Balancing structural hazards and hardware cost of pipelined processors

In this paper a tool to aid pipelined processor instruction set implementation is described. The purpose of the tool is to choose from among design alternatives a design that minimizes overall processor cost. In the proposed cost model, processor cost has two components, the cost of hardware necessary to realize the processor and the cost of degraded performance due to pipeline hazards as compared to an ideal pipelined processor. A previous paper detailed the optimization algorithm. This paper extends these results to handle enclosed pairs of instructions having structural hazards. The extended algorithm can produce an optimal result. This algorithm and several examples are presented