A device for writing data in a processor to memory at unaligned location. The data is stored in an internal register of the processor for writing to unaligned addresses of a memory partitioned by word boundaries into a plurality of words. A rotator is coupled to the internal register for rotating data of the internal register to a first position in accordance with written unaligned address. A store combine register is coupled to the rotator for temporarily storing data of the rotator. A mask selector is coupled to the rotator and the store combine register for selectively masking their data in accordance with the written unaligned address and storing the data masked to the memory.