Sorry for the delay in my response.
The RTC.C code that is generated using the code architect is as follows:

void rtc_init(void)
{
// set reload value
// count frequency = clock source / 128 / RTCH, RTCL
RTCH = 0x0A;
RTCL = 0x00;

// select CPU Clock, enable interrupt source
RTCCON = 0x62;

// initialize watchdog/real time clock interrupt
//watchdogrtc_isrinit();

// start real time clock
RTCCON |= 0x01;
}

void rtc_start(void)
{
// start the real time clock
RTCCON |= 0x01;
}

void rtc_stop(void)
{
// stop the real time clock
RTCCON &= ~0x01;
}

Here, please tell me how to define the RTC registers used in the code (RTCH, RTCL, RTCCON...) for the C8051F120 MCU.