Make fromBits work with types other than UInt (#424)

* Make fromBits work with types other than UInt

* Oops, left in a println

* Add test for truncation/expansion

* Fix stuff that broke when FixedPoint fromBits PR was merged.

* Use .BP shorthand added in previous PR

5 files changed, 114 insertions, 25 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
index 26c971b3..559a55bc 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
@@ -21,6 +21,21 @@ sealed abstract class Aggregate extends Data {
     pushCommand(BulkConnect(sourceInfo, this.lref, that.lref))
 
   override def do_asUInt(implicit sourceInfo: SourceInfo): UInt = SeqUtils.do_asUInt(this.flatten)
+  def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
+    var i = 0
+    val wire = Wire(this.chiselCloneType)
+    val bits =
+      if (that.width.known && that.width.get >= wire.width.get) {
+        that
+      } else {
+        Wire(that.cloneTypeWidth(wire.width), init = that)
+      }
+    for (x <- wire.flatten) {
+      x := x.fromBits(bits(i + x.getWidth-1, i))
+      i += x.getWidth
+    }
+    wire.asInstanceOf[this.type]
+  }
 }
 
 object Vec {
diff --git a/chiselFrontend/src/main/scala/chisel3/core/Bits.scala b/chiselFrontend/src/main/scala/chisel3/core/Bits.scala
index c5fc10e7..e885f1ee 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Bits.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Bits.scala
@@ -292,12 +292,6 @@ sealed abstract class Bits(width: Width, override val litArg: Option[LitArg])
     pushOp(DefPrim(sourceInfo, UInt(w), ConcatOp, this.ref, that.ref))
   }
 
-  override def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
-    val res = Wire(this, null).asInstanceOf[this.type]
-    res := that
-    res
-  }
-
   /** Default print as [[Decimal]] */
   final def toPrintable: Printable = Decimal(this)
 }
@@ -519,6 +513,14 @@ sealed class UInt private[core] (width: Width, lit: Option[ULit] = None)
         throwException(s"cannot call $this.asFixedPoint(binaryPoint=$binaryPoint), you must specify a known binaryPoint")
     }
   }
+  def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
+    val res = Wire(this, null).asInstanceOf[this.type]
+    res := (that match {
+      case u: UInt => u
+      case _ => that.asUInt
+    })
+    res
+  }
 }
 
 // This is currently a factory because both Bits and UInt inherit it.
@@ -655,6 +657,14 @@ sealed class SInt private[core] (width: Width, lit: Option[SLit] = None)
         throwException(s"cannot call $this.asFixedPoint(binaryPoint=$binaryPoint), you must specify a known binaryPoint")
     }
   }
+  def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
+    val res = Wire(this, null).asInstanceOf[this.type]
+    res := (that match {
+      case s: SInt => s
+      case _ => that.asSInt
+    })
+    res
+  }
 }
 
 trait SIntFactory {
@@ -916,13 +926,15 @@ sealed class FixedPoint private (width: Width, val binaryPoint: BinaryPoint, lit
 
   override def do_asUInt(implicit sourceInfo: SourceInfo): UInt = pushOp(DefPrim(sourceInfo, UInt(this.width), AsUIntOp, ref))
   override def do_asSInt(implicit sourceInfo: SourceInfo): SInt = pushOp(DefPrim(sourceInfo, SInt(this.width), AsSIntOp, ref))
-  //TODO(chick): Consider "convert" as an arithmetic conversion to UInt/SInt
-
-  override def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
+  def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
     val res = Wire(this, null).asInstanceOf[this.type]
-    res := that.asFixedPoint(this.binaryPoint)
+    res := (that match {
+      case fp: FixedPoint => fp.asSInt.asFixedPoint(this.binaryPoint)
+      case _ => that.asFixedPoint(this.binaryPoint)
+    })
     res
   }
+  //TODO(chick): Consider "convert" as an arithmetic conversion to UInt/SInt
 }
 
 /** Use PrivateObject to force users to specify width and binaryPoint by name
diff --git a/chiselFrontend/src/main/scala/chisel3/core/Data.scala b/chiselFrontend/src/main/scala/chisel3/core/Data.scala
index 57ed0c59..6e80f045 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Data.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Data.scala
@@ -238,21 +238,7 @@ abstract class Data extends HasId {
     */
   def fromBits(that: Bits): this.type = macro CompileOptionsTransform.thatArg
 
-  def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
-    var i = 0
-    val wire = Wire(this.chiselCloneType)
-    val bits =
-      if (that.width.known && that.width.get >= wire.width.get) {
-        that
-      } else {
-        Wire(that.cloneTypeWidth(wire.width), init = that)
-      }
-    for (x <- wire.flatten) {
-      x := bits(i + x.getWidth-1, i)
-      i += x.getWidth
-    }
-    wire.asInstanceOf[this.type]
-  }
+  def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type
 
   /** Packs the value of this object as plain Bits.
     *
@@ -337,4 +323,9 @@ sealed class Clock extends Element(Width(1)) {
   def toPrintable: Printable = PString("CLOCK")
 
   override def do_asUInt(implicit sourceInfo: SourceInfo): UInt = pushOp(DefPrim(sourceInfo, UInt(this.width), AsUIntOp, ref))
+  override def do_fromBits(that: Bits)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): this.type = {
+    val ret = Wire(this.cloneType)
+    ret := that
+    ret.asInstanceOf[this.type]
+  }
 }
diff --git a/src/test/scala/chiselTests/FixedPointSpec.scala b/src/test/scala/chiselTests/FixedPointSpec.scala
index a08de073..4e6af33b 100644
--- a/src/test/scala/chiselTests/FixedPointSpec.scala
+++ b/src/test/scala/chiselTests/FixedPointSpec.scala
@@ -22,15 +22,19 @@ class FixedPointLiteralSpec extends FlatSpec with Matchers {
 class FixedPointFromBitsTester extends BasicTester {
     val uint = 3.U(4.W)
     val sint = -3.S
+    val fp   = FixedPoint.fromDouble(3.0, width = 4, binaryPoint = 0)
     val fp_tpe = FixedPoint(4.W, 1.BP)
     val uint_result = FixedPoint.fromDouble(1.5, width = 4, binaryPoint = 1)
     val sint_result = FixedPoint.fromDouble(-1.5, width = 4, binaryPoint = 1)
+    val fp_result   = FixedPoint.fromDouble(1.5, width = 4, binaryPoint = 1)
 
     val uint2fp = fp_tpe.fromBits(uint)
     val sint2fp = fp_tpe.fromBits(sint)
+    val fp2fp   = fp_tpe.fromBits(fp)
 
     assert(uint2fp === uint_result)
     assert(sint2fp === sint_result)
+    assert(fp2fp   === fp_result)
 
     stop()
 }
diff --git a/src/test/scala/chiselTests/FromBitsTester.scala b/src/test/scala/chiselTests/FromBitsTester.scala
new file mode 100644
index 00000000..5809b386
--- /dev/null
+++ b/src/test/scala/chiselTests/FromBitsTester.scala
@@ -0,0 +1,67 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import org.scalatest._
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
+import chisel3.core.DataMirror
+
+class FromBitsBundleTester extends BasicTester {
+  class MultiTypeBundle extends Bundle {
+    val u  = UInt(4.W)
+    val s  = SInt(4.W)
+    val fp = FixedPoint(4.W, 3.BP)
+  }
+
+  val bun = new MultiTypeBundle
+
+  val bunFromBits = bun.fromBits( ((4 << 8) + (15 << 4) + (12 << 0)).U )
+
+  assert(bunFromBits.u === 4.U)
+  assert(bunFromBits.s === -1.S)
+  assert(bunFromBits.fp === FixedPoint.fromDouble(-0.5, width=4, binaryPoint=3))
+
+  stop()
+}
+
+class FromBitsVecTester extends BasicTester {
+  val vec = Vec(4, SInt(4.W)).fromBits( ((15 << 12) + (0 << 8) + (1 << 4) + (2 << 0)).U )
+
+  assert(vec(0) === 2.S)
+  assert(vec(1) === 1.S)
+  assert(vec(2) === 0.S)
+  assert(vec(3) === -1.S)
+
+  stop()
+}
+
+class FromBitsTruncationTester extends BasicTester {
+  val truncate = UInt(3.W).fromBits( (64 + 3).U )
+  val expand   = UInt(3.W).fromBits( 1.U )
+
+  assert( DataMirror.widthOf(truncate).get == 3 )
+  assert( truncate === 3.U )
+  assert( DataMirror.widthOf(expand).get == 3 )
+  assert( expand === 1.U )
+
+  stop()
+}
+
+class FromBitsSpec extends ChiselFlatSpec {
+  behavior of "fromBits"
+
+  it should "work with Bundles containing Bits Types" in {
+    assertTesterPasses{ new FromBitsBundleTester }
+  }
+
+  it should "work with Vecs containing Bits Types" in {
+    assertTesterPasses{ new FromBitsVecTester }
+  }
+
+  it should "expand and truncate UInts of different width" in {
+    assertTesterPasses{ new FromBitsTruncationTester }
+  }
+}