riscv-boom
picorv32
Our great sponsors
riscv-boom | picorv32 | |
---|---|---|
12 | 15 | |
1,593 | 2,770 | |
3.0% | 2.8% | |
7.2 | 5.2 | |
about 1 month ago | about 1 month ago | |
Scala | Verilog | |
BSD 3-clause "New" or "Revised" License | ISC License |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
riscv-boom
- Is RISC-V ready for HPC? Evaluating the 64-core Sophon SG2042 RISC-V CPU
-
Cascade: CPU Fuzzing via Intricate Program Generation
Looks like from Appendix D that only 2 bugs were found in BOOM:
> 1. Inaccurate instruction count when minstret is written by software
I don't know what that means, but having minstret written by software was definitely not something I ever tested. In general, perf counters are likely to be undertested.
> 2. Static rounding is ignored for fdiv.s and fsqrt.s
A mistake was made in only listening to the dynamic rounding mode for the fdiv/sqrt unit. This is one of those bugs that is trivially found if you test for it, but it turns out that no benchmarking ever cared about this and from all of the fuzzers I used when I worked on BOOM, NONE of them hit it (including commercial ones...). Ooops.
Fixed here: https://github.com/riscv-boom/riscv-boom/pull/629/files
-
In your opinion, what is the most advanced open source softcore processor?
The two most micro architecturally advanced cores that I know of are BOOM, an out of order RV64GC core with all the features you expect plus sort of weird fancy things like short forward branch predication, and VROOM, another out of order RV64GC core with things like uop fusion and a trace cache.
-
PyXHDL - Python Frontend For VHDL And Verilog
it is used in the Berkley Out-of-Order RISC-V processor: https://github.com/riscv-boom/riscv-boom
- Semidynamics Unveils First Customizable RISC-V Cores for End Users
- TechTechPotato (Dr Ian Cutress): "Building High-Performance RISC-V Cores for Everything"
-
Open-source RISC-V CPU projects for contribution
SonicBOOM: https://github.com/riscv-boom/riscv-boom
-
The Surprising Subtleties of Zeroing a Register
Some cores are open source and you can see for yourself.
Rename logic from BOOM, a RISC-V core written in a DSL embedded in Scala:
https://github.com/riscv-boom/riscv-boom/blob/1ef2bc6f6c98e5...
From RSD, a core designed for FPGAs written in SystemVerilog:
https://github.com/rsd-devel/rsd/blob/master/Processor/Src/R...
And then there's the recently open-sourced XuanTie C910, which contains this Verilog… which is completely unreadable. Seems like it was produced by some kind of code generator that they didn't open-source?
https://github.com/T-head-Semi/openc910/blob/d4a3b947ec9bb8f...
-
Anandtech: "IBM Power10 Coming To Market: E1080 for 'Frictionless Hybrid Cloud Experiences'"
We don't have Sifive's specifically but we do have the open source cores they've historically used to design their cores: https://github.com/riscv-boom/riscv-boom https://github.com/chipsalliance/rocket-chip
-
Fence instruction implementation in BOOM
If you look at the decoder (https://github.com/riscv-boom/riscv-boom/blob/master/src/main/scala/exu/decode.scala), you can see that the fence instructions are also marked as "unique" instructions. Only one "unique" instruction is allowed in the pipeline at a time.
picorv32
-
SPI PROTOCOL in FPGA
In contrast to most people here saying you NEED to spend money. I disagree with that. You can implement and simulate a SPI master/slave fully on your computer, no FPGA or other hardware required. There are simulation models for SPI peripherals you could use. For example: https://github.com/YosysHQ/picorv32/blob/master/picosoc/spiflash.v
-
How many gates does a decent risc-v implementation take?
The Pico RV32 is pretty small, and can go as low as about 750 LUTs, with most features elided. I don't know how Xilinix LUTs translate to Lattice though.
-
Open-source RISC-V CPU projects for contribution
Picorv32: https://github.com/YosysHQ/picorv32
-
We ran a Unix-like OS (Xv6) on our home-built CPU with our home-built C compiler
There are loads of free RISC-V cores that you can read the source of and run on cheap FPGAs. Take a look at PicoRV32: https://github.com/YosysHQ/picorv32
-
SUGGEST AN OPEN SOURCE RISC-V CORE DESIGNED IN VERILOG
picorv32 is written in Verilog.
-
Minimax: a Compressed-First, Microcoded RISC-V CPU
In short: it works, though the implementation lacks the crystal clarity of FemtoRV32 and PicoRV32. The core is larger than SERV but has higher IPC and (very arguably) a more conventional implementation. The compressed instruction set is easier to expand into regular RV32I instructions than it is to execute directly.
-
Apple to Move a Part of Its Embedded Cores to RISC-V
That is, reducing the number of LUT required to implement a CPU of a given ISA.
A basic RV32 CPU is down to 500-700 LUT.
https://github.com/YosysHQ/picorv32
-
Designing a reasonable memory interface
I've bought a cheap FPGA board (Sipeed Tang Nano 9K) because I want to implement a little 8 or 16-bit CPU. The FPGA has plenty of BRAM for such a little CPU, so I wouldn't even need to implement an SPI controller initially, but I want to implement a von Neumann architecture, and was wondering if the only way of doing so using single port (or semi dual port) RAM would be to use 2 cycles or more for memory transfer operations (one for loading the instruction, one for executing the actual memory transfer), or if there was any technique that could be used to avoid this without having to implement instruction-level parallelism. Even if not, references to understandable code implementing a simple memory interface would be appreciated. I looked at PicoRV32 but couldn't really understand its inner workings.
-
Risc-v rv32i softcore processor for Zybo-z7-10
Have you looked at PicoRV32? https://github.com/YosysHQ/picorv32
-
Need help with implementing a media player using FPGAs ?
What I mean is that you use the FPGA fabric to implement a soft-core CPU, like MicroBlaze (Xilinx) or Nios II (Altera/Intel) or RISC-V or any other CPU you like. Then you can do the MP3 or WAV signal decoding in software, which will be orders of magnitude easier to do than to do it in hardware. For a media player, this is more than adequate.
What are some alternatives?
rocket-chip - Rocket Chip Generator
openlane - OpenLane is an automated RTL to GDSII flow based on several components including OpenROAD, Yosys, Magic, Netgen and custom methodology scripts for design exploration and optimization.
openc910 - OpenXuantie - OpenC910 Core
neorv32-setups - 📁 NEORV32 projects and exemplary setups for various FPGAs, boards and (open-source) toolchains.
XiangShan - Open-source high-performance RISC-V processor
rsd - RSD: RISC-V Out-of-Order Superscalar Processor
skywater-pdk - Open source process design kit for usage with SkyWater Technology Foundry's 130nm node.
riscv-mini - Simple RISC-V 3-stage Pipeline in Chisel
wd65c02 - Cycle accurate FPGA implementation of various 6502 CPU variants
Cores-VeeR-EL2 - VeeR EL2 Core
Projects - Ted Fried's MicroCore Labs Projects which include microsequencer-based FPGA cores and emulators for the 8088, 8086, 8051, 6502, 68000, Z80, Risc-V, and also Typewriter and EPROM Emulator projects. MCL51, MCL64, MCL65, MCL65+, MCL68, MCL86, MCL86+, MCL86jr, MCLR5, MCLZ8