关于STM32的RTC设置年份不正确的问题

rt_enter_critical();
/* converts calendar time time into local time. */
tm_now = localtime((const time_t *)args);
/* copy the statically located variable */
memcpy(&now, tm_now, sizeof(struct tm));
/* unlock scheduler. */
rt_exit_critical();
switch (cmd)
{
case RT_DEVICE_CTRL_RTC_GET_TIME:
{
    RTC_GetTime(RTC_Format_BIN, &sTime);
    RTC_GetDate(RTC_Format_BIN, &sDate);
    now.tm_hour = sTime.RTC_Hours;
    now.tm_min = sTime.RTC_Minutes;
    now.tm_sec = sTime.RTC_Seconds;
    now.tm_year = sDate.RTC_Year + 100;
    now.tm_mon = sDate.RTC_Month - 1;
    now.tm_mday = sDate.RTC_Date;
    *((time_t *)args) = mktime(&now);
}
break;
case RT_DEVICE_CTRL_RTC_SET_TIME:
{
    sTime.RTC_Hours = now.tm_hour;
    sTime.RTC_Minutes = now.tm_min;
    sTime.RTC_Seconds = now.tm_sec;
    RTC_SetTime(RTC_Format_BIN, &sTime);
    sDate.RTC_Year = now.tm_year - 100;
    sDate.RTC_Month = now.tm_mon + 1;
    sDate.RTC_Date = now.tm_mday;
    //notice weekday!
    sDate.RTC_WeekDay = now.tm_wday + 1;
    RTC_SetDate(RTC_Format_BIN, &sDate);
}
break;
}
return RT_EOK;