Kentaro Shimada

A superscalar RISC processor with 160 FPRs for large scale scientific processing

We have developed a superscalar RISC processor for the super technical server HITACHI SR8000. The processor includes architectural features specialized in scientific applications, in which massive amounts of data in the main memory must be processed. These features are a slide-windowed-registers scheme and a simultaneous execution of up to 16 prefetch instructions. The slide-windowed-registers scheme enables instructions of the processor to access any of 160 floating point registers (FPRs). The execution mechanism for prefetch instructions produces high efficiency of the out-of-order superscalar processor despite the long latency of the main memory. A logic simulation showed that the performance of the processor reaches over 3 floating-point operations per cycle and the memory throughput of over 12 bytes per cycle.