Storage Assignment to Decrease Code Size

DSP architectures typically provide indirect addressing modes with auto-increment and decrement. In addition, indexing mode is not available, and there are usually few, if any, general-purpose registers. Hence, it is necessary to use address registers and perform address arithmetic to access automatic variables. Subsuming the address arithmetic into auto-increment and auto-decrement modes improves the size of the generated code. In this paper we present a formulation of the problem of optimal storage assignment such that explicit instructions for address arithmetic are minimized. We prove that for the case of a single address register the decision problem is NP-complete. We then generalize the problem to multiple address registers. For both cases heuristic algorithms are given. Our experimental results indicate an improvement of 3% to 20% in code size.

• Type: Conference
• Year: 1995
• Where: PLDI
• Authors: Stan Y. Liao, Srinivas Devadas, Kurt Keutzer, Steven W. K. Tjiang, Albert Wang
• Keywords: Address Arithmetic, Address Registers, Multiple Address Registers, PLDI 1995, Programming Languages