1. A data register stage, comprising: a data storage circuit having a first latch and a second latch arranged in a master-slave flip-flop configuration for shifting in data serially from a serial input terminal and for shifting out data from a serial output terminal, the shifting operations being controlled by phase adjustable clock signals; and a status circuit for detecting opposite logic states stored in the first latch and the second latch, and for combining an output corresponding to the detected opposite logic states with a previous local status signal to provide a local status signal, the previous local status signal corresponding to detected opposite logic states stored in a previous data register stage.