BSYO
ahd_outb(ahd, SCSISIGO, P_MESGOUT | BSYO);
ahd_outb(ahd, SCSISIGO, P_MESGIN | BSYO);
ahc_outb(ahc, SCSISIGO, P_MESGOUT | BSYO);
ahc_outb(ahc, SCSISIGO, P_MESGIN | BSYO);