add new APIs to BitPat (#2076)

* add Y and N to BitPat.

* add ## for BitPat.

* add rawString API.

* use rawString in decoder

* add select and slice to BitPat.

1 files changed, 23 insertions, 0 deletions

diff --git a/src/test/scala/chiselTests/util/BitPatSpec.scala b/src/test/scala/chiselTests/util/BitPatSpec.scala
index ca8dd85c..0c83493f 100644
--- a/src/test/scala/chiselTests/util/BitPatSpec.scala
+++ b/src/test/scala/chiselTests/util/BitPatSpec.scala
@@ -15,7 +15,30 @@ class BitPatSpec extends AnyFlatSpec with Matchers {
     BitPat("b" + testPattern).toString should be (s"BitPat($testPattern)")
   }
 
+  it should "convert a BitPat to raw form" in {
+    val testPattern = "0" * 32 + "1" * 32 + "?" * 32 + "?01" * 32
+    BitPat("b" + testPattern).rawString should be(testPattern)
+  }
+
   it should "not fail if BitPat width is 0" in {
     intercept[IllegalArgumentException]{BitPat("b")}
   }
+
+  it should "contact BitPat via ##" in {
+    (BitPat.Y(4) ## BitPat.dontCare(3) ## BitPat.N(2)).toString should be (s"BitPat(1111???00)")
+  }
+
+  it should "index and return new BitPat" in {
+    val b = BitPat("b1001???")
+    b(0) should be(BitPat.dontCare(1))
+    b(6) should be(BitPat.Y())
+    b(5) should be(BitPat.N())
+  }
+
+  it should "slice and return new BitPat" in {
+    val b = BitPat("b1001???")
+    b(2, 0) should be(BitPat("b???"))
+    b(4, 3) should be(BitPat("b01"))
+    b(6, 6) should be(BitPat("b1"))
+  }
 }