An Adjustable Heuristic for Offset Assignment Problems in Embedded System Design

Offset assignment (OA) is a highly effective address code optimization technique for embedded processors with limited memory. Modify registers (MRs) concern the offset difference of address code for offset assignment (OA) problems. Address registers (ARs) concern the assignment of program variables for general offset assignment (GOA) problems. This paper proposes a novel MRs and ARs assignment technique for SOA and GOA problems based on specialized DSPs Address Generation Units (AGU) machines. A technique to reduce the number of distinct offset difference so as to reduce the modify register assignment instructions was proposed for SOA and during GOA such that the cost is further reduced. An adjustable ARs assignment technique was proposed to reduce the GOA cost and the number of distinct offset difference during GOA. Our experiments show the reduction of the number of distinct offset difference during GOA can also help to improve the GOA cost.