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Cadence Tensilica Xtensa C/C++ Compiler (XCC)

  1. Obtain Tensilica Software Development Toolkit targeting the specific SoC on hand. This usually contains two parts:

    • The Xtensa Xplorer which contains the necessary executables and libraries.

    • A SoC-specific add-on to be installed on top of Xtensa Xplorer.

      • This add-on allows the compiler to generate code for the SoC on hand.

  2. Install Xtensa Xplorer and then the SoC add-on.

    • Follow the instruction from Cadence on how to install the SDK.

    • Depending on the SDK, there are two set of compilers:

      • GCC-based compiler: xt-xcc and its friends.

      • Clang-based compiler: xt-clang and its friends.

  3. Make sure you have obtained a license to use the SDK, or has access to a remote licensing server.

  4. Set these environment variables:

    • Set ZEPHYR_TOOLCHAIN_VARIANT to xcc or xt-clang.

    • Set XTENSA_TOOLCHAIN_PATH to the toolchain installation directory.

    • There are two ways to specify the SoC ID and the SDK version to use. They are mutually exclusive, and cannot be used together.

      1. When building for a single SoC:

        • Set XTENSA_CORE to the SoC ID where application is being targeted.

        • Set TOOLCHAIN_VER to the Xtensa SDK version.

      2. When building for multiple SoCs, for each SoC and board combination:

        • Set XTENSA_CORE_{normalized_board_target} to the SoC ID where application is being targeted.

        • Set TOOLCHAIN_VAR_{normalized_board_target} to the Xtensa SDK version.

  5. For example, assuming the SDK is installed in /opt/xtensa, and using the SDK for application development on intel_adsp/ace15_mtpm, setup the environment using the two above mentioned ways:

    1. Single SoC:

      # Linux
export ZEPHYR_TOOLCHAIN_VARIANT=xt-clang
export XTENSA_TOOLCHAIN_PATH=/opt/xtensa/XtDevTools/install/tools/
export XTENSA_CORE=ace10_LX7HiFi4_2022_10
export TOOLCHAIN_VER=RI-2022.10-linux

    2. Multiple SoCs:

      # Linux
export ZEPHYR_TOOLCHAIN_VARIANT=xt-clang
export XTENSA_TOOLCHAIN_PATH=/opt/xtensa/XtDevTools/install/tools/
export TOOLCHAIN_VER_intel_adsp_ace15_mtpm=RI-2022.10-linux
export XTENSA_CORE_intel_adsp_ace15_mtpm=ace10_LX7HiFi4_2022_10

  6. To use Clang-based compiler:

    • Set ZEPHYR_TOOLCHAIN_VARIANT to xt-clang.

    • Note that the Clang-based compiler may contain an old LLVM bug which results in the following error:

      /tmp/file.s: Assembler messages:
/tmp/file.s:20: Error: file number 1 already allocated
clang-3.9: error: Xtensa-as command failed with exit code 1

      If this happens, set XCC_NO_G_FLAG to 1.

      • For example:

        # Linux
export XCC_NO_G_FLAG=1