Update toPrintable for Enums (#2707) (#2763)

(cherry picked from commit 0ff99ca8d573e3487ef496a21c95d962689c3cba)

Co-authored-by: Aditya Naik <91489422+adkian-sifive@users.noreply.github.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/core/src/main/scala/chisel3/StrongEnum.scala b/core/src/main/scala/chisel3/StrongEnum.scala
index 6d8ceb2f..3c9f4105 100644
--- a/core/src/main/scala/chisel3/StrongEnum.scala
+++ b/core/src/main/scala/chisel3/StrongEnum.scala
@@ -251,7 +251,28 @@ abstract class EnumType(private[chisel3] val factory: EnumFactory, selfAnnotatin
 
   protected def enumTypeName: String = factory.enumTypeName
 
-  def toPrintable: Printable = FullName(this) // TODO: Find a better pretty printer
+  def toPrintable: Printable = {
+    implicit val sourceInfo = UnlocatableSourceInfo
+    implicit val compileOptions = ExplicitCompileOptions.Strict
+    val allNames = factory.allNames.zip(factory.all)
+    val nameSize = allNames.map(_._1.length).max
+    def leftPad(str: String): String = {
+      str.reverse.padTo(nameSize, ' ').reverse
+    }
+    val allNamesPadded = allNames.map { case (name, value) => leftPad(name) -> value }
+
+    val result = Wire(Vec(nameSize, UInt(8.W))).suggestName(s"_${enumTypeName}Printable")
+    result.foreach(_ := '?'.U)
+
+    for ((name, value) <- allNamesPadded) {
+      when(this === value) {
+        for ((r, c) <- result.zip(name)) {
+          r := c.toChar.U
+        }
+      }
+    }
+    result.map(Character(_)).foldLeft(p"")(_ + _)
+  }
 }
 
 abstract class EnumFactory {
@@ -284,6 +305,8 @@ abstract class EnumFactory {
   def getWidth: Int = width.get
 
   def all: Seq[Type] = enumInstances
+  /* Accessor for Seq of names in enumRecords */
+  def allNames: Seq[String] = enumNames
 
   private[chisel3] def nameOfValue(id: BigInt): Option[String] = {
     enumRecords.find(_.inst.litValue == id).map(_.name)