XiangShan

XiangShan (香山) is an open-source high-performance RISC-V processor project.

中文说明在此。

Docs and slides

XiangShan-doc is our official documentation repository. It contains design spec., technical slides, tutorial and more.

Micro-architecture documentation of XiangShan has been published. Please check out https://xiangshan-doc.readthedocs.io

Wechat/微信：香山开源处理器

Zhihu/知乎：香山开源处理器

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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 of Nanhu (南湖) is shown below.

xs-arch-nanhu

Sub-directories Overview

Some of the key directories are shown below.

.
├── src
│   └── main/scala         # design files
│       ├── device         # virtual device for simulation
│       ├── system         # SoC wrapper
│       ├── top            # top module
│       ├── utils          # utilization code
│       ├── xiangshan      # main design code
│       └── xstransforms   # some useful firrtl transforms
├── scripts                # scripts for agile development
├── fudian                 # floating unit submodule of XiangShan
├── huancun                # L2/L3 cache submodule of XiangShan
├── difftest               # difftest co-simulation framework
└── ready-to-run           # pre-built simulation images

IDE Support

bsp

make bsp

IDEA

make idea

Generate Verilog

Run make verilog to generate verilog code. The output file is build/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 and verilator.mk for more information.

Example:

make emu CONFIG=MinimalConfig 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

Troubleshooting Guide

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	Our new L2/L3 design are inspired by Sifive’s `block-inclusivecache`.
Diplomacy/TileLink	Rocket-chip	We reused the Diplomacy framework and TileLink utility that exist in rocket-chip to negotiate bus.

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.