NEXT_QUEUED_SCB_ADDR
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 0, busaddr & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 1, (busaddr >> 8) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 2, (busaddr >> 16) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 3, (busaddr >> 24) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 0, busaddr & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 1, (busaddr >> 8) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 2, (busaddr >> 16) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 3, (busaddr >> 24) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 0, busaddr & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 1, (busaddr >> 8) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 2, (busaddr >> 16) & 0xFF);
ahd_outb(ahd, NEXT_QUEUED_SCB_ADDR + 3, (busaddr >> 24) & 0xFF);