Make round method work properly with 0.BP

* Add checks with 0.BP to tests

Author: konda-x1

src/main/scala/fixedpoint/FixedPoint.scala

@@ -303,7 +303,7 @@ sealed class FixedPoint private[fixedpoint] (width: Width, private var _inferred
   def do_round(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): FixedPoint = {
     requireKnownBP()
     // Add 0.5 to the number and then floor it
-    (this + 0.5.F(binaryPoint)).floor
+    (this + 0.5.F(1.BP)).floor.setBinaryPoint(binaryPoint.get)
   }
 
   def do_===(that: FixedPoint)(implicit sourceInfo: SourceInfo, compileOptions: CompileOptions): Bool =
@@ -417,11 +417,9 @@ sealed class FixedPoint private[fixedpoint] (width: Width, private var _inferred
         val diff = that - current
         FixedPoint.fromData(
           that.BP,
-          (if (diff >= 0) {
-             data << diff
-           } else {
-             data >> -diff
-           }).asSInt,
+          (if (diff > 0) data << diff
+           else if (diff < 0) data >> -diff
+           else data).asSInt,
           Some(width + diff)
         )
       case UnknownBinaryPoint =>

src/test/scala/FixedPointSpec.scala

@@ -158,6 +158,7 @@ class FixedPointFloorTester extends BasicTester {
   assert(55.5.F(8.W, 2.BP).floor === 55.0.F(8.W, 2.BP))
   assert(-4.0.F(2.BP).floor === -4.0.F(2.BP))
   assert(0.125.F(8.W, 4.BP).floor === 0.0.F(8.W, 4.BP))
+  assert(3.0.F(0.BP).floor === 3.0.F(0.BP))
   stop()
 }
 
@@ -166,6 +167,7 @@ class FixedPointCeilTester extends BasicTester {
   assert(55.5.F(8.W, 2.BP).ceil === 56.0.F(8.W, 2.BP))
   assert(-4.0.F(2.BP).ceil === -4.0.F(2.BP))
   assert(0.125.F(8.W, 4.BP).ceil === 1.0.F(8.W, 4.BP))
+  assert(3.0.F(0.BP).ceil === 3.0.F(0.BP))
   stop()
 }
 
@@ -174,6 +176,7 @@ class FixedPointRoundTester extends BasicTester {
   assert(25.5.F(8.W, 2.BP).round === 26.0.F(8.W, 2.BP))
   assert(-4.0.F(2.BP).round === -4.0.F(2.BP))
   assert(0.125.F(8.W, 3.BP).round === 0.0.F(8.W, 3.BP))
+  assert(3.0.F(0.BP).round === 3.0.F(0.BP))
   stop()
 }