Decoupled: cast DecoupledIO to IrrevocableIO as an input (#280)

1 files changed, 13 insertions, 0 deletions

diff --git a/src/main/scala/chisel3/util/Decoupled.scala b/src/main/scala/chisel3/util/Decoupled.scala
index b2634bec..77990777 100644
--- a/src/main/scala/chisel3/util/Decoupled.scala
+++ b/src/main/scala/chisel3/util/Decoupled.scala
@@ -66,6 +66,19 @@ class IrrevocableIO[+T <: Data](gen: T) extends ReadyValidIO[T](gen)
 object Irrevocable
 {
   def apply[T <: Data](gen: T): IrrevocableIO[T] = new IrrevocableIO(gen)
+
+  /** Take a DecoupledIO and cast it to an IrrevocableIO.
+    * This cast is only safe to do in cases where the IrrevocableIO
+    * is being consumed as an input.
+    */
+  def apply[T <: Data](dec: DecoupledIO[T]): IrrevocableIO[T] = {
+    require(dec.bits.dir == INPUT, "Only safe to cast consumed Decoupled bits to Irrevocable.")
+    val i = Wire(new IrrevocableIO(dec.bits))
+    dec.bits := i.bits
+    dec.valid := i.valid
+    i.ready := dec.ready
+    i
+  }
 }