1. A method of performing a data expansion operation on a plurality of input data objects to generate expanded output data objects, the method comprising: receiving and decoding a data manipulation instruction defining a data expansion operation, a portion of the data manipulation instruction indicating an expansion operation from a number of predetermined types of data manipulation operations; responsive to the indication of an expansion operation generating one or more expansion objects, said one or more expansion objects being for use in extending an input data object; and manipulating said input data objects and said expansion objects according to control information programmed to produce a set of expanded output data objects.