add a simple decoder API.

2 files changed, 55 insertions, 2 deletions

diff --git a/src/main/scala/chisel3/util/experimental/decode/DecodeTableAnnotation.scala b/src/main/scala/chisel3/util/experimental/decode/DecodeTableAnnotation.scala
index 3a6957e2..cd289a5d 100644
--- a/src/main/scala/chisel3/util/experimental/decode/DecodeTableAnnotation.scala
+++ b/src/main/scala/chisel3/util/experimental/decode/DecodeTableAnnotation.scala
@@ -6,8 +6,8 @@ import firrtl.annotations.{Annotation, ReferenceTarget, SingleTargetAnnotation}
 
 case class DecodeTableAnnotation(
   target:         ReferenceTarget,
-  truthTable:     TruthTable,
-  minimizedTable: TruthTable)
+  truthTable:     String,
+  minimizedTable: String)
     extends SingleTargetAnnotation[ReferenceTarget] {
   override def duplicate(n: ReferenceTarget): Annotation = this.copy(target = n)
 }
diff --git a/src/main/scala/chisel3/util/experimental/decode/decoder.scala b/src/main/scala/chisel3/util/experimental/decode/decoder.scala
new file mode 100644
index 00000000..2ef474e1
--- /dev/null
+++ b/src/main/scala/chisel3/util/experimental/decode/decoder.scala
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package chisel3.util.experimental.decode
+
+import chisel3._
+import chisel3.experimental.{ChiselAnnotation, annotate}
+import chisel3.util.{BitPat, pla}
+import chisel3.util.experimental.getAnnotations
+import firrtl.annotations.Annotation
+import logger.LazyLogging
+
+object decoder extends LazyLogging {
+  def apply(minimizer: Minimizer, input: UInt, truthTable: TruthTable): UInt = {
+    val minimizedTable = getAnnotations().collect {
+      case DecodeTableAnnotation(_, in, out) => TruthTable(in) -> TruthTable(out)
+    }.toMap.getOrElse(
+      {
+        logger.trace(s"""Decoder Cache Hit!
+                        |${truthTable.table}
+                        |""".stripMargin)
+        truthTable
+      }, {
+        val startTime = System.nanoTime()
+        val minimizedTable = minimizer.minimize(truthTable)
+        val totalTime = System.nanoTime() - startTime
+        val totalTimeInSeconds = totalTime / 1e9
+        val info = f"Logic Minimize with $minimizer finished in ${totalTimeInSeconds} second"
+        if (totalTimeInSeconds > 5)
+          logger.error(
+            s"$info spends too long, consider using chisel3.util.experimental.DecodeTableAnnotation to cache decode result or switch to EspressoMinimizer."
+          )
+        else logger.trace(info)
+        minimizedTable
+      }
+    )
+    if (minimizedTable.table.isEmpty) {
+      val outputs = Wire(UInt(minimizedTable.default.getWidth.W))
+      outputs := minimizedTable.default.value.U(minimizedTable.default.getWidth.W)
+      outputs
+    } else {
+      val (plaInput, plaOutput) =
+        pla(minimizedTable.table.toSeq, BitPat(minimizedTable.default.value.U(minimizedTable.default.getWidth.W)))
+
+      annotate(new ChiselAnnotation {
+        override def toFirrtl: Annotation =
+          DecodeTableAnnotation(plaOutput.toTarget, truthTable.toString, minimizedTable.toString)
+      })
+
+      plaInput := input
+      plaOutput
+    }
+  }
+}