Hexagon DSP: An Architecture Optimized for Mobile Multimedia and Communications

Heterogeneous computing is essential for mobile products to meet power and performance targets. The Qualcomm Hexagon DSP, now in its fifth generation, is used for both modem processing and multimedia acceleration. By offloading multimedia tasks such as voice, audio, sensor, and image processing from the CPU to the DSP, Hexagon achieves significant power savings. Hexagon features a unique architecture that combines application-specific instructions, a VLIW instruction set architecture, and hardware multithreading. The design approach is to maximize work per cycle for performance, but run at modest clock speeds and focus the implementation on low power. This article provides an overview of the Hexagon architecture. The processor is designed to deliver far superior energy efficiency compared to mobile CPU alternatives and thereby help achieve long battery life for important mobile applications.