The lowRISC blog

Barcelona RISC-V Workshop: Day One

The eighth RISC-V workshop is going on today in Barcleona. As usual, I’ll be keeping a semi-live blog of talks and announcements throughout the day. Follow here for the day two live blog. Note that slides from most presentations are now available at riscv.org. Introduction: Rick O’Connor This workshop has 325 attendees representing 101 companies and 25 universties. Largest outside of Silicon Valley. Rick gives the usual overview of the RISC-V Foundation structure.

Read More…

lowRISC 0-5 milestone release

The lowRISC 0.5 milestone release is now available. The various changes are best described in our accompanying documentation, but the main focus is the integration of open-source Ethernet IP. The tutorial demonstrates how to use Ethernet support to boot with an NFS root, as well as with a rootfs on SD card. Our main development focus currently is migrating to a newer version of the upstream Rocket chip design and reintegrating our changes on top of that, but we felt that the integration of Ethernet support merits a release before that change.

Read More…

Seventh RISC-V Workshop: Day Two

The seventh RISC-V workshop is concluding today at Western Digital in Milpitas. I’ll be keeping a semi-live blog of talks and announcements throughout the day. Celerity: An Open Source 511-core RISC-V Tiered Accelerator Fabric: Michael Taylor Built in only 9 months. Celerity is an accelerator-centric SoC with a tiered accelertor fabric. Implemented in TSMC 16nm FFC. 25mm2 die area, 385M transistors Why 511 RISC-V cores? 5 Linux-capable RV64G Rocket cores, 496-core RV32IM mesh tiled area “manycore”, 10-core RV32IM mesh tiled array (low voltage).

Read More…

Seventh RISC-V Workshop: Day One

The seventh RISC-V workshop is going on today and tomorrow at Western Digital in Milpitas. I’ll be keeping a semi-live blog of talks and announcements throughout the day. Follow here for the day two live blog. Introduction: Rick O’Connor Workshop is sold out, 498 attendees registered representing 138 companies and 35 universities. There will be 47 sessions squeezed into 12 and 24 minute increments, plus 26 poster / demo sessions.

Read More…

GSoC 2017 student report: core lockstep for minion cores

This year, as part of Google Summer of Code we had the pleasure of working with Nikitas Chronas. Alongside his degree studies, Nikitas had become involved with the Libre Space Foundation and developed a strong interest in the possibility of open source hardware in CubeSats. Fault tolerance of some sort is important for harsh environments, and Nikitas worked to add fault tolerance through the implementation of core lockstep for the PULPino-based minion core subsystem.

Read More…

Moving RISC-V LLVM forwards

A high quality, upstream RISC-V backend for LLVM is perhaps the most frequently requested missing piece of the RISC-V software ecosystem. This blog post provides an update on the rapid progress we’ve been making towards that goal, outlines next steps and upcoming events, and tries to better explain the approach that we’re taking. As always, you can track status here and find the code here. Status I’ve been able to make substantial progress since the last update.

Read More…

lowRISC tagged memory OS enablement

This summer, we were fortunate enough to have Katherine Lim join the lowRISC team at the University of Cambridge Computer Laboratory as an intern. Katherine’s focus was on operating system and software enabled for lowRISC’s tagged memory, building upon our most recent milestone release. As Katherine’s detailed write-up demonstrates, it’s been a very productive summer. The goal of this internship was to take the lowRISC hardware release, and demonstrate kernel support and software support for the hardware tagged memory primitives.

Read More…

We're hiring! Work on making open source hardware a reality

We are looking for a talented hardware engineer to join the lowRISC team and help make our vision for an open source, secure, and flexible SoC a reality. Apply now! lowRISC C.I.C. is a not-for-profit company that aims to demonstrate, promote and support the use of open-source hardware. The lowRISC project was established in 2014 with the aim of bringing the benefits of open-source to the hardware world. It is working to do this by producing a high quality, secure, open, and flexible System-on-Chip (SoC) platform.

Read More…

Building upstream RISC-V GCC+binutils+newlib: the quick and dirty way

There are a number of available options for building a RISC-V GCC toolchain. You might use the build system from the riscv/riscv-tools repository, or investigate toolchain generators such as crosstool-ng. However in the case of riscv-tools, it’s not always clear how this corresponds to the code in the relevant upstream projects. When investigating a potential bug, you often just want to build the latest upstream code with as little fuss as possible.

Read More…

lowRISC 0-4 milestone release

The lowRISC 0.4 milestone release is now available. The various changes are best described in our accompanying documentation, but in summary this release: Moves forward our support for tagged memory by re-integrating the tag cache, reducing overhead with a hierarchical scheme. This will significantly reduce caches misses caused by tagged memory accesses where tags are distributed sparsely. Integrates support for specifying and configuring tag propagation and exception behaviour. A PULPino based “minion core” has been integrated, and is used to provide peripherals such as the SD card interface, keyboard, and VGA tex display (when using the Nexys4 DDR FPGA development board).

Read More…