Add LSBOr and MSBOr utility

integration-tests/src/test/scala/chiselTests/util/experimental/algorithm/Bitwise.scala

@@ -0,0 +1,45 @@
+import chisel3._
+import chisel3.util._
+import chisel3.experimental.util.algorithm._
+import chiseltest._
+import chiseltest.formal._
+import org.scalatest.flatspec.AnyFlatSpec
+
+class LSBOrTestModule(width: Int) extends Module {
+  val input = IO(Input(UInt(width.W)))
+
+  var lsb = false.B
+  val vec = for(b <- input.asBools) yield {
+    val cur = b || lsb
+    lsb = cur
+    cur
+  }
+  val ref = VecInit(vec).asUInt
+
+  val testee = LSBOr(input)
+
+  assert(testee === ref)
+}
+
+class MSBOrTestModule(width: Int) extends Module {
+  val input = IO(Input(UInt(width.W)))
+
+  val ref = Reverse(LSBOr(Reverse(input)))
+  val testee = MSBOr(input)
+
+  assert(testee === ref)
+}
+
+class LSBMSBOrTest extends AnyFlatSpec with ChiselScalatestTester with Formal {
+  "LSBOr" should "correctly computes" in {
+    for(i <- 1 to 16) {
+      verify(new LSBOrTestModule(i), Seq(BoundedCheck(1)))
+    }
+  }
+
+  "MSBOr" should "correctly computes" in {
+    for(i <- 1 to 16) {
+      verify(new MSBOrTestModule(i), Seq(BoundedCheck(1)))
+    }
+  }
+}

src/main/scala/chisel3/experimental/util/algorithm/Bitwise.scala

@@ -0,0 +1,29 @@
+package chisel3.experimental.util.algorithm
+
+import chisel3._
+
+/** Map each bits to logical or of itself and all bits less siginificant than it.
+  * @example {{{
+  * LSBOr("b00001000".U) // Returns "b11111000".U
+  * LSBOr("b00010100".U) // Returns "b11111100".U
+  * LSBOr("b00000000".U) // Returns "b00000000".U
+  * }}}
+  */
+object LSBOr {
+  def apply(data: UInt): UInt = VecInit(Seq.tabulate(data.getWidth) { i: Int =>
+    VecInit(data.asBools().dropRight(data.getWidth - i - 1)).asUInt().orR()
+  }).asUInt()
+}
+
+/** Map each bits to logical or of itself and all bits more siginificant than it.
+  * @example {{{
+  * MSBOr("b00001000".U) // Returns "b00001111".U
+  * MSBOr("b00010100".U) // Returns "b00011111".U
+  * MSBOr("b00000000".U) // Returns "b00000000".U
+  * }}}
+  */
+object MSBOr {
+  def apply(data: UInt): UInt = VecInit(Seq.tabulate(data.getWidth) { i: Int =>
+    VecInit(data.asBools().drop(i)).asUInt().orR()
+  }).asUInt()
+}