PIT_CH0
outb_p(LATCH & 0xff, PIT_CH0); /* LSB */
outb_p(LATCH >> 8, PIT_CH0); /* MSB */
outb_p(0, PIT_CH0);
outb_p(0, PIT_CH0);
outb_p(PIT_LATCH & 0xff, PIT_CH0); /* LSB */
outb_p(PIT_LATCH >> 8, PIT_CH0); /* MSB */
outb_p(delta & 0xff , PIT_CH0); /* LSB */
outb_p(delta >> 8 , PIT_CH0); /* MSB */
count = inb_p(PIT_CH0); /* read the latched count */
count |= inb_p(PIT_CH0) << 8;
outb_p(PIT_LATCH & 0xff, PIT_CH0);
outb_p(PIT_LATCH >> 8, PIT_CH0);