1 files changed, 44 insertions, 0 deletions
diff --git a/src/main/scala/firrtl/constraint/IsKnown.scala b/src/main/scala/firrtl/constraint/IsKnown.scala
new file mode 100644
index 00000000..5bd25f92
--- /dev/null
+++ b/src/main/scala/firrtl/constraint/IsKnown.scala
@@ -0,0 +1,44 @@
+// See LICENSE for license details.
+
+package firrtl.constraint
+
+object IsKnown {
+  def unapply(b: Constraint): Option[BigDecimal] = b match {
+    case k: IsKnown => Some(k.value)
+    case _ => None
+  }
+}
+
+/** Constant values must extend this trait see [[firrtl.ir.Closed and firrtl.ir.Open]] */
+trait IsKnown extends Constraint {
+  val value: BigDecimal
+
+  /** Addition */
+  def +(that: IsKnown): IsKnown
+
+  /** Multiplication */
+  def *(that: IsKnown): IsKnown
+
+  /** Max */
+  def max(that: IsKnown): IsKnown
+
+  /** Min */
+  def min(that: IsKnown): IsKnown
+
+  /** Negate */
+  def neg: IsKnown
+
+  /** 2 << value */
+  def pow: IsKnown
+
+  /** Floor */
+  def floor: IsKnown
+
+  override def map(f: Constraint=>Constraint): Constraint = this
+
+  val children: Vector[Constraint] = Vector.empty[Constraint]
+
+  def reduce(): IsKnown = this
+}
+
+