From 3691fe61cc43beb0e7d0f813723d4150daa79372 Mon Sep 17 00:00:00 2001
From: Jiuyang Liu
Date: Thu, 6 May 2021 16:20:50 +0000
Subject: add a simple decoder API.

---
 .../chisel3/util/experimental/decode/decoder.scala | 53 ++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 src/main/scala/chisel3/util/experimental/decode/decoder.scala

(limited to 'src/main/scala/chisel3/util/experimental/decode/decoder.scala')

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
+    }
+  }
+}
-- 
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