STM8s003 fluctuating ADC value

#include <iostm8s003f3.h>
#include "stm8s.h"

unsigned int AD_Value,TIMER4 = 0;
unsigned long int VIR,VOR,VI,VO;
int main(void)
{
       
   
   CLK_ICKR |= (1<<0);           	//HSIEN=1 //HSI Oscilator Enable
     // CLK_CKDIVR &=~((1<<4)|(1<<3)|(1<<2)|(1<<1)|(1<<0));
  // CLK_CKDIVR |= (1<<4)|(1<<3);  	//Fmaster = 2MHz. Default clock - 16MHz, Prescaler - 8
	//CLK_CKDIVR |= (1<<0);         	//CPU Clock = Fmaster/2 - Prescaler selected 2

     
      
      ADC_INIT();
      PD_ODR |=((1<<4)|(1<<5)|(1<<6));
      INITTIMER4();
    
      
      while(1)
      {
        ADC();
     }
}


int ADC()
    {
      DELAY(1);
     AV=VIR=VOR=0;
   while(AV<=1999)
     {
       VOR=VOR+(READADC(4));   
      AV++;
      VIR=VIR+(READADC(3));
      
      
      }
      VIR=(VIR/2000) ;
      VOR=(VOR/2000) ;
      
  
      VO=VOR;
      VI=VIR;
      return 0;
      
    }

void ADC_INIT()
{
      ADC_CR2 &=~(1<<1);
      ADC_CR1 |=(1<<1);
      ADC_CR1 &=~((1<<6)|(1<<4)|(1<<5));
      ADC_CR2 &= ~(1<<3); 
      ADC_CR2=0;
      ADC_CR3=0;
      ADC_CR1 &= ~((1<<4)|(1<<5)|(1<<6));   
      ADC_CR1 |= (1<<0); // ADC ON
}

unsigned int READADC(unsigned char CHANNEL) 
{
  AD_Value =0;
  ADC_CSR = ((0x0F)&CHANNEL);                   //Channel Selected
  ADC_CR1 |= (1<<0);                                  //ADON -> 1
  while(!(ADC_CSR&(1<<7)));                           //Wait while EOC is 0 | while ADC is running
  AD_Value =((((unsigned int)ADC_DRH)<<2)+ADC_DRL);  //ADC Value copied in AD_Value
  ADC_CSR &= ~(1<<7);   
  return AD_Value;
 }

void INITTIMER4()
{
  TIM4_CR1 |=0x01;                 //Enable timer
  CLK_PCKENR1 |=(1<<4);         //Enable peripheral clock for timer 4
  TIM4_PSCR |=0X0a;              //clock prescaler, divide by max
  TIM4_IER |=0x01;                  //enable update interrupt
   
   asm("rim");                   //Enable global interrupt
}

#pragma vector=0x19
__interrupt void TIM4_UPD_OVR_IRQHANDLER(void)
{
  if(TIMER4 > 100)
  { 
    DISP(VI);   // this function is only displaying on seven segment
    
    TIMER4=0;
  }
  TIMER4++;
  TIM4_SR &=~(1<<0);
}

void ADC_Init (unsigned char Channel)
{
  CLK->PCKENR2 |= CLK_PCKENR2_ADC;
  ADC1->TDRL = Channel;
  ADC1->CR1 = ADC1_PRESSEL_FCPU_D18;
  ADC1->CR2 = ADC1_ALIGN_RIGHT;
  ADC1->CR1 |= ADC1_CR1_ADON;
}

unsigned int ADC_Read (unsigned char Channel)
{
  unsigned int Result;
  ADC1->CSR = Channel;
  ADC1->CR1 |= ADC1_CR1_ADON;
  ADC1->CR1 |= ADC1_CR1_ADON;
  while (!(ADC1->CSR & ADC1_CSR_EOC));
  Result = ADC1->DRL;
  Result |= ADC1->DRH << 8;
  
  return Result;  
}