read_rw
if (read_rw(tf->tf_out[6], &pcb->pcb_rw[0])) {
if (rwindow_save(l) || read_rw(tf->tf_out[6], &pcb->pcb_rw[0])) {
if (read_rw(pcb->pcb_rw[0].rw_in[6], &pcb->pcb_rw[1])) {