A method and a programmable unit for bit field shifting in a memory device in a programmable unit as a result of the execution of an instruction, in which a bit segment is shifted within a first memory unit to a second memory unit, are presented. The bit segment is read with a first bit length from a first bit field in the first memory unit starting at a first start point. The bit segment that has been read is stored in the first bit field in the second memory unit starting at a second start point. The first or the second start points is updated by a predetermined value and the updated start point is stored for subsequent method steps.