Differences in programming 8-bit ADC and 12-bit ADC

Hi,

I am currently trying to modify an existing code to display 12 bit data (C8051F206) instead of 8 bit data (C8051F226).

When I download the existing codes and run the program, my LCD is able to display some values. However, when I modify the program to display 12 bit data, the LCD just show 0.000V when I adjusted the ADC input. May I know what is different in the ADC configuration that I have to change ? What is wrong with my 12 bit code?

8-bit code:

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------
        unsigned int q,value,temp;
        unsigned char a,b,c,d;
        float bit_value,result;
/*------------------
// ADC Conversion
 -------------------*/

void adcdata()
{

                ADCINT = 0;


                ADBUSY = 1;
                ldelay(100);

                while(ADCINT==0);

                value = ADC0L;
                value = value*256;
                ldelay(900);

                ldelay(1000);
                ADCINT=0;
                ADBUSY=0;

}

/*------------------------------------------------------
// Bit Resolution: result = Voltage reference*(255/256)
 -------------------------------------------------------*/

void bit_resolution()
{

        bit_value = 3.2/(256);
        result = value*bit_value;
}

My 12 bit code (Left justified ADCOH:ADCOL):

//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------
        unsigned int q,value,value1,temp,totvalue;
        unsigned char a,b,c,d,e;
/*------------------
// ADC Conversion
 -------------------*/

void adcdata()
{

                ADCINT = 0;
                value=0;

                ADBUSY = 1;
                ldelay(100);

                while(ADCINT==0);
                value = ADC0L;
                e= 0x0F & ADC0H;
                value1=e;
                totvalue= value + value1*256;
                ldelay(900);

                ldelay(1000);
                ADCINT=0;
                ADBUSY=0;

}

Appreciate if anyone could help. Thanks!!