def _get_assembler(cc_toolchain):
    """Find the path to riscv-unknown-elf-as."""

    # Note: the toolchain config doesn"t appear to have a good way to get
    # access to the assembler.  We should be able to access it via the
    # the compiler, but I had trouble with //hw/ip/otbn/util/otbn-as invoking
    # the compiler as assembler.
    return [f for f in cc_toolchain.all_files.to_list() if f.basename.endswith("as")][0]