Merge pull request #109 from ucb-bar/Fix-init-in-DeqIO

Fix init in deq io

1 files changed, 34 insertions, 7 deletions

diff --git a/src/main/scala/Chisel/util/Decoupled.scala b/src/main/scala/Chisel/util/Decoupled.scala
index 23a08d52..ba33e6c7 100644
--- a/src/main/scala/Chisel/util/Decoupled.scala
+++ b/src/main/scala/Chisel/util/Decoupled.scala
@@ -22,21 +22,48 @@ object Decoupled {
   def apply[T <: Data](gen: T): DecoupledIO[T] = new DecoupledIO(gen)
 }
 
-/** An I/O bundle for enqueuing data with valid/ready handshaking */
+/** An I/O bundle for enqueuing data with valid/ready handshaking
+  * Initialization must be handled, if necessary, by the parent circuit
+  */
 class EnqIO[T <: Data](gen: T) extends DecoupledIO(gen)
 {
+  /** push dat onto the output bits of this interface to let the consumer know it has happened.
+    * @param dat the values to assign to bits.
+    * @return    dat.
+    */
   def enq(dat: T): T = { valid := Bool(true); bits := dat; dat }
-  valid := Bool(false)
-  for (io <- bits.flatten)
-    io := UInt(0)
+
+  /** Initialize this Bundle.  Valid is set to false, and all bits are set to zero.
+    * NOTE: This method of initialization is still being discussed and could change in the
+    * future.
+    */
+  def init(): Unit = {
+    valid := Bool(false)
+    for (io <- bits.flatten)
+      io := UInt(0)
+  }
   override def cloneType: this.type = { new EnqIO(gen).asInstanceOf[this.type]; }
 }
 
-/** An I/O bundle for dequeuing data with valid/ready handshaking */
+/** An I/O bundle for dequeuing data with valid/ready handshaking.
+  * Initialization must be handled, if necessary, by the parent circuit
+  */
 class DeqIO[T <: Data](gen: T) extends DecoupledIO(gen) with Flipped
 {
-  ready := Bool(false)
+  /** Assert ready on this port and return the associated data bits.
+    * This is typically used when valid has been asserted by the producer side.
+    * @param b ignored
+    * @return the data for this device,
+    */
   def deq(b: Boolean = false): T = { ready := Bool(true); bits }
+
+  /** Initialize this Bundle.
+    * NOTE: This method of initialization is still being discussed and could change in the
+    * future.
+    */
+  def init(): Unit = {
+    ready := Bool(false)
+  }
   override def cloneType: this.type = { new DeqIO(gen).asInstanceOf[this.type]; }
 }
 
@@ -54,7 +81,7 @@ class DecoupledIOC[+T <: Data](gen: T) extends Bundle
 class QueueIO[T <: Data](gen: T, entries: Int) extends Bundle
 {
   /** I/O to enqueue data, is [[Chisel.DecoupledIO]] flipped */
-  val enq   = Decoupled(gen.cloneType).flip
+  val enq   = Decoupled(gen.cloneType).flip()
   /** I/O to enqueue data, is [[Chisel.DecoupledIO]]*/
   val deq   = Decoupled(gen.cloneType)
   /** The current amount of data in the queue */