Help me with this code

// Program to interface Sharps distance sensor. Set vref =3v for ADC0804 #include<reg51.h>
 #define port P3
 #define adc_input P1
 #define dataport P0
 #define sec 100
 sbit rs = port^0;
 sbit rw = port^1;
 sbit e = port^2;
 sbit wr= port^3;
 sbit rd= port^4;
 sbit intr= port^5;
 int test_final=0 ,shift=0;
 void delay(unsigned int msec )
 {
 int i ,j ;
 for(i=0;i<msec;i++)
 for(j=0; j<1275; j++);
 }
 void lcd_cmd(unsigned char item) // Function to send command to LCD
 {
 dataport = item;
 rs= 0;
 rw=0;
 e=1;
 delay(1);
 e=0;
 return;
 }
 void lcd_data(unsigned char item) // Function to send data to LCD
 {
 dataport = item;
 rs= 1;
 rw=0;
 e=1;
 delay(1);

 e=0;
 return;
 }
 void lcd_data_string(unsigned char *str) // Function to send string to LCD
 {
 int i=0;
 while(str!='\0')
 {
 lcd_data(str);
 i++;
 delay(1);
 }
 return;
 }
 void convert()
 {
 int s;
 lcd_cmd(0x81);
 delay(2);
 lcd_data_string("output:");
 s=test_final/100;
 test_final=test_final%100;
 lcd_cmd(0x8a);
 if(s!=0)
 lcd_data(s+48);
 else
 lcd_cmd(0x06);
 s=test_final/10;
 test_final=test_final%10;
 lcd_data(s+48);
 lcd_data(test_final+48);
 lcd_data(' ');
 if(shift>16)
 {
 lcd_cmd(0xc0+(shift-1));
 lcd_data_string("       ");
 shift=0;
 }
 lcd_cmd(0xc0+(shift-1));
 lcd_data(' ');
 lcd_cmd(0xc0+shift);
 lcd_data_string("CALIBRATE IT");
 delay(30);
 }
 void main()
 {
 adc_input=0xff;
 lcd_cmd(0x38);  //2 Line, 5X7 Matrix
 lcd_cmd(0x0c);  //Display On, Cursor Blink
 delay(2);
 lcd_cmd(0x01);  // Clear Screen
 delay(2);
 lcd_cmd(0x81);
delay(2); 
 lcd_data_string(" start");
 delay(20);
 while(1)
 {
   shift++;
   delay(1);
   rd=1;
   wr=0;
   delay(1);
   wr=1;
   while(intr==1);
   rd=0;
   test_final=adc_input;
   delay(1);
   intr=1;
   convert();
 }
 }