XiangShan
XiangShan (香山) is an open-source high-performance RISC-V processor project.
中文说明在此。
Copyright 2020-2021 by Institute of Computing Technology, Chinese Academy of Sciences.
Docs and slides
We gave 20+ presentations on RISC-V World Conference China 2021. XiangShan tutorial was held at the same place. Our slides for RVWC2021 have been updated on our doc repo (in Chinese).
我们在2021年RISC-V**峰会的报告已经更新到这里。未来的文档和相关信息也将更新到相同的仓库。
Mail list
You can contact us through our mail list. All mails from this list will be archived to here.
Architecture
The first stable micro-architecture of XiangShan is called Yanqihu (雁栖湖) on this branch, which has been developed since June 2020. The current version of XiangShan, also known as Nanhu (南湖), is still under development on the master branch.
The micro-architecture overview is shown below.
Sub-directories Overview
Some of the key directories are shown below.
.
├── fpga # supported FPGA boards and files to build a Vivado project
├── read-to-run # pre-built simulation images
├── scripts # scripts for agile development
└── src
├── test # test files (including diff-test, module-test, etc.)
└── main/scala # design files
├── bus/tilelink # tilelink utils
├── device # virtual device for simulation
├── difftest # diff-test chisel interface
├── system # SoC wrapper
├── top # top module
├── utils # utilization code
├── xiangshan # main design code
└── xstransforms # some useful firrtl transforms
Generate Verilog
- Run
make verilog
to generate verilog code. The output file isbuild/XSTop.v
. - Refer to
Makefile
for more information.
Run Programs by Simulation
Prepare environment
- Set environment variable
NEMU_HOME
to the absolute path of the NEMU project. - Set environment variable
NOOP_HOME
to the absolute path of the XiangShan project. - Set environment variable
AM_HOME
to the absolute path of the AM project. - Install
mill
. Refer to the Manual section in this guide. - Clone this project and run
make init
to initialize submodules.
Run with simulator
- Install Verilator, the open-source Verilog simulator.
- Run
make emu
to build the C++ simulator./build/emu
with Verilator. - Refer to
./build/emu --help
for run-time arguments of the simulator. - Refer to
Makefile
andverilator.mk
for more information.
Example:
make emu CONFIG=MinimalConfig SIM_ARGS=--disable-log EMU_THREADS=2 -j10
./build/emu -b 0 -e 0 -i ./ready-to-run/coremark-2-iteration.bin --diff ./ready-to-run/riscv64-nemu-interpreter-so
Acknowledgement
In the development of XiangShan, some sub-modules from the open-source community are employed. All relevant usage is listed below.
Sub-module | Source | Detail |
---|---|---|
L2 Cache/LLC | Sifive block-inclusivecache | We enhance the function and the timing of the original module, finally turning it into a Cache generator that can be configured as L2/LLC. |
Diplomacy/TileLink | Rocket-chip | We reused the diplomacy framework and TileLink utility that exist in rocket-chip to negotiate bus. |
FPU | Berkeley hardfloat | We use Berkeley-hardfloat as our FPU and implement an SRT-4 div/sqrt unit for it. Additionally, we split the FMA pipeline to optimize the timing. |
We are grateful for the support of the open-source community and encourage other open-source projects to reuse our code within the scope of the license.