.. _cross_compilation_setup:

Cross Compilation Environment
#############################

The SiMa DevKit comes pre-flashed with SiMa's Yocto Linux, a build system designed for creating custom Linux distributions tailored to embedded systems. 
Unlike Ubuntu, Yocto Linux does not include a package manager like ``apt``.

Developers can create `custom Yocto builds <https://github.com/SiMa-ai/meta-simaai/blob/master/documentation/build-manual.rst>`_ by introducing their 
own recipes or use the SiMa-provided Yocto SDK to cross-compile applications and third-party components from source code.

For developers new to setting up a Yocto Linux build, it is still possible to build applications that run on the SiMa-provided Linux distribution.

To setup cross compilation environment, follow the steps below:

.. code:: bash

    user@palette-container-id:/home/docker/{project}$ source /opt/poky/4.0.23/environment-setup-cortexa65-poky-linux 

.. note:: 

    The Yocto version may change from the above example when you update Palette. 

This setup configures the build environment to use the right toolchain and libraries for cross-compilation. The following commands shows various tools such as ``CXX`` and how they are configured:

.. code:: bash

    user@palette-container-id:/home/docker/{project}$ env | grep -E 'CC|CXX|LD|SYSROOT|CROSS|TARGET'
        OECORE_TUNE_CCARGS= -mcpu=cortex-a65 -march=armv8.2-a+crypto -mbranch-protection=standard -mabi=lp64
        SDKTARGETSYSROOT=/opt/poky/4.0.23/sysroots/cortexa65-poky-linux
        TARGET_PREFIX=aarch64-poky-linux-
        OECORE_TARGET_OS=linux
        CXX=aarch64-poky-linux-g++  -mcpu=cortex-a65 -march=armv8.2-a+crypto -mbranch-protection=standard -mabi=lp64 -fstack-protector-strong  -O2 -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security --sysroot=/opt/poky/4.0.23/sysroots/cortexa65-poky-linux
        CXXFLAGS= -O2 -pipe -g -feliminate-unused-debug-types 
        OECORE_NATIVE_SYSROOT=/opt/poky/4.0.23/sysroots/x86_64-pokysdk-linux
        LDFLAGS=-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed  -Wl,-z,relro,-z,now
        OECORE_TARGET_SYSROOT=/opt/poky/4.0.23/sysroots/cortexa65-poky-linux
        LD=aarch64-poky-linux-ld  --sysroot=/opt/poky/4.0.23/sysroots/cortexa65-poky-linux
        OECORE_TARGET_ARCH=aarch64
        PKG_CONFIG_SYSROOT_DIR=/opt/poky/4.0.23/sysroots/cortexa65-poky-linux
        CC=aarch64-poky-linux-gcc  -mcpu=cortex-a65 -march=armv8.2-a+crypto -mbranch-protection=standard -mabi=lp64 -fstack-protector-strong  -O2 -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security --sysroot=/opt/poky/4.0.23/sysroots/cortexa65-poky-linux
        CROSS_COMPILE=aarch64-poky-linux-