A SIMD operation optimization algorithm in HW/SW partitioning for SIMD processor cores

摘要

A SIMD operation is composed of an arithmetic operation, a shift operation, and a saturation operation. They are called suboperations. By executing all the suboperations in a SIMD operation in one clock cycle, we can execute an application in a short time, but its corresponding functional unit in a processor core needs a complex configuration. By assigning all suboperations to their respective functional unit, we can simplify a configuration of a SIMD functional unit, but it takes much execution time. This paper proposes a SIMD operation optimization algorithm in HW/SW partitioning for SIMD processor cores. Given an application program and a timing constraint, we assume an initial processor core which executes all the suboperations in each SIMD operation in one clock cycle. Then, the algorithm divides a complex SIMD operation into two arithmetic operations with the bit extending operation and one bit extracting operation with the shift operation one by one. By repeating this process while a timing constraint is satisfied, a total cost of a processor core can be reduced. The experimental results show effectiveness of the algorithm.