Fine-grained application source code profiling for ASIP design

Current application specific instruction set processor (ASIP) design methodologies are mostly based on iterative architecture exploration that uses Architecture Description Languages (ADLs) and retargetable software development tools. However, for improved design efficiency, additional pre-architecture exploration tools are required to help narrow-down the huge design space and making coarse-grained instruction set architecture (ISA) decisions before detailed ADL modeling. Extensive application code profiling is the key in such early design stages. Based on a novel code instrumentation technology, we present a micro-profiling approach that fills the current gap between source-level and instruction-level profilers and combines their advantages w.r.t. speed and accuracy. We show how the micro-profiler is embedded into an advanced ASIP design flow and justify its use in a case study to design an MP3 decoder ASIP.