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    A source library xPack with the µOS++ QEMU RISC-V board support files

    This project provides the device-qemu-riscv source library as an xPack dependency and includes the initialization code required to build applications running on the QEMU RISC-V boards.

    It is intended to be included in unit tests, which generally do not need peripherals.

    The project is hosted on GitHub as micro-os-plus/devices-qemu-riscv-xpack.

    Maintainer info

    This page is addressed to developers who plan to include this source library into their own projects.

    For maintainer info, please see the README-MAINTAINER file.


    As a source library xPack, the easiest way to add it to a project is via xpm, but it can also be used as any Git project, for example as a submodule.


    A recent xpm, which is a portable Node.js command line application.

    For details please follow the instructions in the xPack install page.


    This package is available from as @micro-os-plus/devices-qemu-riscv from the registry:

    cd my-project
    xpm init # Unless a package.json is already present
    xpm install @micro-os-plus/devices-qemu-riscv@latest
    ls -l xpacks/micro-os-plus-devices-qemu-riscv

    Git submodule

    If, for any reason, xpm is not available, the next recommended solution is to link it as a Git submodule below an xpacks folder.

    cd my-project
    git init # Unless already a Git project
    mkdir -p xpacks
    git submodule add \


    Apart from the unused master branch, there are two active branches:

    • xpack, with the latest stable version (default)
    • xpack-develop, with the current development version

    All development is done in the xpack-develop branch, and contributions via Pull Requests should be directed to this branch.

    When new releases are published, the xpack-develop branch is merged into xpack.

    Developer info


    QEMU implements several RISC-V boards, which can be used for running tests.

    This project provides the initialization code required to build applications running on these boards.


    The devices-qemu-riscv source library is fully functional, but minimalistic, for running semihosted tests.


    The emulated boards provide a limited range of peripherals, but for running unit tests these peripherals are not necessary.

    The current initialisation code does not touch them.

    Build & integration info

    The project is written in C++ and assembly and it is expected to be used in C and C++ projects.

    The source code was compiled with riscv-none-elf-gcc 12 and should be warning free.

    To ease the integration of this package into user projects, there are already made CMake and meson configuration files (see below).

    For other build systems, consider the following details:

    Include folders

    The following folders should be passed to the compiler during the build:

    • include

    The header files to be included in user project are:

    #include <micro-os-plus/device.h>

    Source files

    The source files to be added to user projects are:

    • src/reset-entry.S

    Preprocessor definitions

    • none

    Compiler options

    • -std=c++20 or higher for C++ sources
    • -std=c11 for C sources

    Interrupt handlers

    • none yet

    C++ Namespaces

    • none

    C++ Classes

    • none


    • none


    To integrate the devices-qemu-riscv source library into a CMake application, add this folder to the build:


    The result is an interface library that can be added as an application dependency with:

    target_link_libraries(your-target PRIVATE


    To integrate the devices-qemu-riscv source library into a meson application, add this folder to the build:


    The result is a dependency object that can be added to an application with:

    exe = executable(
      link_with: [
        # Nothing, not static.
      dependencies: [



    Known problems

    • none



    Change log - incompatible changes

    According to semver rules:

    Major version X (X.y.z | X > 0) MUST be incremented if any backwards incompatible changes are introduced to the public API.

    The incompatible changes, in reverse chronological order, are:

    • v1.x: initial release


    The original content is released under the MIT License, with all rights reserved to Liviu Ionescu.


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