STEP
w->allociovecs = min(STEP, w->maxiovecs);
w->allociovecs = min(w->allociovecs + STEP, w->maxiovecs);
ahd_outb(ahd, SEQCTL0, ahd_inb(ahd, SEQCTL0) | STEP);
ahd_outb(ahd, SEQCTL0, ahd_inb(ahd, SEQCTL0) & ~STEP);
ahc_outb(ahc, SEQCTL, ahc->seqctl | STEP);
STEP;
STEP;
STEP;
STEP;