This application is concerned with a device and method for fetching instructions from a data store for processing by a data processor. The device comprises: a register for storing an address of an instruction to be processed by said data processor; a fetch unit responsive to an address input to said fetch unit to fetch an instruction stored at said address; an adder for adding a predetermined amount to said address stored in said register prior to sending said address to said fetch unit, said predetermined amount determining a position in a program flow said fetched instruction has with respect to said instruction addressed in said register; said adder being responsive to detection of a change in program flow to reset said predetermined amount to an initial value, and to increase said predetermined amount for subsequent fetches by an amount equal to the separation between addresses such that consecutive addresses are fetched up to a maximum predetermined amount.