1. A method comprising: operating a computer system in a first mode of speculative operation, said first mode permitting speculation of a first set of speculative operations; in response to an event during said operating, restoring a state of a microprocessor to a state stored prior to said event; and subsequent to said restoring, exiting said first mode and entering a partial speculation mode, wherein said partial speculation mode permits speculation of a second set of speculative operations comprising some but not all of said first set.