Instruction set selection for ASIP design

We describe an approach for application-specific processor design based on an extendible microprocessor core. Core-based design allows to derive application-specific instruction processors from a common base architecture with low non-recurring engineering cost. The results of this application-specific customization of a common base architecture are families of related and largely compatible processor families. These families can share support tools and even binary compatible code which has been written for the common base architecture. Critical code portions are customized using the application-specific instruction set extensions. We describe a hardware/software co-design methodology which can be used with this design approach. The presented approach uses the processor core to allow early evaluation of ASIP design options using rapid prototyping techniques. We demonstrate this approach with two case studies, based on the implementation and evaluation of application-specific processor extensions for Prolog program execution, and memory prefetching for vector and matrix operations