make groups only update update-causing ports

sim/port.lua

@@ -45,19 +45,15 @@ function Port.new(self, type, direction, position, causeupdate, sim)
 	return o
 end
 
-function Port.setstate(port, state)
+function Port.setstate(port, state) -- output state
 	if state ~= port.state then
 		port.state = state
-		Simulation.queuegroup(Port.getsim(port), port.group)
-	end
-end
-
-function Port.setinputstate(port, state)
-	if state ~= port.state then
-		port.state = state
-		if port.causeupdate then
-			Simulation.queuegate(Port.getsim(port), port.gate)
+		if state then
+			Port.getgroup(port).state_num = Port.getgroup(port).state_num + 1
+		else
+			Port.getgroup(port).state_num = Port.getgroup(port).state_num - 1
 		end
+		Simulation.queuegroup(Port.getsim(port), Port.getgroup(port))
 	end
 end
 
@@ -80,6 +76,10 @@ function Port.isfalling(port)
 	return port.group.state == false and (port.updatetick == Port.getsim(port).currenttick)
 end
 
+function Port.getgate(port)
+	return port.gate
+end
+
 function Port.setgate(port, gate)
 	port.gate = gate
 end
@@ -100,6 +100,10 @@ function Port.getstate(port)
 	return port.state
 end
 
+function Port.getinputstate(port)
+	return Port.getgroup(port).state
+end
+
 function Port.getsim(port)
 	return port.sim
 end