Merge branch 'master' into 3.5-release

1 files changed, 83 insertions, 0 deletions

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..42e374d1
--- /dev/null
+++ b/src/main/scala/chisel3/util/experimental/decode/decoder.scala
@@ -0,0 +1,83 @@
+// 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 {
+  /** Use a specific [[Minimizer]] to generated decoded signals.
+    *
+    * @param minimizer  specific [[Minimizer]], can be [[QMCMinimizer]] or [[EspressoMinimizer]].
+    * @param input      input signal that contains decode table input
+    * @param truthTable [[TruthTable]] to decode user input.
+    * @return decode table output.
+    */
+  def apply(minimizer: Minimizer, input: UInt, truthTable: TruthTable): UInt = {
+    val minimizedTable = getAnnotations().collect {
+      case DecodeTableAnnotation(_, in, out) => TruthTable(in) -> TruthTable(out)
+    }.toMap.getOrElse(truthTable, minimizer.minimize(truthTable))
+    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
+    }
+  }
+
+  /** Use [[EspressoMinimizer]] to generated decoded signals.
+    *
+    * @param input      input signal that contains decode table input
+    * @param truthTable [[TruthTable]] to decode user input.
+    * @return decode table output.
+    */
+  def espresso(input: UInt, truthTable: TruthTable): UInt = apply(EspressoMinimizer, input, truthTable)
+
+  /** Use [[QMCMinimizer]] to generated decoded signals.
+    *
+    * @param input      input signal that contains decode table input
+    * @param truthTable [[TruthTable]] to decode user input.
+    * @return decode table output.
+    */
+  def qmc(input: UInt, truthTable: TruthTable): UInt = apply(QMCMinimizer, input, truthTable)
+
+  /** try to use [[EspressoMinimizer]] to decode `input` by `truthTable`
+    * if `espresso` not exist in your PATH environment it will fall back to [[QMCMinimizer]], and print a warning.
+    *
+    * @param input      input signal that contains decode table input
+    * @param truthTable [[TruthTable]] to decode user input.
+    * @return decode table output.
+    */
+  def apply(input: UInt, truthTable: TruthTable): UInt = {
+    def qmcFallBack(input: UInt, truthTable: TruthTable) = {
+      """fall back to QMC.
+        |Quine-McCluskey is a NP complete algorithm, may run forever or run out of memory in large decode tables.
+        |To get rid of this warning, please use `decoder.qmc` directly, or add espresso to your PATH.
+        |""".stripMargin
+      qmc(input, truthTable)
+    }
+
+    try espresso(input, truthTable) catch {
+      case EspressoNotFoundException =>
+        logger.error(s"espresso is not found in your PATH:\n${sys.env("PATH").split(":").mkString("\n")}".stripMargin)
+        qmcFallBack(input, truthTable)
+      case e: java.io.IOException =>
+        logger.error(s"espresso failed to run with ${e.getMessage}")
+        qmcFallBack(input, truthTable)
+    }
+  }
+}