Add Printable (#270)

Printable is a new type that changes how printing of Chisel types is represented
It uses an ordered collection rather than a format string and specifiers
Features:
 - Custom String Interpolator for Scala-like printf
 - String-like manipulation of "hardware strings" for custom pretty-printing
 - Default pretty-printing for Chisel data types

1 files changed, 39 insertions, 5 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/Printf.scala b/chiselFrontend/src/main/scala/chisel3/core/Printf.scala
index b0a3c955..55197425 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Printf.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Printf.scala
@@ -10,6 +10,24 @@ import chisel3.internal.firrtl._
 import chisel3.internal.sourceinfo.SourceInfo
 
 object printf { // scalastyle:ignore object.name
+  /** Helper for packing escape characters */
+  private[chisel3] def format(formatIn: String): String = {
+    require(formatIn forall (c => c.toInt > 0 && c.toInt < 128),
+      "format strings must comprise non-null ASCII values")
+    def escaped(x: Char) = {
+      require(x.toInt >= 0)
+      if (x == '"' || x == '\\') {
+        s"\\${x}"
+      } else if (x == '\n') {
+        "\\n"
+      } else {
+        require(x.toInt >= 32) // TODO \xNN once FIRRTL issue #59 is resolved
+        x
+      }
+    }
+    formatIn map escaped mkString ""
+  }
+
   /** Prints a message in simulation.
     *
     * Does not fire when in reset (defined as the encapsulating Module's
@@ -23,14 +41,30 @@ object printf { // scalastyle:ignore object.name
     * @param fmt printf format string
     * @param data format string varargs containing data to print
     */
-  def apply(fmt: String, data: Bits*)(implicit sourceInfo: SourceInfo) {
-    when (!(Builder.dynamicContext.currentModule.get.reset)) {
-      printfWithoutReset(fmt, data:_*)
+  def apply(fmt: String, data: Bits*)(implicit sourceInfo: SourceInfo): Unit =
+    apply(Printable.pack(fmt, data:_*))
+  /** Prints a message in simulation.
+    *
+    * Does not fire when in reset (defined as the encapsulating Module's
+    * reset). If your definition of reset is not the encapsulating Module's
+    * reset, you will need to gate this externally.
+    *
+    * May be called outside of a Module (like defined in a function), so
+    * functions using printf make the standard Module assumptions (single clock
+    * and single reset).
+    *
+    * @param pable [[Printable]] to print
+    */
+  def apply(pable: Printable)(implicit sourceInfo: SourceInfo): Unit = {
+    when (!Builder.dynamicContext.currentModule.get.reset) {
+      printfWithoutReset(pable)
     }
   }
 
-  private[core] def printfWithoutReset(fmt: String, data: Bits*)(implicit sourceInfo: SourceInfo) {
+  private[chisel3] def printfWithoutReset(pable: Printable)(implicit sourceInfo: SourceInfo): Unit = {
     val clock = Builder.dynamicContext.currentModule.get.clock
-    pushCommand(Printf(sourceInfo, Node(clock), fmt, data.map((d: Bits) => d.ref)))
+    pushCommand(Printf(sourceInfo, Node(clock), pable))
   }
+  private[chisel3] def printfWithoutReset(fmt: String, data: Bits*)(implicit sourceInfo: SourceInfo): Unit =
+    printfWithoutReset(Printable.pack(fmt, data:_*))
 }