1. A method of processing data comprising: processing a function using a processor operable to perform a plurality of functions, said processor having interrupts enabled; receiving an interrupt at said processor; suspending processing of said function; accessing at least one control parameter, said at least one control parameter indicating whether processing of said function should be resumed from a point where it was interrupted or whether said function should be repeated following said interrupt; following completion of said interrupt continuing processing of said function either at a start of said function or at a point at which it was interrupted dependent upon said control parameter.