xzores / patmos

Patmos is a time-predictable VLIW processor, and the processor for the T-CREST project

About Patmos

Patmos is a time-predictable VLIW processor. Patmos is the processor for the T-CREST project. See also: http://www.t-crest.org/ and http://patmos.compute.dtu.dk/

The Patmos Reference Handbook contains build instructions in Section 5.

For questions and discussions join the Patmos mailing list at: https://groups.yahoo.com/group/patmos-processor/

Getting Started

Several packages need to be installed. The following apt-get lists the packages that need to be installed on a Ubuntu Linux:

sudo apt install git openjdk-8-jdk gitk cmake make g++ texinfo flex bison \
  subversion libelf-dev graphviz libboost-dev libboost-program-options-dev ruby-full \
  liblpsolve55-dev python zlib1g-dev gtkwave gtkterm scala autoconf libfl2 expect

Make sure to use Java 8 and remove any later Java version with sudo apt autoremove.

Install sbt according to the instructions from sbt download

We assume that the T-CREST project will live in $HOME/t-crest. Before building the compiler, add the path to the compiler executables into your .bashrc or .profile:

export PATH=$PATH:$HOME/t-crest/local/bin

Use an absolute path as LLVM cannot handle a path relative to the home directory (~). Logout and login again to make your new PATH setting active.

In order to build the C++ emulator of Patmos, Verilator version 4.028 or higher must be installed.
With Ubuntu 20.04 this can be installed through apt-get:

sudo apt-get install verilator

Older versions of Ubuntu must install Verilator via their git repository:

git clone https://github.com/verilator/verilator
unset VERILATOR_ROOT
cd verilator
git checkout v4.028 #Tested version - newer should be fine
autoconf
./configure
make
sudo make install

You can remove the verilator repository after installation

Patmos and the compiler can be checked out from GitHub and are built as follows:

mkdir ~/t-crest
cd ~/t-crest
git clone https://github.com/t-crest/patmos-misc.git misc
./misc/build.sh

For developers with push permission the ssh based clone string is:

git clone [e-mail]:t-crest/patmos-misc.git misc

build.sh will checkout several other repositories (the compiler, library, and the Patmos source) and build the compiler and the Patmos simulator. Therefore, take a cup of coffee and find some nice reading (e.g., the Patmos Reference Handbook).

We can start with the standard, harmless looking Hello World:

main() {
    printf("Hello Patmos!\n");
}

With the compiler installed it can be compiled to a Patmos executable and run with the simulator as follows:

patmos-clang hello.c
pasim a.out

However, this innocent examples is quiet challenging for an embedded system. For further details and how to build Patmos for an FPGA see Section 6 in the Patmos Reference Handbook.

You can also build the Patmos handbook yourself from the source. You first need to install LaTeX (about 3 GB) with:

sudo apt-get install texlive-full doxygen

The handbook is then built with:

cd patmos/doc
make