1 files changed, 28 insertions, 0 deletions
diff --git a/src/test/scala/ChiselTests/Pads.scala b/src/test/scala/ChiselTests/Pads.scala
new file mode 100644
index 00000000..a5c03d0b
--- /dev/null
+++ b/src/test/scala/ChiselTests/Pads.scala
@@ -0,0 +1,28 @@
+package ChiselTests
+import Chisel._
+
+class Pads extends Module {
+  val io = new Bundle {
+    val a   = Bits(INPUT,  4)
+    val asp = Bits(OUTPUT, 8)
+    val aup = Bits(OUTPUT, 8)
+  }
+  io.asp := io.a.toSInt
+  io.aup := io.a.toUInt
+}
+
+class PadsTester(c: Pads) extends Tester(c) {
+  def pads(x: BigInt, s: Int, w: Int) = {
+    val sign  = (x & (1 << (s-1)))
+    val wmask = (1 << w) - 1
+    val bmask = (1 << s) - 1
+    if (sign == 0) x else ((~bmask | x) & wmask)
+  }
+  for (t <- 0 until 16) {
+    val test_a = rnd.nextInt(1 << 4)
+    poke(c.io.a, test_a)
+    step(1)
+    expect(c.io.asp, pads(test_a, 4, 8))
+    expect(c.io.aup, test_a)
+  }
+}