Optimizing address assignment for scheduling embedded DSPs

DSP architecture typically provides indirect addressing modes with auto-increment and auto-decrement. Subsuming the address arithmetic into auto-increment and auto-decrement modes improves the size and performance of generated code. A lot of previous work has been done on address assignment optimization to achieve code size reduction by minimizing address operations for single functional unit processors. However, minimizing address operations alone may not directly reduce code size and schedule length for multiple-functional-unit processors. In this paper, we exploit address assignment and scheduling for multiple functional units processors. Our approach is to first construct a nice address assignment and then do scheduling. By fully taking advantage of the address assignment during scheduling, code size and schedule length can be significantly reduced. We propose a multiple-functional-unit algorithm to do both address assignment and scheduling. The experimental results show that our algorithm can greatly reduce code size and schedule length compared to the previous work.