A Delay-Driven Iterative Technology Mapping Framework

Abstract

Technology mapping is the pivotal synthesis step that translates abstract logical models into technology-dependent implementations using the designated library, e.g., standard cells for ASICs. The efficient solutions heavily rely on the gate selection guided by estimated delay. However, estimating these delays is sophisticated due to the absence of actual interconnect load and transition time during the mapping. In this article, we revisit the difficulties of the delay-driven mapping problem and explore three key insights to address these. Inspired by the insights, we first design a structure-aware load-slew model that integrates input transitions and output loads for gate delay estimations. Benefiting from the model, we propose a delay-iterative framework that progressively reduces the overall circuit delay by further aligning library characteristics with logical network structures. Finally, experiments with 130 nm and 7 nm libraries show its superiority, which averagely reduces circuit delay by 10% with nonlinear delay model, and 6% in delay after P&R, as compared to ABC.