Strategies for Implementing a Multithreaded Shared Pipeline Processor

The management of parallelism, the simultaneous managementofmultiple environments, and the synchronization of cooperating threads are some of the fundamental issues that need to be solved inamultithreaded pipelined architecture. In this paper, we present several di erent solutions to these problems which are currently implemented in a cycle-accurate software simulator of a multithreaded architecture called the SAM architecture. The simulator is a software prototype of achip we expect to design and build within the coming year. The architecture contains two special instructions that allow parallelism to vary with time, and a two-level thread queue that allows the degree of parallelism to expand, theoretically, without limit, while still allowing for e cient dispatching of instructions. A concept called the short memory is introduced to support multiple environments. Because weintend to implement the SAM architecture as a real, functioning, general-purpose machine, we have also addressed such mundane issues as interrupts, traps, system calls, and process synchronization