The Instruction-Set extension problem: A survey

Over the last years, we have witnessed the increased use of Application-Specific Instruction-Set Processors (ASIPs). These ASIPs are processors that have a customizable histruction-set, which can be tuned towards specific requirements. The identification, definition and implementation of those operations that provide the largest performance improvement and that should be hardwired, extending in this way the Instruction-Set, constitutes a major challenge. The purpose of this paper is to investigate and study the issues regarding the customization of an Instruction-Set in function of the specific requirements of an application. Additionally, the paper provides an overview of all relevant aspects of the problem and compensates the lack of a general view of the problem in the existing literature.