Publications de Grace Zgheib | EPFL Graph Search

Detailed Placement for Dedicated LUT-Level FPGA Interconnect

Paolo Ienne, Grace Zgheib, Stefan Nikolic

In this work, we develop timing-driven CAD support for FPGA architectures with direct connections between LUTs. We do so by proposing an efficient ILP-based detailed placer, which moves a carefully selected subset of LUTs from their original positions, so ...

ASSOC COMPUTING MACHINERY2022

Straight to the Point: Intra- and Intercluster LUT Connections to Mitigate the Delay of Programmable Routing

Paolo Ienne, Grace Zgheib, Stefan Nikolic

Technology scaling makes metal delay ever more problematic, but routing between Look-Up Tables (LUTs) still passes through a series of transistors. It seems wise to avoid the corresponding delay whenever possible. Direct connections between LUTs, both with ...

ASSOC COMPUTING MACHINERY2020

Timing-Driven Placement for FPGA Architectures with Dedicated Routing Paths

Paolo Ienne, Grace Zgheib, Stefan Nikolic

The idea of introducing dedicated, fast paths between certain FPGA elements in order to reduce delay is neither new nor particularly hard to come up with. What is less obvious, however, is how to put such paths to actual use. In this work, we propose an ef ...

IEEE2020

Finding a Needle in the Haystack of Hardened Interconnect Patterns

Paolo Ienne, Grace Zgheib, Stefan Nikolic

Circuits naturally exhibit recurring patterns of local interconnect. Hardening those patterns when designing Field Programmable Gate Array (FPGA) clusters can both eliminate slow programmable connections from the critical path and remove the need for trans ...

IEEE2019

NAND-NOR: A Compact, Fast, and Delay Balanced FPGA Logic Element

Paolo Ienne, Yu Lin, Grace Zgheib, Wei Li

The And-Inverter Cone has been introduced as an alternative logic element to the look-up table in FPGAs, since it improves their performance and resource utilization. However, further analysis of the AIC design showed that it suffers from the delay discrep ...

ACM2017

Evaluating FPGA clusters under wide ranges of design parameters

Paolo Ienne, Grace Zgheib

2017

Leading the Blind : Automated Transistor-Level Modeling for FPGA Architects

Grace Zgheib

The design and development of innovative FPGA architectures hinge on the flexibility of its toolchain. Retargetable toolchains, like the Verilog-to-Routing (VTR) flow, have been developed to enable the testing of new FPGAs by mapping circuits onto easily-d ...

EPFL2017

Improving Circuit Mapping Performance Through MIG-based Synthesis for Carry Chains

Paolo Ienne, Giovanni De Micheli, Ana Petkovska, Grace Zgheib, Luca Gaetano Amarù, Xifan Tang, Pierre-Emmanuel Julien Marc Gaillardon, Mathias Soeken, Zhufei Chu

Hard-wired carry chains in FPGAs are designed to improve efficiency of important arithmetic primitives. Although they are proven to be effective for arithmetic-rich functions, there are very few studies on the optimization opportunities of carry chains for ...

ACM2017

Automatic wire modeling to explore novel FPGA architectures

Paolo Ienne, Grace Zgheib

2016

FPRESSO: Enabling Express Transistor-Level Exploration of FPGA Architectures

Paolo Ienne, David Novo Bruna, Grace Zgheib, Manana Lortkipanidze

2016

A technology mapper for depth-constrained FPGA logic cells

Paolo Ienne, David Novo Bruna, Grace Zgheib

2015

Improved carry chain mapping for the VTR flow

Paolo Ienne, Ana Petkovska, David Novo Bruna, Grace Zgheib

Carry chains facilitate the implementation of adders and improve the performance of arithmetic circuits in FPGAs. The last version of the commonly used open-source Verilog-to-Routing (VTR) CAD flow now enables modelling carry chains in FPGA architectures. ...

IEEE2015

Non-LUT field-programmable gate arrays

Paolo Ienne, Hadi Parandeh Afshar, David Novo Bruna, Grace Zgheib

New logic blocks capable of replacing the use of Look-Up Tables (LUTs) in integrated circuits, such as Field-Programmable Gate Arrays (FPGAs), are disclosed herein. In one embodiment, the new logic block is a tree structure comprised of a number of levels ...

2014