AscFindSignature
if (!AscFindSignature(iop_base))
if (!AscFindSignature(ioport)) {
if (!AscFindSignature(asc_dvc->iop_base)) {
if (AscFindSignature(asc_dvc->iop_base)) {
if (!AscFindSignature(asc_dvc->iop_base)) {