VIRTUAL FUNCTIONAL UNITS FOR VLIW PROCESSORS

摘要

A virtual functional unit design is presented that is employed in a statically scheduled VLIW processor. "Virtual" views of the function unit appear to the processor scheduler that exceed the number of physical instantiations of the functional unit. As a result, significant processor performance improvements can be achieved for those types of functional units that are too difficult or too costly to physically duplicate. By providing different virtual views to the different clusters of a VLIW processor, the compiler/scheduler can generate more efficient code for the processor, than a processor without virtual views and the physical unit restricted to a subset of the processor's clusters. The compiler/scheduler guarantees that the restrictions with respect to scheduling of operations for functional units with multiple virtual views is met. NON-clustered processors also benefit from virtual views. By providing multiple virtual views in multiple issue slots of a physical function unit, the compiler/scheduler has more freedom to schedule operations for the functional unit.