Add fixed point type (#322)

* WIP: Adding FixedType to Firrtl proper

Got simple example running through width inference
Checks should be ok
Need to look into FixedLiteral more

* Added simple test for fixed types

* Added asFixedPoint to primops

* Added tail case for FixedType

* Added ConvertFixedToSInt.scala

Added pass to MiddleToLowerFirrtl transform

* Replace AsFixedType with AsSInt in fixed removal

* Bugfix: constant from asFixed not deleted

* Added unit test for bulk connect

* Fixed partial connect bug #241

* Fixed missing case for FixedPoint in legalizeConnect

* Add FixedMathSpec that demonstrates some problems with FixedPointMath

* Fixed test and ConvertToSInt to pass.

Negative binary points not easily supported, needs much more time to
implement.

* Refactored checking neg widths

Make checking for negative binary points easier

* Added tests for inferring many FixedType ops

shl, shr, cat, bits, head, tail, setbp, shiftbp

* Handle bpshl, bpshr, bpset in ConvertFixedToSInt

Changed name from shiftbp -> bpshl, bpshr
Change name from setbp -> bpset
Added more tests

* Added set binary point test that fails

* Added simple test for zero binary point

* gitignore fixes for antlr intermediate dir and intellij dir

* removed unused imports
retool the fixed point with zero binary point test

* simplified example of inability to set binary point to zero

* Temporary fix for zero-width binary point

This fix allows for all widths to be zero, but since this is a feature I
am working on next, I'm not going to bother with a more stringent check.

* change version for dsp tools

* Removed extra temporary file

* Fixed merge bug

* Fixed another merge bug

* Removed commented out/unrelated files

* Removed snake case

1 files changed, 6 insertions, 7 deletions

diff --git a/src/main/scala/firrtl/passes/CheckChirrtl.scala b/src/main/scala/firrtl/passes/CheckChirrtl.scala
index 17e228eb..504702b5 100644
--- a/src/main/scala/firrtl/passes/CheckChirrtl.scala
+++ b/src/main/scala/firrtl/passes/CheckChirrtl.scala
@@ -68,22 +68,21 @@ object CheckChirrtl extends Pass {
         errors append new InvalidLOCException(info, mname)
       case _ => // Do Nothing
     }
-
     def checkChirrtlW(info: Info, mname: String)(w: Width): Width = w match {
-      case w: IntWidth if w.width <= 0 =>
-        errors append new NegWidthException(info, mname)
+      case w: IntWidth if (w.width < BigInt(0)) =>
+        errors.append(new NegWidthException(info, mname))
         w
       case _ => w
     }
 
-    def checkChirrtlT(info: Info, mname: String)(t: Type): Type = {
+    def checkChirrtlT(info: Info, mname: String)(t: Type): Type =
       t map checkChirrtlT(info, mname) match {
         case t: VectorType if t.size < 0 =>
           errors append new NegVecSizeException(info, mname)
-        case _ => // Do nothing
+          t map checkChirrtlW(info, mname)
+        //case FixedType(width, point) => FixedType(checkChirrtlW(width), point)
+        case _ => t map checkChirrtlW(info, mname)
       }
-      t map checkChirrtlW(info, mname) map checkChirrtlT(info, mname)
-    }
 
     def validSubexp(info: Info, mname: String)(e: Expression): Expression = {
       e match {