TVLSI-00611-2007: Special Section on Application-Specific Processors 1 Abstract—State-of-the-art ASIPs (Application Specific

Instruction set Processors) allow the designer to define individual pre-fabrication customizations, thus improving the degree of specialization towards the actual application requirements, e.g. the computational hot spots. However, only a subset of hot spots can be targeted to keep the ASIP within a reasonable size. We propose a modular Special Instruction composition with multiple implementation pos-sibilities per Special Instruction, compile-time embedded instructions to trigger a run-time adaptation of the In-struction Set, and a run-time system that dynamically se-lects an appropriate variation of the Instruction Set, i.e. a situation-dependent beneficial implementation for each Special Instruction. We thereby achieve an up to 3.0x (avg. 1.4x) better efficiency of resource usage compared to cur-rent state-of-the-art ASIPs resulting in a 3.1x (avg. 1.4x) improved application performance (compared to a GPP up to 25.7x and avg. 17.6x)