Partitioning prefetch registers to prevent at least in part inconsistent prefetch information from being stored in a prefetch register of a multithreading processor

A method and multithreaded processor for dynamically reallocating prefetch registers upon the processor switching modes of operation. An execution unit may be coupled to a prefetch engine where the execution unit may be configured to receive prefetch instructions regarding prefetching data. The prefetch engine may comprise a plurality of prefetch registers. The execution unit may further be configured to load the plurality of prefetch registers with information regarding prefetching data obtained from the prefetch instructions. In a single thread mode of operation, the plurality of prefetch registers are allocated to be accessed by either a first or a second thread. In a multithread mode of operation, the plurality of prefetch registers are allocated to be accessed among the first and second threads.