com_dlbl
outb(COMPORT + com_dlbl, COMC_BPS(COMSPEED) & 0xff);
if (sio_getreg(com, com_dlbl) != dlbl)
sio_setreg(com, com_dlbl, dlbl);
dlbl = inb(iobase + com_dlbl);
sp->dlbl = inb(iobase + com_dlbl);
outb(iobase + com_dlbl, dlbl);
if (sp->dlbl != inb(iobase + com_dlbl))
outb(iobase + com_dlbl, sp->dlbl);
outb(iobase + com_dlbl, divisor & 0xff);
sio_setreg(com, com_dlbl, divisor & 0xff);