get_immutable_header_offset
return get_field(memory, get_immutable_header_offset(list_number),
set_field(start, memory, get_immutable_header_offset(list_number),
if (get_immutable_start(memory, 0) != get_immutable_header_offset(list_count + 1))
free_bits -= get_immutable_header_offset(1);
offset = get_immutable_header_offset(n_lists + 1);