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

1 files changed, 67 insertions, 0 deletions

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 }
+  }
+}