__futex_cas_op
__futex_cas_op("mov\t%4, %1", ret, oldval, uaddr, oparg);
__futex_cas_op("add\t%2, %4, %1", ret, oldval, uaddr, oparg);
__futex_cas_op("or\t%2, %4, %1", ret, oldval, uaddr, oparg);
__futex_cas_op("andn\t%2, %4, %1", ret, oldval, uaddr, oparg);
__futex_cas_op("xor\t%2, %4, %1", ret, oldval, uaddr, oparg);