PITCTL_PORT
outb(PITCTL_PORT, PIT_C0 | PIT_LOADMODE | PIT_ENDSIGMODE);
outb(PITCTL_PORT, 0); /* latch counter 0 */
outb(PITCTL_PORT, (PIT_C0|PIT_NDIVMODE|PIT_READMODE));
outb(PITCTL_PORT, PIT_READBACK | PIT_READBACKC0);
outb(PITCTL_PORT, PIT_C0 | PIT_LOADMODE | PIT_ENDSIGMODE);
outb(PITCTL_PORT, PIT_C2 | PIT_READMODE | PIT_RATEMODE);