From 0a2a93c27dbf26f2d27f9750b2008a4d93084188 Mon Sep 17 00:00:00 2001
From: "Wesley W. Terpstra" <wesley@sifive.com>
Date: Fri, 19 May 2017 14:34:54 -0700
Subject: [PATCH] diplomacy: add the new Splitter node type

---
 src/main/scala/diplomacy/Nodes.scala | 39 ++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/src/main/scala/diplomacy/Nodes.scala b/src/main/scala/diplomacy/Nodes.scala
index d2ae7165..e160e3b1 100644
--- a/src/main/scala/diplomacy/Nodes.scala
+++ b/src/main/scala/diplomacy/Nodes.scala
@@ -339,6 +339,45 @@ class NexusNode[D, U, EO, EI, B <: Data](imp: NodeImp[D, U, EO, EI, B])(
   numPI: Range.Inclusive = 1 to 999)
     extends MixedNexusNode[D, U, EI, B, D, U, EO, B](imp, imp)(dFn, uFn, numPO, numPI)
 
+case class SplitterArg[T](newSize: Int, ports: Seq[T])
+class MixedSplitterNode[DI, UI, EI, BI <: Data, DO, UO, EO, BO <: Data](
+  inner: InwardNodeImp [DI, UI, EI, BI],
+  outer: OutwardNodeImp[DO, UO, EO, BO])(
+  dFn: SplitterArg[DI] => Seq[DO],
+  uFn: SplitterArg[UO] => Seq[UI],
+  numPO: Range.Inclusive = 1 to 999,
+  numPI: Range.Inclusive = 1 to 999)
+  extends MixedNode(inner, outer)(numPO, numPI)
+{
+  override val externalIn: Boolean = true
+  override val externalOut: Boolean = true
+
+  protected[diplomacy] def resolveStar(iKnown: Int, oKnown: Int, iStars: Int, oStars: Int): (Int, Int) = {
+    require (oKnown == 0, s"${name} (a splitter) appears right of a := or :*=; use a :=* instead${lazyModule.line}")
+    require (iStars == 0, s"${name} (a splitter) cannot appear left of a :*=; did you mean :=*?${lazyModule.line}")
+    (0, iKnown)
+  }
+  protected[diplomacy] def mapParamsD(n: Int, p: Seq[DI]): Seq[DO] = {
+    require (p.size == 0 || n % p.size == 0, s"Diplomacy bug; splitter inputs do not divide outputs")
+    val out = dFn(SplitterArg(n, p))
+    require (out.size == n, s"${name} created the wrong number of outputs from inputs${lazyModule.line}")
+    out
+  }
+  protected[diplomacy] def mapParamsU(n: Int, p: Seq[UO]): Seq[UI] = {
+    require (n == 0 || p.size % n == 0, s"Diplomacy bug; splitter outputs indivisable by inputs")
+    val out = uFn(SplitterArg(n, p))
+    require (out.size == n, s"${name} created the wrong number of inputs from outputs${lazyModule.line}")
+    out
+  }
+}
+
+class SplitterNode[D, U, EO, EI, B <: Data](imp: NodeImp[D, U, EO, EI, B])(
+  dFn: SplitterArg[D] => Seq[D],
+  uFn: SplitterArg[U] => Seq[U],
+  numPO: Range.Inclusive = 1 to 999,
+  numPI: Range.Inclusive = 1 to 999)
+    extends MixedSplitterNode[D, U, EI, B, D, U, EO, B](imp, imp)(dFn, uFn, numPO, numPI)
+
 class IdentityNode[D, U, EO, EI, B <: Data](imp: NodeImp[D, U, EO, EI, B])
   extends AdapterNode(imp)({s => s}, {s => s})