Cross-building RISC OS (changes)

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RISC OS’ sources have some support for cross-building from a Unix-style environment. At present support is somewhat incomplete, neglected, broken and undocumented. This page aims to document some deduction of the process by trial and error. It is likely there are mistakes – feel free to correct them.

RISC OS’ primary toolchain is its own Desktop Development Environment and the closed-source Norcroft compiler. When cross-building, the favoured compiler is a build of Norcroft for Linux or other platform. However it’s possible to make some progress using GCC.

The build involves sourcing some scripts into your shell environment – supposedly this will work with several shells, but for now we’ll assume you’re using bash on Linux (or WSL). Other platforms may run into different issues.

To set up the build tools:

1. Build GCCSDK for your chosen platform. We’ll assume you have installed it in /home/riscos for the purposes of this guide (ie the cross compiler in /home/riscos/cross and other tools in /home/riscos/env)
2. Fetch the cross-tools
   

   
   git clone https://gitlab.riscosopen.org/Products/CrossTools.git
   cd CrossTools
   git submodule update --init --remote
   export CROSSTOOLS=$(pwd)
   

3. Configure your environment for building tools using native GCC/etc
   

   
   export GCCSDK_INSTALL_CROSSBIN=/home/riscos/cross/bin
   cd $CROSSTOOLS/RiscOS/Env/ROOL
   source CrossTools.sh
   

4. Export symbols from some libraries
   

   
   cd $CROSSTOOLS/RiscOS/Sources/Lib/RISC_OSLib
   make export
   cd $CROSSTOOLS/RiscOS/Sources/Lib/CLXLite
   make export
   

5. Build srcbuild (currently using a fork untilPR7 is merged)
   

     cd $CROSSTOOLS mkdir -p RiscOS/Utilities/Release #git git clone https://gitlab.riscosopen.org/RiscOS/Utilities/Release/srcbuild.git RiscOS/Utilities/Release/srcbuild git clone https://gitlab.riscosopen.org/tmarkettos/srcbuild.git RiscOS/Utilities/Release/srcbuild cd $CROSSTOOLS/RiscOS/Utilities/Release/srcbuild git checkout cross-execvpe make install

6. Create a new terminal (for a fresh build environment) and run the below in it
7. Fetch the sources you want to build (eg BCM2835 for Raspberry Pi)
   

   
   git clone https://gitlab.riscosopen.org/Products/BCM2835.git
   cd BCM2835
   git submodule update --init --remote
   export TREE=$(pwd)
   

8. Symlink the srcbuild binary into this new tree and add it to your PATH
   

   
   export CROSSTOOLS=<path to your CrossTools folder>
   cd $TREE
   mkdir -p RiscOS/Install/srcbuild
   ln -s $CROSSTOOLS/RiscOS/Install/srcbuild/srcbuild $TREE/RiscOS/Install/srcbuild/srcbuild
   export PATH=$PATH:$TREE/RiscOS/Install/srcbuild
   

9. You can now use srcbuild to perform build actions, eg:
   

   
   export GCCSDK_INSTALL_CROSSBIN=/home/riscos/cross/bin
   export TOOLCHAIN=GNU  # don't use Norcroft
   source $TREE/RiscOS/Env/ROOL/BCM2835.sh
   cd $TREE/RiscOS
   srcbuild list
   

srcbuild is designed to orchestrate the stages of the build process, in the same way as Builder . However, at this point can’t go much further because some of the Makefiles are no longer cross-compile friendly. A task for the eager reader is to fix them up…

See also

Cross-build forum thread from 2010
riscos.info wiki article from 2008-12