Please help me with my code. It does nothing when i burn the code into the AT89S52 mc.

#include <reg51.h>

void confirmPBready(void);
void BYTEwrite( unsigned char VAL, unsigned char buffLEN, unsigned char *buffADDR);
void sendAT(unsigned char *buf);
bit COMP_buff2buff( unsigned char *BUFF1, unsigned char *BUFF2, unsigned char LEN);
void delay(void);
bit OKay( unsigned char *BUFF1, unsigned char *BUFF2, unsigned char LEN);

unsigned char rcx[13];
code char txtMOD[]="AT+CMGF=1";
code char TE_com[]="AT+CSCS=\"GSM\"";
xdata unsigned char GSMRESPONSE[]="AT+CMGS=\"+2349056777712\"";
unsigned char respOK[] = "OK";
unsigned char PBcheck[]="+PBREADY";
bit RXDcmpt;
bit PBflag;
bit tr;
unsigned char  rxd_cnt = 0;
unsigned char SERIALcase ;
unsigned char *loc;




void main()
{
        //INITIALIZATION
        SCON = 0x50;
        TMOD = 0x20;
        TH1 = 0xFD;
        TR1 = 1;
        ES = 1;
        EA = 1;
        SERIALcase = 1;
        PBflag = rxd_cnt = RXDcmpt = 0;

        while(!PBflag)
        {
                if(RXDcmpt && !PBflag)
                confirmPBready();
        }

        BYTEwrite(0,sizeof(rcx),rcx);   //clear buffer

        sendAT(txtMOD);
        tr = OKay(rcx, respOK, sizeof(respOK));
        while(!tr);
        tr = 0;
        BYTEwrite(0,sizeof(rcx),rcx);


        sendAT(TE_com);
        tr = COMP_buff2buff(rcx, respOK, sizeof(respOK));
        while(!tr);
        tr = 0;
        BYTEwrite(0,sizeof(rcx),rcx);


                sendAT(GSMRESPONSE);
                delay();
                sendAT("GSM MODULE TEXT VIA CODING");
                delay();
                sendAT("0x1A");
}

void delay(void)
{
unsigned int i;
for(i=0;i<25000;i++);
}

void BYTEwrite( unsigned char VAL, unsigned char buffLEN, unsigned char *buffADDR)
{
while(buffLEN)
{
*buffADDR++ = VAL;
buffLEN--;
}
return;
}

bit COMP_buff2buff( unsigned char *BUFF1, unsigned char *BUFF2, unsigned char LEN)
{
LEN-=2;
while(LEN)
{
if(LEN ==2)
break;
if(*BUFF1++ != *BUFF2++)
return 0;

LEN--;
}
return 1;
}

void confirmPBready()
{
if( COMP_buff2buff(rcx , PBcheck, sizeof(PBcheck) ) )
PBflag = 1;
return;
}

void serial(void) interrupt 4
{
unsigned char RXD_VAL;
RXD_VAL = SBUF;

if(RI)
{
switch(SERIALcase)
{
case 1:
if(RXD_VAL == 0x0D)
{
SERIALcase=2;
}
break;
case 2:
if(RXD_VAL == 0x0A)
{
SERIALcase = 3;
}
break;
case 3:
if(RXD_VAL == 0x0D)
{
SERIALcase  = 4;
}
else
{
rcx[rxd_cnt++] = RXD_VAL;
}
break;
case 4:
if(RXD_VAL == 0x0A)
{
RXDcmpt = 1;

}
else
{
rcx[rxd_cnt++] = RXD_VAL;
}

SERIALcase  = 1;
break;
}
}
RI = 0;
}


void sendAT(unsigned char *buf)
{
        while(*buf)
        {
                SBUF = *buf++;
                while(!TI);
                TI=0;
        }
        SBUF = 0x0D;
        while(!TI);
        TI=0;
}

bit OKay( unsigned char *BUFF1, unsigned char *BUFF2, unsigned char LEN)
{
 while(LEN)
 {
  if(*BUFF1++ != *BUFF2++) //Check if both value in address are same.
   return 0;              //One value is different.
   LEN--;               //Decrement.
}
return 1;       //AT Last, all values are the same in both buffers.
}