Fix for ULong modulus operator

The division-by-2 to use signed primitives means that the remainder can
be 0<=x%y<2y instead of 0<=x%y<y. This change makes it behave the same
way as the division operator, handling the two cases where the top bit
(0x8000000000000000) is set separately and, if not, then adjusting the
calculated remainder to ensure it's in range. This relies upon the fact
that (x%2y)%y == (x%y).

src/main/scala/passera/unsigned/ULong.scala

@@ -93,46 +93,38 @@ case class ULong(override val longValue: Long) extends AnyVal with Unsigned[ULon
     val n = rep
     val d = x.rep
 
-    if (true) return {
-      if (d < 0) {
-        if (this < x)
-          ULong(0l)
-        else
-          ULong(1l)
-      }
-      else {
-        val q = ((n >>> 1) / d) << 1
-        val r = n - q * d
-        if (ULong(r) >= x)
-          ULong(q+1)
-        else
-          ULong(q)
-      }
+    if (d < 0) {
+      if (this < x)
+        ULong(0l)
+      else
+        ULong(1l)
+    } else {
+      val q = ((n >>> 1) / d) << 1
+      val r = n - q * d
+      if (ULong(r) >= x)
+        ULong(q+1)
+      else
+        ULong(q)
     }
-
-    val t = d >> 63
-    val n1 = n & ~t
-    val a = n1 >>> 1
-    val b = a / d
-    val q0 = b << 1
-    val r = n - q0 * d
-    val q = q0 + (if (ULong(r) >= x) 1l else 0l)
-    ULong(q.toLong)
   }
 
   def %(x: ULong): ULong = {
     val n = rep
     val d = x.rep
 
-
-    val t = d >> 63
-    val n1 = n & ~t
-    val a = n1 >>> 1
-    val b = a / d
-    val q0 = b << 1
-    val r = n - q0 * d
-    // val q = q0 + (if (ULong(r) >= ULong(d)) 1 else 0)
-    ULong(r.toLong)
+    if (d < 0) {
+      if (this < x)
+        ULong(n)
+      else
+        ULong(n - d)
+    } else {
+      val q = ((n >>> 1) / d) << 1
+      val r = n - q * d
+      if (ULong(r) >= x)
+        ULong(r - d)
+      else
+        ULong(r)
+    }
   }
 
   override def toString =