PROTECT          2833 gc/os_dep.c              PROTECT(start, len);
PROTECT          2865 gc/os_dep.c    		PROTECT(current_start, (ptr_t)current - (ptr_t)current_start);
PROTECT          2873 gc/os_dep.c    	    PROTECT(current_start, (ptr_t)current - (ptr_t)current_start);