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-rw-r--r--src/main/scala/chisel3/util/Decoupled.scala9
-rw-r--r--src/test/scala/chiselTests/DecoupledSpec.scala19
2 files changed, 28 insertions, 0 deletions
diff --git a/src/main/scala/chisel3/util/Decoupled.scala b/src/main/scala/chisel3/util/Decoupled.scala
index 6a3aad24..82511ee5 100644
--- a/src/main/scala/chisel3/util/Decoupled.scala
+++ b/src/main/scala/chisel3/util/Decoupled.scala
@@ -92,6 +92,15 @@ object Decoupled
/** Wraps some Data with a DecoupledIO interface. */
def apply[T <: Data](gen: T): DecoupledIO[T] = new DecoupledIO(gen)
+ // TODO: use a proper empty data type, this is a quick and dirty solution
+ private final class EmptyBundle extends Bundle
+
+ // Both of these methods return DecoupledIO parameterized by the most generic type: Data
+ /** Returns a [[DecoupledIO]] inteface with no payload */
+ def apply(): DecoupledIO[Data] = apply(new EmptyBundle)
+ /** Returns a [[DecoupledIO]] inteface with no payload */
+ def empty: DecoupledIO[Data] = Decoupled()
+
/** Downconverts an IrrevocableIO output to a DecoupledIO, dropping guarantees of irrevocability.
*
* @note unsafe (and will error) on the producer (input) side of an IrrevocableIO
diff --git a/src/test/scala/chiselTests/DecoupledSpec.scala b/src/test/scala/chiselTests/DecoupledSpec.scala
new file mode 100644
index 00000000..c251df82
--- /dev/null
+++ b/src/test/scala/chiselTests/DecoupledSpec.scala
@@ -0,0 +1,19 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import chisel3._
+import chisel3.util.Decoupled
+
+class DecoupledSpec extends ChiselFlatSpec {
+ "Decoupled() and Decoupled.empty" should "give DecoupledIO with empty payloads" in {
+ elaborate(new Module {
+ val io = IO(new Bundle {
+ val in = Flipped(Decoupled())
+ val out = Decoupled.empty
+ })
+ io.out <> io.in
+ assert(io.asUInt.widthOption.get === 4)
+ })
+ }
+}