CoreVA: A Configurable Resource-Efficient VLIW Processor Architecture

Abstract

Mobile signal processing applications have a limited energy budget and require resource-efficient processing elements. General purpose VLIW CPUs offer a high energy efficiency and allow for the execution of a wide range of applications in this domain. In this work we present the configurable 32 bit VLIW processor architecture CoreVA. Besides the number of issue slots, it allows for a fine-grained configuration of the amount and characteristics of the processor's functional units (e.g., ALUs, MACs, or LD/ST units). A design-space exploration is performed to evaluate how these functional units impact area and power consumption. The basic configuration with one ALU, MAC, DIV, and LD/ST unit has a power consumption of 11.796 mW and an area of 0.142 mm2 at a clock frequency of 750 MHz in a 28 nm FD-SOI process. The maximum clock frequency in this process node is 833 MHz. To bear a relation of the hardware requirements to possible performance gains of the application, a signal processing algorithm is used as a benchmark to evaluate the energy consumption of different hardware configurations. The lowest energy consumption is observed with a configuration of 4 issue slots using 4 ALUs, 4 MACs, and 2 LD/ST units. This is an improvement by a factor of 1.68 compared to the single issue slot configuration.