pythondata-cpu-vexriscv

About this fork

This is a fork from the default set of Litex Vexriscv configurations because:

• None of the default configs are a perfect fit for our needs
• We've been tracing through some bugs in MMU implementation which makes the fork really handy
• We can tune caches and other features to optimize performance for our specific chip

We have a fairly unusual chip (-1L speedgrade) in that it is slower than most others, favoring low power dissipation over raw speed. This has made some speed tuning essential, and for several reasons it's impractical to simply adjust the sysclk speed to the edge of routing failure. Thus we have resorted to some architectural changes in the CPU to gain performance while keeping routability acceptable.

It also allows us to have some stewardship over the CPU code base, which is nice for inspectability and traceability reasons.

Original README

Non-Python files needed for the cpu vexriscv packaged into a Python module so they can be used with Python libraries and tools.

This Useful for usage with tools like LiteX.

The data files can be found under the Python module pythondata_cpu_vexriscv. The pythondata_cpu_vexriscv.data_location value can be used to find the files on the file system.

Example of getting the data file directly;

import pythondata_cpu_vexriscv

my_data_file = "abc.txt"

with open(os.path.join(pythondata_cpu_vexriscv.data_location, my_data_file)) as f:
    print(f.read())

Example of getting the data file using litex.data.find API;

from pythondata_cpu_vexriscv import data_file

my_data_file = "abc.txt"

with open(data_file(my_data_file)) as f:
    print(f.read())

The data files are generated from https://github.com/SpinalHDL/VexRISCV.git and place in the directory pythondata_cpu_vexriscv/verilog.

Installing from git repository

Manually

You can install the package manually, however this is not recommended.

git clone https://github.com/litex-hub/pythondata-cpu-vexriscv.git
cd pythondata-cpu-vexriscv
sudo python setup.py install

Using pip with git repository

You can use pip to install the data package directly from github using;

pip install --user git+https://github.com/litex-hub/pythondata-cpu-vexriscv.git

If you want to install for the whole system rather than just the current user, you need to remove the --user argument and run as sudo like so;

sudo pip install git+https://github.com/litex-hub/pythondata-cpu-vexriscv.git

You can install a specific revision of the repository using;

pip install --user git+https://github.com/litex-hub/pythondata-cpu-vexriscv.git@<tag>
pip install --user git+https://github.com/litex-hub/pythondata-cpu-vexriscv.git@<branch>
pip install --user git+https://github.com/litex-hub/pythondata-cpu-vexriscv.git@<hash>

With requirements.txt file

Add to your Python requirements.txt file using;

-e git+https://github.com/litex-hub/pythondata-cpu-vexriscv.git

To use a specific revision of the repository, use the following;

-e https://github.com/litex-hub/pythondata-cpu-vexriscv.git@<hash>

Installing from PyPi

Using pip

pip install --user pythondata-cpu-vexriscv