Multithread execution mechanisms on RICA-1 for massively parallel computation

This paper presents a multithreaded processor architecture for massively parallel computers, and presents RICA-1 multithreaded processor based on it. RICA-1 provides fairly efficient mechanisms of message reception, thread invocation, message generation/transmission and synchronization. It provides simple communication pipelines. Computation pipelines and communication pipelines are highly fused within a processor architecture. Parallel primitives such as remote memory access, remote procedure call and synchronizations are efficiently performed by RICA-1. The first version of RICA-1 is being implemented by a CMOS standard cell chip with 200 K random gates and 13 KB internal RAMs. It is packed into the 527 pin CPGA package and will operate with a 50 MHz clock in August 1996. In RICA-1, communication pipelines and the RISC-type execution pipelines are highly fused by a simple sequencer and three sets of register files substantially reduces the thread switch overhead.