NVRAM_CENTURY
static int centb = NVRAM_CENTURY;
cmoscentury = mc146818_read(NULL, NVRAM_CENTURY);
cmoscentury = mc146818_read(NULL, NVRAM_CENTURY);
mc146818_write(NULL, NVRAM_CENTURY,
mc146818_write(NULL, NVRAM_CENTURY, century); /* XXX softc */
rtc.regs[NVRAM_CENTURY] = TOBCD((gnow->tm_year + 1900) / 100);