1 files changed, 54 insertions, 0 deletions
diff --git a/chiselFrontend/src/main/scala/Chisel/BlackBox.scala b/chiselFrontend/src/main/scala/Chisel/BlackBox.scala
new file mode 100644
index 00000000..be72934d
--- /dev/null
+++ b/chiselFrontend/src/main/scala/Chisel/BlackBox.scala
@@ -0,0 +1,54 @@
+// See LICENSE for license details.
+
+package Chisel
+
+import internal.Builder.pushCommand
+import internal.firrtl.{ModuleIO, DefInvalid}
+
+/** Defines a black box, which is a module that can be referenced from within
+  * Chisel, but is not defined in the emitted Verilog. Useful for connecting
+  * to RTL modules defined outside Chisel.
+  *
+  * @example
+  * {{{
+  * ... to be written once a spec is finalized ...
+  * }}}
+  */
+// REVIEW TODO: make Verilog parameters part of the constructor interface?
+abstract class BlackBox extends Module {
+  // Don't bother taking override_clock|reset, clock/reset locked out anyway
+  // TODO: actually implement this.
+  def setVerilogParameters(s: String): Unit = {}
+
+  // The body of a BlackBox is empty, the real logic happens in firrtl/Emitter.scala
+  // Bypass standard clock, reset, io port declaration by flattening io
+  // TODO(twigg): ? Really, overrides are bad, should extend BaseModule....
+  override private[Chisel] def ports = io.elements.toSeq
+
+  // Do not do reflective naming of internal signals, just name io
+  override private[Chisel] def setRefs(): this.type = {
+    for ((name, port) <- ports) {
+      port.setRef(ModuleIO(this, _namespace.name(name)))
+    }
+    // setRef is not called on the actual io.
+    // There is a risk of user improperly attempting to connect directly with io
+    // Long term solution will be to define BlackBox IO differently as part of
+    //   it not descending from the (current) Module
+    this
+  }
+
+  // Don't setup clock, reset
+  // Cann't invalide io in one bunch, must invalidate each part separately
+  override private[Chisel] def setupInParent(): this.type = _parent match {
+    case Some(p) => {
+      // Just init instance inputs
+      for((_,port) <- ports) pushCommand(DefInvalid(port.ref))
+      this
+    }
+    case None => this
+  }
+
+  // Using null is horrible but these signals SHOULD NEVER be used:
+  override val clock = null
+  override val reset = null
+}