Interval Data Type Support for Chisel (#1210)

Plan to be released with 3.3.

Breaks experimental Range API.
Adds new Interval type and associated support.

This commit adds the following:

- Renamed Range to IntervalRange to avoid name collision with scala Range
- Changed RangeTransform macro to Return an IntervalRange
  - Improved error messages on missing comma or decimal
  - Added notational support for binary point
  - Some formatting cleanup also
- SIntFactory
  - Change to use IntervalRange API
- UIntFactory
  - UInt from range has custom width computation
    - It does not need to deal with lowerbound extending bit requirements
    - Code to handle special case of range"[0,0]" to have a width of 1
- IR.scala
  - Removed Bound and other constraint code that was duplicating firrtl stuff
  - Added new RangeType
  - Added IntervalRange class and object
- RangeSpec
  - modified just a bit to handle notational differences
    - previous range interpolator returned tuple now returns IntervalRange
- Add IntervalType to emitter
- Added IntervalSpec with many tests
- Added ScalaIntervalSimulatorSpec which tests golden model for Interval
- Added ScalaIntervalSimulator which is a golden model for Interval
  - This gold may not have been polished to a high sheen
- Add IntervalLit cases to Converter
- Add Interval PrimOps to IR
  - asInterval, wrap, squz, clip, setp, decp, incp
  - Add IntervalLit class to IR
- Add Interval to MonoConnect
- Add Interval Type to Bits (in experimental package)
  - add conversions to Interval from other types
- Add Interval clone stuff to Data
- Add Literal creation helpers to chisel3 package
  - these may move to experimental if I can figure that out

1 files changed, 52 insertions, 0 deletions

diff --git a/src/test/scala/chiselTests/Util.scala b/src/test/scala/chiselTests/Util.scala
index f71cd7f3..8c9bc4ea 100644
--- a/src/test/scala/chiselTests/Util.scala
+++ b/src/test/scala/chiselTests/Util.scala
@@ -5,6 +5,9 @@
 package chiselTests
 
 import chisel3._
+import chisel3.experimental.Interval
+import chisel3.internal.firrtl.{IntervalRange, KnownBinaryPoint, Width}
+import _root_.firrtl.{ir => firrtlir}
 
 class PassthroughModuleIO extends Bundle {
   val in = Input(UInt(32.W))
@@ -20,4 +23,53 @@ class PassthroughModule extends Module with AbstractPassthroughModule
 class PassthroughMultiIOModule extends MultiIOModule with AbstractPassthroughModule
 class PassthroughRawModule extends RawModule with AbstractPassthroughModule
 
+case class ScalaIntervalSimulator(intervalRange: IntervalRange) {
+  val binaryPoint: Int = intervalRange.binaryPoint.asInstanceOf[KnownBinaryPoint].value
+  val epsilon: Double = 1.0 / math.pow(2.0, binaryPoint.toDouble)
+
+  val (lower, upper) = (intervalRange.lowerBound, intervalRange.upperBound) match {
+
+    case (firrtlir.Closed(lower1), firrtlir.Closed(upper1)) => (lower1, upper1)
+    case (firrtlir.Closed(lower1), firrtlir.Open(upper1))   => (lower1, upper1 - epsilon)
+    case (firrtlir.Open(lower1),   firrtlir.Closed(upper1)) => (lower1 + epsilon, upper1)
+    case (firrtlir.Open(lower1),   firrtlir.Open(upper1))   => (lower1 + epsilon, upper1 - epsilon)
+    case _ =>
+      throw new Exception(s"lower and upper bounds must be defined, range here is $intervalRange")
+  }
+
+  def clip(value: BigDecimal): BigDecimal = {
+
+    if (value < lower) {
+      lower
+    }
+    else if (value > upper) {
+      upper
+    }
+    else {
+      value
+    }
+  }
+
+  def wrap(value: BigDecimal): BigDecimal = {
+
+    if (value < lower) {
+      upper + (value - lower) + epsilon
+    }
+    else if (value > upper) {
+      ((value - upper) - epsilon) + lower
+    }
+    else {
+      value
+    }
+  }
+
+  def allValues: Iterator[BigDecimal] = {
+    (lower to upper by epsilon).toIterator
+  }
+
+  def makeLit(value: BigDecimal): Interval = {
+    Interval.fromDouble(value.toDouble, width = Width(), binaryPoint = binaryPoint.BP)
+  }
+}
+