MUREG
unitadr = adpadr + MUREG(bootrpb.unit, 0);
unitadr = adpadr + MUREG(unit, 0);
int unitadr = adpadr + MUREG(bootregs[3], 0);
if ((MBA_RCSR(MUREG(i, MU_DS)) & MBADS_DPR) == 0)
ma.ma_type = MBA_RCSR(MUREG(i, MU_DT)) & 0xf1ff;
ma.ma_ioh = sc->sc_ioh + MUREG(i, 0);
attn = MBA_RCSR(MUREG(0, MU_AS)) & 0xff;
MBA_WCSR(MUREG(0, MU_AS), attn);