MBOX0
switch (sbus_readw(qpti->qregs + MBOX0)) {
case 1: sbus_writew(param[0], qpti->qregs + MBOX0);
if (sbus_readw(qpti->qregs + MBOX0) & 0x4000)
while (--loop_count && (sbus_readw(qpti->qregs + MBOX0) == 0x04))
case 1: param[0] = sbus_readw(qpti->qregs + MBOX0);
while (--loop_count && ((sbus_readw(qpti->qregs + MBOX0) & 0xff) == 0x04))