Adc 16f877 8 bit to 10 bit

#include<htc.h>

__CONFIG (0x3F72); //configured fuses
//define ports for easier reading
#define LEDS PORTB

void delay(unsigned char itime);

void main(void)
{
//8bit data-type variables
unsigned char x;	//ADC low byte
unsigned char y;	//ADC high byte
unsigned int z;	//final result

TRISB=0x00; //output
TRISA=0xFF;	//inputs
LEDS=0xFF;	//clear/switch off LEDS

while(1)
{
//ADFM=1, all i/ps analog, +VREF enabled
//Configure the functions of the Port bits
ADCON1=0b10000001;
//clock/channel select & enable bits
//controls the operation of the A/D module
ADCON0=0b11000001;


delay(1);
//Start a2d conversion
//Set GO bit (ADCON0=ADCON0|1;)
GODONE=1;
//wait end-of-conversion (conversion complete)
while(GODONE==1);
x=ADRESL; //store low byte
x=x>>1;	//shift 1 bit to the right
y=ADRESH;	//store high byte
y=y<<7;	//shift left 7 bit position
z=x|y; //combine together
LEDS=~z; //output on leds
}
}

void delay(unsigned char itime)
{
unsigned char i,j;
for(i=0;i<itime;i++)
for(j=0;j<1;j++);
}

z = ADRESL | (ADRESH<<8);