CALIBRATE_LATCH
outb(CALIBRATE_LATCH & 0xff, 0x42); /* LSB of count */
outb(CALIBRATE_LATCH >> 8, 0x42); /* MSB of count */
return ((long)cc * PIT_TICK_RATE) / (CALIBRATE_LATCH + 1);
outb_p(CALIBRATE_LATCH & 0xff, 0x42); /* LSB of count */
outb_p(CALIBRATE_LATCH >> 8, 0x42); /* MSB of count */
((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (PIT_TICK_RATE>>10))