Break out Utils.scala into smaller portions

1 files changed, 69 insertions, 0 deletions

diff --git a/src/main/scala/Chisel/util/Conditional.scala b/src/main/scala/Chisel/util/Conditional.scala
new file mode 100644
index 00000000..b0ac4491
--- /dev/null
+++ b/src/main/scala/Chisel/util/Conditional.scala
@@ -0,0 +1,69 @@
+// See LICENSE for license details.
+
+/** Conditional blocks.
+  */
+
+package Chisel
+
+import scala.language.reflectiveCalls
+import scala.language.experimental.macros
+import scala.reflect.runtime.universe._
+import scala.reflect.macros.blackbox._
+
+/** This is identical to [[Chisel.when when]] with the condition inverted */
+object unless {  // scalastyle:ignore object.name
+  def apply(c: Bool)(block: => Unit) {
+    when (!c) { block }
+  }
+}
+
+class SwitchContext[T <: Bits](cond: T) {
+  def is(v: Iterable[T])(block: => Unit) {
+    if (!v.isEmpty) when (v.map(_.asUInt === cond.asUInt).reduce(_||_)) { block }
+  }
+  def is(v: T)(block: => Unit) { is(Seq(v))(block) }
+  def is(v: T, vr: T*)(block: => Unit) { is(v :: vr.toList)(block) }
+}
+
+/** An object for separate cases in [[Chisel.switch switch]]
+  * It is equivalent to a [[Chisel.when$ when]] block comparing to the condition
+  * Use outside of a switch statement is illegal */
+object is {   // scalastyle:ignore object.name
+  // Begin deprecation of non-type-parameterized is statements.
+  def apply(v: Iterable[Bits])(block: => Unit) {
+    Builder.error("The 'is' keyword may not be used outside of a switch.")
+  }
+
+  def apply(v: Bits)(block: => Unit) {
+    Builder.error("The 'is' keyword may not be used outside of a switch.")
+  }
+
+  def apply(v: Bits, vr: Bits*)(block: => Unit) {
+    Builder.error("The 'is' keyword may not be used outside of a switch.")
+  }
+}
+
+/** Conditional logic to form a switch block
+  * @example
+  * {{{ ... // default values here
+  * switch ( myState ) {
+  *   is( state1 ) {
+  *     ... // some logic here
+  *   }
+  *   is( state2 ) {
+  *     ... // some logic here
+  *   }
+  * } }}}*/
+object switch {  // scalastyle:ignore object.name
+  def apply[T <: Bits](cond: T)(x: => Unit): Unit = macro impl
+  def impl(c: Context)(cond: c.Tree)(x: c.Tree): c.Tree = { import c.universe._
+    val sc = c.universe.internal.reificationSupport.freshTermName("sc")
+    def extractIsStatement(tree: Tree): List[c.universe.Tree] = tree match {
+      case q"Chisel.is.apply( ..$params )( ..$body )" => List(q"$sc.is( ..$params )( ..$body )")
+      case b => throw new Exception(s"Cannot include blocks that do not begin with is() in switch.")
+    }
+    val q"..$body" = x
+    val ises = body.flatMap(extractIsStatement(_))
+    q"""{ val $sc = new SwitchContext($cond); ..$ises }"""
+  }
+}