MBA_RCSR
while (MBA_RCSR(MBA_SR) & MBASR_DTBUSY)
if (MBA_RCSR(MBA_SR) & MBACR_ABORT)
while (MBA_RCSR(MBA_SR) & MBASR_DTBUSY)
if ((MBA_RCSR(MUREG(i, MU_DS)) & MBADS_DPR) == 0)
ma.ma_type = MBA_RCSR(MUREG(i, MU_DT)) & 0xf1ff;
itype = MBA_RCSR(MBA_SR);
attn = MBA_RCSR(MUREG(0, MU_AS)) & 0xff;