LibraryKernel

• The libscarv library is a set of individual kernels; the associated implementation is housed in

  ${REPO_HOME}/src/libscarv/${KERNEL}

  and built by providing

  ${REPO_HOME}/src/libscarv/${KERNEL}/Makefile.in

  for the build system to include.

• The directory housing a kernel implementation is structured per

  ${REPO_HOME}/src/libscarv/${KERNEL}
  ${REPO_HOME}/src/libscarv/${KERNEL}/native
  ${REPO_HOME}/src/libscarv/${KERNEL}/riscv
  ${REPO_HOME}/src/libscarv/${KERNEL}/riscv-xcrypto

  i.e., there are sub-directories for each target architecture. Note that:

  • The top-level directory for a given kernel (i.e., ${REPO_HOME}/src/libscarv/${KERNEL}) houses an architecture-agnostic implementation. This implementation may be either

    • incomplete, meaning it must be combined with supporting, architecture-specific functionality (i.e., cannot be used as a stand-alone kernel),
    • complete, meaning it may be combined with supporting, architecture-specific functionality (i.e., can be used as a stand-alone kernel).

  • If supporting, architecture-specific functionality is used, the target architecture (sub-)directory (i.e., ${REPO_HOME}/src/libscarv/${KERNEL}/${ARCH}) houses it.

  • Within a given target architecture (sub-)directory,

    • X_imp.S captures the architecture-specific implementation of some functionality X,
    • macro.S captures macros that support said implementation(s).