AxHLS: Design Space Exploration and High-Level Synthesis of Approximate Accelerators using Approximate Functional Units and Analytical Models

Jorge Castro-Godinez, Julian Mateus-Vargas, Muhammad Shafique, Jorg Henkel

Research output: Contribution to journalConference articlepeer-review


With the emergence of approximate computing as a design paradigm, many approximate functional units have been proposed, particularly approximate adders and multipliers. These circuits compromise the accuracy of their results within a tolerable limit to reduce the required computational effort and energy requirements. However, for an ongoing number of such approximate circuits reported in the literature, selecting those that minimize the required resources for designing and generating an approximate accelerator from a high-level specification, while satisfying a defined accuracy constraint, is a joint high-level synthesis (HLS) and design space exploration (DSE) challenge. In this paper, we propose a novel automated framework for HLS of approximate accelerators using a given library of approximate functional units. Since repetitive circuit synthesis and gate-level simulations require a significant amount of time, to enable our framework, we present AxME, a set of analytical models for estimating the required computational resources when using approximate adders and multipliers in approximate designs. We propose DSEwam, a DSE methodology for error-tolerant applications, in which analytical models, such as AxME, are used to estimate resources needed and the accuracy of approximate designs. Furthermore, we integrate DSEwam into an HLS tool to automatically generate Pareto-optimal, or near Pareto-optimal, approximate accelerators from C language descriptions, for a given error threshold and minimization goal. We release our DSE framework as an open-source contribution, which will significantly boost the research and development in the field of automatic generation of approximate accelerators.

Original languageEnglish (US)
Article number9256645
JournalIEEE/ACM International Conference on Computer-Aided Design, Digest of Technical Papers, ICCAD
StatePublished - Nov 2 2020
Event39th IEEE/ACM International Conference on Computer-Aided Design, ICCAD 2020 - Virtual, San Diego, United States
Duration: Nov 2 2020Nov 5 2020


  • analytical models
  • Approximate computing
  • design automation
  • design-space exploration
  • high-level synthesis

ASJC Scopus subject areas

  • Software
  • Computer Science Applications
  • Computer Graphics and Computer-Aided Design


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