kratos-runtime 0.0.5

Kratos runtime for debugging

Kratos Debugger Runtime

This is the runtime library required to debug Kratos hardware designs. You need a C++17 compatible compiler, such as g++-8 to compile the library.

How to use Kratos-Runtime

The following instruction is based on Linux and tested against Verilator and ncsim.

$ git clone https://github.com/Kuree/kratos-runtime
$ cd kratos-runtime
$ git submodule update --init --recursive
$ mkdir build
$ cd ./build
$ cmake ..
$ make -j

After that, you can find the library as build/src/libkratos-runtime.so. You can either copy that library to any place you like or simply use symbolic link.

Generate Kratos-Runtime debug database for your design

When calling verilog() function, you can supply another argument called debug_db_filename to specify the location where kratos can output the debug files,

verilog(design, debug_db_filename="debug.db")

Using Kratos-runtime with Verilator

Once you have compiled the shared library, you can ask verialtor to link your test bench with kratos-runtime. Before you do that, since we need to read the internal signals, we need to inject verilator specific info via a pass:

_kratos.passes.insert_verilator_public(design.internal_generator)

_kratos is the namespace for native C++ binding, you can use it via import _kratos.

When invoking the verilator command, you need to specify the kratos runtime name as well as --vpi switch, for instance:

verilator --cc design.sv test_tb.sv libkratos-runtime.so --vpi --exe

You can symbolic link libkratos-runtime.so inside obj_dir so that the linker and find it easily.

Once the test bench is compiled, you need to use LD_LIBRARY_PATH to let the system to load, such as

$ LD_LIBRARY_PATH=./obj_dir/ ./obj_dir/Vtest

Or you can let the linker to fix the shared library path in the verilator, which is beyond the scope of this tutorial.

Using kratos-runtime with Ncsim

Ncsim is much easier to use than verilator. Once you have the design, simply tell the simulator that you want to load the vpi and dpi library, such as

irun test_tb.sv test.sv -sv_lib libkratos-runtime.so -loadvpi libkratos-runtime.so:initialize_runtime_vpi -access +r

-access +r is necessary to allow the runtime to read out simulation variables.

What to do after launch the simulation

You can now use any debugger that's compatible with the Kratos debug protocol. Kratos has provide an open-source version of debugger extension inside VS Code. You can install it here and use it to debug your design.