rw_rtn
uintptr_t rw_rtn;
((struct rwindow *)frame)->rw_rtn;
if (frame.rw_rtn == 0)
fsip->fsi_stack[fsip->fsi_depth++] = frame.rw_rtn;
uintptr_t rw_rtn;
pc = (uintptr_t)rwin.rw_rtn;
pc = (uint32_t)rwin.rw_rtn;