SCB_SGPTR
if ((ahd_inb_scbram(ahd, SCB_SGPTR) & SG_LIST_NULL) == 0
&& ((ahd_inb_scbram(ahd, SCB_SGPTR) & SG_FULL_RESID) != 0
ahd_outb(ahd, SCB_SGPTR,
ahd_inb_scbram(ahd, SCB_SGPTR)
sgptr = ahd_inl_scbram(ahd, SCB_SGPTR) & ~SG_FULL_RESID;
ahd_outb(ahd, SCB_SGPTR, sgptr);
ahd_outl(ahd, SCB_SGPTR, sgptr);
ahd_outb(ahd, SCB_SGPTR,
ahd_inb_scbram(ahd, SCB_SGPTR) | SG_LIST_NULL);
ahd_inl_scbram(ahd, SCB_SGPTR),