Simon Bjurek
--- a/b_asic/scheduler_gui/scheduler_item.py
+++ b/b_asic/scheduler_gui/scheduler_item.py
        op_start_time = self.schedule.start_time_of_operation(item.graph_id)
        new_start_time = floor(pos) - floor(self._x_axis_indent)
        move_time = new_start_time - op_start_time
-        op = self._schedule.sfg.find_by_id(item.graph_id)
+        op = self._schedule._sfg.find_by_id(item.graph_id)
--- a/b_asic/schedule.py
+++ b/b_asic/schedule.py
                source_port_start_time + source_port_latency_offset
                > self._schedule_time
            ):
-                lap += (
-                    source_port_start_time + source_port_latency_offset
-                ) // self._schedule_time
+                lap += 1
--- a/b_asic/schedule.py
+++ b/b_asic/schedule.py
-            for signal, signal_slack in signal_slacks.items():
-                new_slack = signal_slack
-                laps = 0
-                while new_slack < 0:
-                    laps += 1
-                    new_slack += self._schedule_time
-                self._laps[signal.graph_id] = laps
+        # update input laps
+        for input_port in op.inputs:
+            laps = 0
+            if self._schedule_time is not None:
+                current_lap = time // self._schedule_time
+                source_port = source_op = input_port.signals[0].source
+                source_op = source_port.operation
+
+                if not isinstance(source_op, Delay) and not isinstance(
-                if not isinstance(source_op, Delay) and not isinstance(
+                if not isinstance(source_op, (Delay, DontCare)):