Important disclaimer:

This is not an officially supported Google product

Embedded Shell

A Terminal like interface over UART.

• Targeted at embedded systems engineers and researchers who want to explore the hardware by writing small functions that can be triggered from a shell like interface.
• A UART based shell that enables finer control of CPU by allowing functions to be exposed as commands to be triggered from the prompt.
• Low memory footprint of < 4kB

this is a perfect tool for getting up and running with a new board in less than 1 hour.

Features:

• Low footprint shell implementation.
• Commands with same foot print as int main(int argc, char* argv[]){}
• Export function as command using a macro (ADD_CMD() available in shell.h).
• Supported Languages: C, C++ and Assembly.
• Automatic source file discovery
  • .c, .cpp and .S source files in the Project and shell directory are automatically picked for compilation (No need to modify any Makefile. The build system automatically figrues the source files).
• Automatic Header discovery.
  • location for .h and .hpp files is automatically passed to the compiler for header file lookup.

Supported Processors/Architectures

examples/ implements a hello world example for the processor variety listed below:

Quick Setup

Execute ./manage -s or .scripts/setup to install all the dependencies.

Quick Demo

Following is a run of example in examples/emulation/riscv-64

cd examples/emulation/riscv-64
make
make run

If you haven't done the Quick Setup as noted above, you'll need to install following utilities:

sudo apt install -y binutils make binutils-riscv64-linux-gnu gcc-riscv64-linux-gnu g++-riscv64-linux-gnu \
                    qemu-system-riscv64

wget -P ~ https://git.io/.gdbinit

pip3 install pygments

Further, gdb based debugging can also be done by running the following commands in two separate terminals:

make debug

and

make gdb

You should see similar output as in above visual.

Documentation

• To be able to run all the example and create your own project follow the documentation in docs/.
• It also provides details about the internal workings of shell and how to setup your own project.

Table of contents

Contributing

Source Code Headers

Every file containing source code must include copyright and license information. This is to help well-intentioned people avoid accidental copying that doesn't comply with the license.

Apache header:

Copyright 2021 Google LLC

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.