Application specific architectures: a recipe for fast, flexible and power efficient designs

The general purpose processor has long been the focus of intense optimization efforts that have resulted in an impressive doubling of performance every 18 months. However, recent evidence suggests that these efforts may be faltering as pipelining and ILP processing techniques experience diminishing returns. Application specific architectures hold great potential as an alternative means to continue scaling application performance. The approach works by specializing a design to a small domain of important applications, and it benefits from improved performance, greater power efficiency, and reduced area costs. This technique is well matched to embedded targets, where application domains are typically narrowIn this paper we present a case study of an application specific processor design. Our design, called the CryptoManiac processor, is an architecture specialized to efficiently execute cryptographic ciphers. We carefully highlight the domain specific application characteristics we identified and their accompanying optimizations in the CryptoManiac design. Detailed analyses of the design makes a strong case for application specific optimization. The CryptoManiac processor runs popular ciphers at twice the speed of a high-end general purpose processor, and the design renders nearly two orders-of-magnitude reduction in power consumption and area costs. Finally, we identify two key challenges that stand as barriers to wide spread adoption of application specific architectures.