Break Core.scala into bite-sized pieces

1 files changed, 330 insertions, 0 deletions

diff --git a/src/main/scala/Chisel/Aggregate.scala b/src/main/scala/Chisel/Aggregate.scala
new file mode 100644
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+++ b/src/main/scala/Chisel/Aggregate.scala
@@ -0,0 +1,330 @@
+// See LICENSE for license details.
+
+package Chisel
+import scala.collection.immutable.ListMap
+import scala.collection.mutable.{ArrayBuffer, HashSet, LinkedHashMap}
+import Builder.pushCommand
+
+/** An abstract class for data types that solely consist of (are an aggregate
+  * of) other Data objects.
+  */
+sealed abstract class Aggregate(dirArg: Direction) extends Data(dirArg) {
+  private[Chisel] def cloneTypeWidth(width: Width): this.type = cloneType
+  def width: Width = flatten.map(_.width).reduce(_ + _)
+}
+
+object Vec {
+  /** Creates a new [[Vec]] with `n` entries of the specified data type.
+    *
+    * @note elements are NOT assigned by default and have no value
+    */
+  def apply[T <: Data](n: Int, gen: T): Vec[T] = new Vec(gen.cloneType, n)
+
+  @deprecated("Vec argument order should be size, t; this will be removed by the official release", "chisel3")
+  def apply[T <: Data](gen: T, n: Int): Vec[T] = new Vec(gen.cloneType, n)
+
+  /** Creates a new [[Vec]] composed of elements of the input Seq of [[Data]]
+    * nodes.
+    *
+    * @note input elements should be of the same type
+    * @note the width of all output elements is the width of the largest input
+    * element
+    * @note output elements are connected from the input elements
+    */
+  def apply[T <: Data](elts: Seq[T]): Vec[T] = {
+    // REVIEW TODO: error checking to guard against type mismatch?
+
+    require(!elts.isEmpty)
+    val width = elts.map(_.width).reduce(_ max _)
+    val vec = new Vec(elts.head.cloneTypeWidth(width), elts.length)
+    pushCommand(DefWire(vec))
+    for ((v, e) <- vec zip elts)
+      v := e
+    vec
+  }
+
+  /** Creates a new [[Vec]] composed of the input [[Data]] nodes.
+    *
+    * @note input elements should be of the same type
+    * @note the width of all output elements is the width of the largest input
+    * element
+    * @note output elements are connected from the input elements
+    */
+  def apply[T <: Data](elt0: T, elts: T*): Vec[T] =
+    // REVIEW TODO: does this really need to exist as a standard function?
+    apply(elt0 +: elts.toSeq)
+
+  /** Creates a new [[Vec]] of length `n` composed of the results of the given
+    * function applied over a range of integer values starting from 0.
+    *
+    * @param n number of elements in the vector (the function is applied from
+    * 0 to `n-1`)
+    * @param gen function that takes in an Int (the index) and returns a
+    * [[Data]] that becomes the output element
+    */
+  def tabulate[T <: Data](n: Int)(gen: (Int) => T): Vec[T] =
+    apply((0 until n).map(i => gen(i)))
+
+  /** Creates a new [[Vec]] of length `n` composed of the result of the given
+    * function repeatedly applied.
+    *
+    * @param n number of elements (amd the number of times the function is
+    * called)
+    * @param gen function that generates the [[Data]] that becomes the output
+    * element
+    */
+  def fill[T <: Data](n: Int)(gen: => T): Vec[T] = apply(Seq.fill(n)(gen))
+}
+
+/** A vector (array) of [[Data]] elements. Provides hardware versions of various
+  * collection transformation functions found in software array implementations.
+  *
+  * @tparam T type of elements
+  */
+sealed class Vec[T <: Data] private (gen: => T, val length: Int)
+    extends Aggregate(gen.dir) with VecLike[T] {
+  // REVIEW TODO: should this take a Seq instead of a gen()?
+
+  private val self = IndexedSeq.fill(length)(gen)
+
+  override def <> (that: Data): Unit = that match {
+    case _: Vec[_] => this bulkConnect that
+    case _ => this badConnect that
+  }
+
+  def <> (that: Seq[T]): Unit =
+    // REVIEW TODO: come up with common style: match on type in body or
+    // multiple invocation signatures
+    for ((a, b) <- this zip that)
+      a <> b
+
+  def <> (that: Vec[T]): Unit = this bulkConnect that
+    // REVIEW TODO: standardize as above
+
+  override def := (that: Data): Unit = that match {
+    case _: Vec[_] => this connect that
+    case _ => this badConnect that
+  }
+
+  def := (that: Seq[T]): Unit = {
+    // REVIEW TODO: standardize as above
+    require(this.length == that.length)
+    for ((a, b) <- this zip that)
+      a := b
+  }
+
+  def := (that: Vec[T]): Unit = this connect that
+
+  /** Creates a dynamically indexed read accessor into the array. Generates
+    * logic (likely some kind of multiplexer).
+    */
+  def apply(idx: UInt): T = {
+    val x = gen
+    // REVIEW TODO: what happens when people try to assign into this?
+    // Should this be a read-only reference?
+    pushCommand(DefAccessor(x, Node(this), NO_DIR, idx.ref))
+    x
+  }
+
+  /** Creates a statically indexed read accessor into the array. Generates no
+    * logic.
+    */
+  def apply(idx: Int): T = self(idx)
+
+  def read(idx: UInt): T = apply(idx)
+  // REVIEW TODO: does this need to exist?
+
+  def write(idx: UInt, data: T): Unit = apply(idx) := data
+
+  override def cloneType: this.type =
+    Vec(gen, length).asInstanceOf[this.type]
+
+  private val t = gen
+  private[Chisel] def toType: String = s"${t.toType}[$length]"
+  private[Chisel] lazy val flatten: IndexedSeq[Bits] =
+    (0 until length).flatMap(i => this.apply(i).flatten)
+
+  for ((elt, i) <- self zipWithIndex)
+    elt.setRef(this, i)
+}
+
+/** A trait for [[Vec]]s containing common hardware generators for collection
+  * operations.
+  */
+trait VecLike[T <: Data] extends collection.IndexedSeq[T] {
+  def read(idx: UInt): T
+  // REVIEW TODO: does this need to exist? (does the same thing as apply)
+
+  def write(idx: UInt, data: T): Unit
+  def apply(idx: UInt): T
+
+  /** Outputs true if p outputs true for every element.
+    *
+    * This generates into a function evaluation followed by a logical AND
+    * reduction.
+    */
+  def forall(p: T => Bool): Bool = (this map p).fold(Bool(true))(_ && _)
+
+  /** Outputs true if p outputs true for at least one element.
+    *
+    * This generates into a function evaluation followed by a logical OR
+    * reduction.
+    */
+  def exists(p: T => Bool): Bool = (this map p).fold(Bool(false))(_ || _)
+
+  /** Outputs true if the vector contains at least one element equal to x (using
+    * the === operator).
+    *
+    * This generates into an equality comparison followed by a logical OR
+    * reduction.
+    */
+  def contains(x: T)(implicit evidence: T <:< UInt): Bool = this.exists(_ === x)
+
+  /** Outputs the number of elements for which p is true.
+    *
+    * This generates into a function evaluation followed by a set bit counter.
+    */
+  def count(p: T => Bool): UInt = PopCount((this map p).toSeq)
+
+  /** Helper function that appends an index (literal value) to each element,
+    * useful for hardware generators which output an index.
+    */
+  private def indexWhereHelper(p: T => Bool) = this map p zip (0 until length).map(i => UInt(i))
+
+  /** Outputs the index of the first element for which p outputs true.
+    *
+    * This generates into a function evaluation followed by a priority mux.
+    */
+  def indexWhere(p: T => Bool): UInt = PriorityMux(indexWhereHelper(p))
+
+  /** Outputs the index of the last element for which p outputs true.
+    *
+    * This generates into a function evaluation followed by a priority mux.
+    */
+  def lastIndexWhere(p: T => Bool): UInt = PriorityMux(indexWhereHelper(p).reverse)
+
+  /** Outputs the index of the element for which p outputs true, assuming that
+    * the there is exactly one such element.
+    *
+    * This generates into a function evaluation followed by a one-hot mux. The
+    * implementation may be more efficient than a priority mux, but incorrect
+    * results are possible if there is not exactly one true element.
+    */
+  def onlyIndexWhere(p: T => Bool): UInt = Mux1H(indexWhereHelper(p))
+  // REVIEW TODO: can (should?) this be assertion checked?
+}
+
+/** Base class for data types defined as a bundle of other data types.
+  *
+  * Usage: extend this class (either as an anonymous or named class) and define
+  * members variables of [[Data]] subtypes to be elements in the Bundle.
+  */
+class Bundle extends Aggregate(NO_DIR) {
+  private val _namespace = Builder.globalNamespace.child
+
+  // REVIEW TODO: perhaps deprecate to match FIRRTL semantics? Also needs
+  // strong connect operator.
+  /** Connect elements in this Bundle to elements in `that` on a best-effort
+    * (weak) basis, matching by type, orientation, and name.
+    *
+    * @note unconnected elements will NOT generate errors or warnings
+    *
+    * @example
+    * {{{
+    * // Pass through wires in this module's io to those mySubModule's io,
+    * // matching by type, orientation, and name, and ignoring extra wires.
+    * mySubModule.io <> io
+    * }}}
+    */
+  override def <> (that: Data): Unit = that match {
+    case _: Bundle => this bulkConnect that
+    case _ => this badConnect that
+  }
+
+  // REVIEW TODO: should there be different semantics for this? Or just ban it?
+  override def := (that: Data): Unit = this <> that
+
+  lazy val elements: ListMap[String, Data] = ListMap(namedElts:_*)
+
+  /** Returns a best guess at whether a field in this Bundle is a user-defined
+    * Bundle element.
+    */
+  private def isBundleField(m: java.lang.reflect.Method) =
+    m.getParameterTypes.isEmpty &&
+    !java.lang.reflect.Modifier.isStatic(m.getModifiers) &&
+    classOf[Data].isAssignableFrom(m.getReturnType) &&
+    !(Bundle.keywords contains m.getName) && !(m.getName contains '$')
+
+  /** Returns a list of elements in this Bundle.
+    */
+  private[Chisel] lazy val namedElts = {
+    val nameMap = LinkedHashMap[String, Data]()
+    val seen = HashSet[Data]()
+    for (m <- getClass.getMethods.sortWith(_.getName < _.getName); if isBundleField(m)) {
+      m.invoke(this) match {
+        case d: Data =>
+          if (nameMap contains m.getName) {
+            require(nameMap(m.getName) eq d)
+          } else if (!seen(d)) {
+            nameMap(m.getName) = d; seen += d
+          }
+        case _ =>
+      }
+    }
+    ArrayBuffer(nameMap.toSeq:_*) sortWith {case ((an, a), (bn, b)) => (a._id > b._id) || ((a eq b) && (an > bn))}
+  }
+  private[Chisel] def toType = {
+    def eltPort(elt: Data): String = {
+      val flipStr = if (elt.isFlip) "flip " else ""
+      s"${flipStr}${elt.getRef.name} : ${elt.toType}"
+    }
+    s"{${namedElts.reverse.map(e => eltPort(e._2)).mkString(", ")}}"
+  }
+  private[Chisel] lazy val flatten = namedElts.flatMap(_._2.flatten)
+  private[Chisel] def addElt(name: String, elt: Data): Unit =
+    namedElts += name -> elt
+  private[Chisel] override def _onModuleClose: Unit =
+    for ((name, elt) <- namedElts) { elt.setRef(this, _namespace.name(name)) }
+
+  override def cloneType : this.type = {
+    // If the user did not provide a cloneType method, try invoking one of
+    // the following constructors, not all of which necessarily exist:
+    // - A zero-parameter constructor
+    // - A one-paramater constructor, with null as the argument
+    // - A one-parameter constructor for a nested Bundle, with the enclosing
+    //   parent Module as the argument
+    val constructor = this.getClass.getConstructors.head
+    try {
+      val args = Seq.fill(constructor.getParameterTypes.size)(null)
+      constructor.newInstance(args:_*).asInstanceOf[this.type]
+    } catch {
+      case e: java.lang.reflect.InvocationTargetException if e.getCause.isInstanceOf[java.lang.NullPointerException] =>
+        try {
+          constructor.newInstance(_parent.get).asInstanceOf[this.type]
+        } catch {
+          case _: java.lang.reflect.InvocationTargetException =>
+            Builder.error(s"Parameterized Bundle ${this.getClass} needs cloneType method. You are probably using " +
+              "an anonymous Bundle object that captures external state and hence is un-cloneTypeable")
+            this
+        }
+      case _: java.lang.reflect.InvocationTargetException | _: java.lang.IllegalArgumentException =>
+        Builder.error(s"Parameterized Bundle ${this.getClass} needs cloneType method")
+        this
+    }
+  }
+}
+
+object Bundle {
+  private val keywords =
+    HashSet[String]("flip", "asInput", "asOutput", "cloneType", "toBits")
+
+  def apply[T <: Bundle](b: => T)(implicit p: Parameters): T = {
+    Builder.paramsScope(p.push){ b }
+  }
+
+  //TODO @deprecated("Use Chisel.paramsScope object","08-01-2015")
+  def apply[T <: Bundle](b: => T,  f: PartialFunction[Any,Any]): T = {
+    val q = Builder.getParams.alterPartial(f)
+    apply(b)(q)
+  }
+}