DS18b20 reading too high - 8051

//DS18B20 Code: DQ = P3.3
#include<intrins.h>
#include<AT89X51.H>
#include<math.h>
#include<stdio.h>


//LCD code: RS = P3.6 -- RW = P3.5 – E = P3.7 – DataLine = P1


sbit RS = P3^6; 
sbit RW = P3^5; 
sbit E = P3^7; 
sbit DQ = P0^1;

void init(void); 
void writeCmd( unsigned char a ); 
void writedat(unsigned char b );
void Delaylcd(void);
void sendstring(unsigned char *b);

void init() 
{ 
 	writeCmd(0x01);
 	writeCmd(0x38);
 	writeCmd(0x0C);
 	writeCmd(0x06);
}

void writeCmd(unsigned char a)
{
 	RS = 0;
 	P1 = a;
 	RW = 0;
 	E = 1;
 	Delaylcd(); 
 	E = 0;
}

void writedat(unsigned char b)
{
 	RS = 1;
 	P1 = b;
 	RW = 0;
 	E = 1;
 	Delaylcd(); 
 	E = 0;
}

void Delaylcd()
{
 	unsigned char j,k;
 	for (j=0; j<255; j++)
 	for (k=0; k<5; k++);
}

void sendstring(unsigned char *c)
{
 	while(*c) //till string ends
 	writedat(*c++); //send characters one by one
}







//sbit DQ=P3^3;
unsigned char tmp1, tmp2;
unsigned char buffer[16];
unsigned char cdis1[16] = {" TEMPERATURE: "};
unsigned char cdis2[16] = {"C"};

void delay(int useconds);
unsigned char ow_reset(void);
unsigned char read_bit(void);
void write_bit(char bitval);
unsigned char read_byte(void);
void write_byte(char val);
void get_temp(void);
float Temp_convert ();



void delay(int useconds)
{
 	int s;
 	for (s=0; s<useconds;s++);
}

unsigned char ow_reset(void)
{
 	unsigned char presence=0;
 	DQ = 0; //pull DQ line low
 	delay(29); // leave it low for 480us
 	DQ = 1; // allow line to return high
 	delay(3); // wait for presence
 	presence = DQ; // get presence signal
 	delay(25); // wait for end of timeslot
 	return(presence); // presence signal returned
} // 0=presence, 1 = no part 

unsigned char read_bit(void)
{
 	unsigned char i;
 	DQ = 0; // pull DQ low to start timeslot
 	DQ = 1; // then return high
 	for (i=0; i<3; i++); // delay 15us from start of timeslot
 	return(DQ); // return value of DQ line
}

void write_bit(char bitval)
{
 	DQ = 0; // pull DQ low to start timeslot
 	if(bitval==1)
	{
		DQ =1; // return DQ high if write 1
	}
 	delay(5); // hold value for remainder of timeslot
 	DQ = 1;
}


 
unsigned char read_byte(void)
{
 unsigned char i;
 unsigned char value = 0;
 	for (i=0;i<8;i++)
 	{
 	 if(read_bit())
	 {
		 value|=0x01<<i; // reads byte in, one byte at a time and then shifts it left.
		            	   // If DQ=0, skip, if DQ=1 execute shifting of "1" then OR.
	 }
 	 delay(6); // wait for rest of timeslot
 	}
return(value);
}// Delay provides 16us per loop, plus 24us. Therefore delay(5) = 104us

void write_byte(char val)
{
 	unsigned char i, temp2;
 	for (i=0; i<8; i++) // writes byte, one bit at a time
 	{
 		temp2 = val>>i; // shifts val right 'i' spaces
 		temp2 &= 0x01; // copy that bit to temp
 		write_bit(temp2); // write bit in temp into
 	}
 	delay(5);
}

void get_temp(void)
{ 
 	ow_reset();
 	write_byte(0xCC);
 	write_byte(0x44);
	delay(5);
 	ow_reset();
 	write_byte(0xCC);
 	write_byte(0xBE);
 	tmp1=read_byte();
 	tmp2=read_byte();
}

float Temp_convert ()
{
 	float f_temp1;
 	bit flag;
 	unsigned int uint_temp;
 	uint_temp=tmp2;
	uint_temp=uint_temp<<8;
 	uint_temp=uint_temp|tmp1;
 	flag=uint_temp&&0xF800;
 	
 	if(flag == 0xF800)
	{
 		f_temp1=(~uint_temp+1)*0.0625;
 		f_temp1= f_temp1*-1;
 	}
	
	else if(flag == 0)
 	{
 		f_temp1= uint_temp*0.0625;
 	}
  	return f_temp1;
}

void main()
{ 
	float f_temp2;
 	unsigned int uint_temp2;
	unsigned char j;
 	init();
 	writeCmd(0x80);
 	sendstring(cdis1);
 	writeCmd(0xCC); 
 	writedat(0xDF);
	writeCmd(0xCD);
	sendstring(cdis2);
 	

 	while(1)
 	{
 		get_temp();
	 	f_temp2= Temp_convert();
 	 	uint_temp2 = f_temp2 * 100;
 	 	sprintf(buffer,"%3d.%2d",uint_temp2/100,uint_temp2%100);
		//sprintf(buffer,"%3.4f\r\n",f_temp2);
		writeCmd(0xC2);
 	 	sendstring(buffer);
 		for(j=0; j<1000; j++);
 	 	uint_temp2=0x00;
 	}
}

while(1)
 	{
 		get_temp();
	 	f_temp2= Temp_convert();
 	 	uint_temp2 = f_temp2 * 100;
		sprintf(buffer,"t2=%x",tmp2);
		writeCmd(0xC0);
 	 	sendstring(buffer);
		sprintf(buffer," t1=%x",tmp1);
 	 	sendstring(buffer);
 		for(j=0; j<1000; j++);
 	 	uint_temp2=0x00;
 	}

http://www.maximintegrated.com/app-notes/index.mvp/id/162

void get_temp(void)
{ 
 	ow_reset();
 	write_byte(0xCC);  // Skip ROM
 	write_byte(0x44);  // Start Conversion
	delay(5);
 	ow_reset();
 	write_byte(0xCC);  // Skip ROM
 	write_byte(0xBE);  // Read Scratch Pad
 	tmp1=read_byte();
 	tmp2=read_byte();
}

void Read_ROMCode(void)
{
int n;
char dat[9];
sendstring(buffer);
ow_reset();
write_byte(0x33);
for (n=0;n<8;n++){dat[n]=read_byte();}
sprintf(buffer,"\n%X%X%X%X\n",dat[7],dat[6],dat[5],dat[4],dat[3],dat[2],dat[1],dat[0]);
sendstring(buffer);
}

unsigned char cdis1[16] = {" OK "};
unsigned char cdis2[16] = {" Fail "};
void main()
{ 
	unsigned char chk=0;
	unsigned char j;
 	init();

 	while(1)
 	{
		writeCmd(0xC0);
		chk=ow_reset();
		if(!xchk)
		{
			sendstring(cdis1);
		}
		else
		{
			sendstring(cdis2);
		}
 		for(j=0; j<1000; j++);
 	}
}

		ow_reset();
		write_byte(0xCC); //Skip ROM
		write_byte(0x44); // Start Conversion
		delay(5);
		ow_reset();
		write_byte(0xCC);  // Read Scratch Pad
		Read_ScratchPad();

void Read_ScratchPad(void)
{
	int j;
	char pad[10];
	write_byte(0xBE);
	for (j=0;j<9;j++){pad[j]=read_byte();}
	sprintf(buffer,"%X%X",pad[1],pad[0]);
	sendstring(buffer);
}