US Patent 11983537 Multi-threaded processor with power granularity and thread granularity

A multi-stage processor has a pre-fetch stage, and a sequence of pipelined processor stages. A thread map register contains thread identifiers, and a thread map valid register has locations corresponding to the thread map register and indicating whether a value in the thread map register is to be fetched or not, and a thread map length register indicates the number of thread map register locations forming a canonical sequence of thread identifiers to the pre-fetch stage. The pre-fetch stage does not act on a thread identifier with a not valid thread map valid value, thereby saving power in low demand conditions.