These meetings provide an opportunity to share the latest ideas around open source in the RISC-V ecosystem, combined with plenty of time for networking.

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Synopsis

Our quarterly meetup for the London open source community, focusing on RISC-V and open source, hosted by the BCS Open Source Specialist Group and the UK Open Source Hardware User Group.

Evaluating the proposed Zce extension

RISC-V is an open source fast growing ISA designed at the University of California, Berkeley. The ISA was designed to target various wide range of applications starting from HPC to Embedded Systems. For RISC-V to be competitive in embedded space, its code size density has to be at least on par or better than commercial alternatives.

While RISC-V contains several features like variable instruction length and compressed instruction that should help achieving that. Several benchmarks [1] indicate that RISC-V code density is worse than that of these alternatives. Luckily, RISC-V was designed to accommodate for extensions to enhance various aspects of its performance.

One of those extensions is Zce, this extension purpose is to help close the gap of code density with these alternatives. In this presentation, I will present the evaluation criteria used for comparison, review the main contributing factors to the worse code density performance, review the main Zce instructions for better code density (PushPop, TBLJAL and Multimove), and present their approximate savings.

References
[1] Perotti, Matteo, et al. “HW/SW approaches for RISC-V code size reduction.” Workshop on Computer Architecture Research with RISC-V (CARRV 2020)

The LLVM inliner and MI: Mutual Inlining

Nidal will be presenting the work done by Western Digital on the LLVM inliner and the solutions we are exploring to improve it.

RISC-V Online Tutor

RISC-V Online Tutor provides structured, self-paced RISC-V architecture and applications training and reference. It uses the vicilogic platform (online learning, remote FPGA prototyping and course builder). The course browser transparently interacts with remote RISC-V FPGA hardware. Lessons control remote hardware input signals, probe internal RISC-V signals, and overlay signal state as widgets on interactive course diagrams. The strategy provides a visually-rich, interactive learn-by-doing experience.

Users learn RISC-V assembly, architecture design, RISC-V code HDL capture, pipelining and hazards, and introductory-level C to assembly. The platform can be used to extend training modules to support RISC-V training, e.g, on RISC-V extension hardware implementation.

The presentation describes the course structure, pedagogy examples, course build process, recent user experience, and analytics.

About the speakers

Ibrahim Abu Kharmeh, Huawei Bristol, UK

Ibrahim has recently completed an Electronic Engineering MSc (Micro Electronics Stream) at the University of Southampton. During his masters degree, he researched the feasibility of implementing a NISC based processor for signal processing. He is currently working for Huawei Bristol where he is researching, modelling and benchmarking code size optimization for the RISC-V extension Zce. Previously, he worked as an embedded HW/SW design engineer for just over 2 years.

Nidal Faour, Western Digital Corporation, Israel

Nidal Faour is a toolchain Engineer at Western Digital CTO group. Nidal started at Western Digital 10 years ago. After 5 years of experience in Embedded systems as a FW engineer, then over 4 years of experience in build systems he joined the CTO team, where he started working on the RISC-V toolchain and doing research on RISC-V code size and footprint for embedded systems.

Fearghal Morgan, NUI Galway, Ireland

Fearghal Morgan is a lecturer/researcher in the National University of Ireland, Galway (NUI Galway), working in online learning and remote labs, reconfigurable computing and bio-inspired systems. Fearghal has worked in industry (ASIC and Comms design), along with 28 years in University teaching and research.

Our events are for adults aged 16 years and over.

This event is brought to you by: BCS Open Source specialist group

Webinar: London Open Source Meetup for RISC-V
Date and time
19 April, 6:00pm - 8:30pm
Location
Webinar
Price
Free