLambdaParams = false
+newlines.alwaysBeforeMultilineDef = false
+newlines.implicitParamListModifierForce = [before]
+
+verticalMultiline.atDefnSite = true
+
+optIn.annotationNewlines = true
+
+rewrite.rules = [SortImports, PreferCurlyFors, AvoidInfix]

project/plugins.sbt

@@ -1 +1,3 @@
 logLevel := Level.Warn
+
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.3")

src/main/scala/gcd/DecoupledGCD.scala

@@ -13,7 +13,7 @@ class GcdInputBundle(val w: Int) extends Bundle {
 class GcdOutputBundle(val w: Int) extends Bundle {
   val value1 = UInt(w.W)
   val value2 = UInt(w.W)
-  val gcd    = UInt(w.W)
+  val gcd = UInt(w.W)
 }
 
 /**
@@ -27,18 +27,18 @@ class DecoupledGcd(width: Int) extends MultiIOModule {
   val input = IO(Flipped(Decoupled(new GcdInputBundle(width))))
   val output = IO(Decoupled(new GcdOutputBundle(width)))
 
-  val xInitial    = Reg(UInt())
-  val yInitial    = Reg(UInt())
-  val x           = Reg(UInt())
-  val y           = Reg(UInt())
-  val busy        = RegInit(false.B)
+  val xInitial = Reg(UInt())
+  val yInitial = Reg(UInt())
+  val x = Reg(UInt())
+  val y = Reg(UInt())
+  val busy = RegInit(false.B)
   val resultValid = RegInit(false.B)
 
-  input.ready := ! busy
+  input.ready := !busy
   output.valid := resultValid
   output.bits := DontCare
 
-  when(busy)  {
+  when(busy) {
     when(x > y) {
       x := x - y
     }.otherwise {

src/main/scala/gcd/GCD.scala

@@ -11,18 +11,17 @@ import chisel3._
   */
 class GCD extends Module {
   val io = IO(new Bundle {
-    val value1        = Input(UInt(16.W))
-    val value2        = Input(UInt(16.W))
+    val value1 = Input(UInt(16.W))
+    val value2 = Input(UInt(16.W))
     val loadingValues = Input(Bool())
-    val outputGCD     = Output(UInt(16.W))
-    val outputValid   = Output(Bool())
+    val outputGCD = Output(UInt(16.W))
+    val outputValid = Output(Bool())
   })
 
-  val x  = Reg(UInt())
-  val y  = Reg(UInt())
+  val x = Reg(UInt())
+  val y = Reg(UInt())
 
-  when(x > y) { x := x - y }
-    .otherwise { y := y - x }
+  when(x > y) { x := x - y }.otherwise { y := y - x }
 
   when(io.loadingValues) {
     x := io.value1

src/test/scala/gcd/GCDSpec.scala

@@ -3,9 +3,9 @@
 package gcd
 
 import chisel3._
-import chisel3.tester._
-import org.scalatest.FreeSpec
+import chiseltest._
 import chisel3.experimental.BundleLiterals._
+import org.scalatest.freespec.AnyFreeSpec
 
 /**
   * This is a trivial example of how to run this Specification
@@ -18,7 +18,7 @@ import chisel3.experimental.BundleLiterals._
   * sbt 'testOnly gcd.GcdDecoupledTester'
   * }}}
   */
-class GCDSpec extends FreeSpec with ChiselScalatestTester {
+class GCDSpec extends AnyFreeSpec with ChiselScalatestTester {
 
   "Gcd should calculate proper greatest common denominator" in {
     test(new DecoupledGcd(16)) { dut =>
@@ -27,10 +27,11 @@ class GCDSpec extends FreeSpec with ChiselScalatestTester {
       dut.output.initSink()
       dut.output.setSinkClock(dut.clock)
 
-      val testValues = for { x <- 0 to 10; y <- 0 to 10} yield (x, y)
+      val testValues = for { x <- 0 to 10; y <- 0 to 10 } yield (x, y)
       val inputSeq = testValues.map { case (x, y) => (new GcdInputBundle(16)).Lit(_.value1 -> x.U, _.value2 -> y.U) }
-      val resultSeq = testValues.map { case (x, y) =>
-        (new GcdOutputBundle(16)).Lit(_.value1 -> x.U, _.value2 -> y.U, _.gcd -> BigInt(x).gcd(BigInt(y)).U)
+      val resultSeq = testValues.map {
+        case (x, y) =>
+          (new GcdOutputBundle(16)).Lit(_.value1 -> x.U, _.value2 -> y.U, _.gcd -> BigInt(x).gcd(BigInt(y)).U)
       }
 
       fork {