A two-level hybrid select logic for wide-issue superscalar processors

In a superscalar processor, select logic within the critical path of the instruction queue has become a performance bottleneck. This paper presents a high speed, two-level, hybrid select logic for wide-issue processors. The first level reduces delay by performing parallel age-based selection, and final arbitration is achieved in the second level with simple position-based select logic. The hybrid select logic circuits were implemented in dynamic logic on IBM 0.13mum technology. Simulation shows 36% reduction in delay with less than 1% IPC degradation compared to the conventional design