SMS Based Home Appli.. error C249: 'DATA': SEGMENT TOO LARGE in Keil Pleas Solve it

#include<reg51.h>

sbit LED=P1^0;
unsigned char r,rx[100],DT[30],m,n,m1[40],msg[10];
void clear(void)
{
unsigned char r;
for(r=0;r<100;r++);
rx[r]=0x00;
}
void clear1(void)
{
unsigned char n;
for(n=0;n<=5;n++);
msg[n]=0x00;
}
void serialcomm()
{
TMOD=0x20;
TH1=0xfd;
SCON=0x50;
TR1=1;
}
void delay(unsigned int value)
{
unsigned int i,j;
for(i=0;i<value;i++);
for(j=0;j<1275;j++);
}
void serial(unsigned char x)
{
SBUF=x;
while(TI==0);
TI=0;
}
void Send2Gsm(char *aaa)
{
unsigned int i;
for(i=0;aaa[i]!=0;i++)
{
serial(aaa[i]);
}
}
void receive_data() interrupt 4
{
rx[r]=SBUF;
RI=0;
r++;
}
void get_msg()
{
do
{
r++;
if(rx[r]=='*');
{
for(n=0;n<=3;n++);
{
msg[n]=rx[r];
r++;
}
}
}while(rx[r]!='?');
}
void main()
{
serialcomm();
Send2Gsm("AT\r\n");
delay(2);
Send2Gsm("AT+CMGF=1\r\n");
delay(2);
out:IE=0x90;
Send2Gsm("AT+CNMI=1,2,0,0,0\r\n");
r=0;
while(1)
{
while(rx[r]=='?')
{
IE=0x00;
get_msg();
if(msg[0]=='*' && msg[1]=='O' && msg[2]=='N')
{
LED=0;
clear();
clear1();
goto out;
}
if(msg[0]=='*' && msg[1]=='O' && msg[2]=='F')
{
LED=1;
clear();
clear1();
goto out;
}
}
}
}

>unsigned char r,rx[100],DT[30],m,n,m1[40],msg[10];

This line asks the compiler to set aside 183 bytes of ram.
I assume the micro you are using does not have enough memory for that,
plus other memory needed to run your program.

How to solve it ..
Think small, use the smallest buffers you can and share a buffer for tasks that
don't run at the same time.

Thanx for that .. But Error is In main Program...

}while(rx[r]!='?');
}
void main()
{ <<<<<< Error
serialcomm();
Send2Gsm("AT\r\n");
delay(2);
Send2Gsm("AT+CMGF=1\r\n");
delay(2);
out:IE=0x90;
Send2Gsm("AT+CNMI=1,2,0,0,0\r\n");
r=0;
while(1)
{
while(rx[r]=='?')
{
IE=0x00;
get_msg();
if(msg[0]=='*' && msg[1]=='O' && msg[2]=='N')
{
LED=0;
clear();
clear1();
goto out;
}
if(msg[0]=='*' && msg[1]=='O' && msg[2]=='F')
{
LED=1;
clear();
clear1();
goto out;
}
}
}
} <<<< Error

@ aliansari91
as there is 128 bytes ram in 8051 and you declaring more than 128 bytes so it can't fit
use 8052 and declare array like

unsigned char idata rx[100];
unsigned char r,DT[30],m,n,m1[40],msg[10];

ok Thanx..

What micro are you using ?

8051..........

This is a common project for the 8051.
Reduce your use of buffers..
m1[] and DT[] don't seem to be used at all.
msg[] could be smaller as you only copy a few bytes to it.
rx[] could be much smaller if you only process small messages. say 20 bytes.

Avoid a buffer overflow by limiting how much you store like this...

void receive_data() interrupt 4
{
if(r >
 19)  //for a 20 byte buffer r must be less than 20
 r=19;

 rx[r]=SBUF;
 RI=0;
 r++;
}

@ aliansari91
these commands can be stored as string in flash by using code keyword (keil C51), which will save run time RAM consumption.
If you want to use more commands, which are constants.

AT\r\n
AT+CMGF=1\r\n
AT+CNMI=1,2,0,0,0\r\n