US Patent 7533220 Microprocessor with improved data stream prefetching

A microprocessor coupled to a system memory has a memory subsystem with a translation look-aside buffer (TLB) for storing TLB information. The microprocessor also includes an instruction decode unit that decodes an instruction that specifies a data stream in the system memory and an abnormal TLB access policy. The microprocessor also includes a stream prefetch unit that generates a prefetch request to the memory subsystem to prefetch a cache line of the data stream from the system memory into the memory subsystem. If a virtual page address of the prefetch request causes an abnormal TLB access, the memory subsystem selectively aborts the prefetch request based on the abnormal TLB access policy specified in the instruction.