Problem regarding with interfacing gsm module with Tiva c series launch pad

Hai

      currently i am working on TM4C123GH6PM micro controller,and here i have interfaced my micro controller to the GSM modem.And when i transmitting the command AT from my controller then it has to generate an interrupt in that interrupt handler i want to store only the "RESPONSE" of interrupt handler,but here i got the problem is the same data is also stored in side the buffer in the interrupt handler i.e what i send(same AT).......please help me about this issue.....thank u

here just i modified uart echo example....

 
#include <stdint.h> 
#include <stdbool.h> 
#include <string.h> 
#include "inc/tm4c123gh6pm.h" 
#include "inc/hw_ints.h" 
#include "inc/hw_memmap.h" 
#include "driverlib/debug.h" 
#include "driverlib/fpu.h" 
#include "driverlib/gpio.h" 
#include "driverlib/interrupt.h" 
#include "driverlib/pin_map.h" 
#include "driverlib/rom.h" 
#include "driverlib/sysctl.h" 
#include "driverlib/uart.h" 
#include "utils/uartstdio.h" 
#include "driverlib/uart.h" 
 
unsigned char ok[]="OK\r\n"; 
unsigned char m[20]; 
int count=0;
int count1=0; 
unsigned int i,j; 
 
 
// The error routine that is called if the driver library encounters an error. 
// 
//***************************************************************************** 
#ifdef DEBUG 
void 
__error__(char *pcFilename, uint32_t ui32Line) 
{ 
} 
#endif 
 
//***************************************************************************** 
 
// The UART interrupt handler. 
/************************************************************/ 
void 
UART1IntHandler(void) 
{ 
 
    uint32_t ui32Status;
    ++count1; 
 
 
 
    // 
    // Get the interrrupt status. 
    // 
    ui32Status = ROM_UARTIntStatus(UART1_BASE, true); 
 
    // 
    // Clear the asserted interrupts. 
 
            ROM_UARTIntClear(UART1_BASE, ui32Status); 
             
 
    // Loop while there are characters in the receive FIFO. 
    // 
 
 
    while(ROM_UARTCharsAvail(UART1_BASE)) 
    { 
      m[count]=ROM_UARTCharGetNonBlocking(UART1_BASE);
    
     count++;
     if(count==20);
     count=0; 
                
   } 
 
     ROM_IntDisable(INT_UART1); 
 } 
/********************************************************/ 
int 
main(void) 
{ 
    // 
    // Enable lazy stacking for interrupt handlers.  This allows floating-point 
    // //instructions to be used within interrupt handlers, but at the expense of 
    // extra stack usage. 
    // 
    ROM_FPUEnable(); 
    ROM_FPULazyStackingEnable(); 
 
    // 
    // Set the clocking to run directly from the crystal. 
    // 
    ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | 
                       SYSCTL_XTAL_16MHZ); 
 
   
     
 
    // 
    // Enable the peripherals used by this example. 
    // 
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART1); 
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); 
 
    // 
    // Enable processor interrupts. 
    // 
    ROM_IntMasterEnable(); 
 
    // 
    // Set GPIO B0 and B1 as UART pins. 
    // 
    GPIOPinConfigure(GPIO_PB0_U1RX); 
    GPIOPinConfigure(GPIO_PB1_U1TX); 
 
 
    ROM_GPIOPinTypeUART(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1); 
 
    // 
    // Configure the UART for 115,200, 8-N-1 operation. 
    // 
    ROM_UARTConfigSetExpClk(UART1_BASE, ROM_SysCtlClockGet(), 115200, 
                            (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | 
                             UART_CONFIG_PAR_NONE)); 
 
    // 
    // Enable the UART interrupt. 
 
    ROM_UARTIntEnable(UART1_BASE, UART_INT_RX | UART_INT_RT); 
 
    ROM_UARTFIFOEnable(UART1_BASE); 
 
    UARTFIFOLevelSet(UART1_BASE, UART_FIFO_TX1_8, UART_FIFO_RX1_8); 
 
    UARTEnable (UART1_BASE); 
 
    while(1) 
    { 
                   do 
                     { 
 
                        tx("AT\r\n"); 
 
                        SysCtlDelay(SysCtlClockGet()); 
                        SysCtlDelay(SysCtlClockGet()); 
                        SysCtlDelay(SysCtlClockGet()); 
                         
                 }while((strcmp(ok,m))!=0); 
 
                     
 
 
                       do 
                          { 
 
                                tx("AT+CREG=1\r\n"); 
 
                                SysCtlDelay(SysCtlClockGet()); 
                                SysCtlDelay(SysCtlClockGet()); 
                                SysCtlDelay(SysCtlClockGet());
 
                      }while((strcmp(ok,m))!=0); 
 
 
                      do 
                      { 
 
                                tx("AT+CREG=?\r\n"); 
 
                                SysCtlDelay(SysCtlClockGet()); 
                                SysCtlDelay(SysCtlClockGet()); 
                                SysCtlDelay(SysCtlClockGet());
 
                     }while((strcmp(ok,m))!=0);
 
         
  }
 
} 
void tx(unsigned char *p) 
{ 
    while(*p!='\0') 
    { 
        ROM_UARTCharPutNonBlocking(UART1_BASE, *p); 
            p++; 
    }

  ROM_IntEnable(INT_UART1); 
     
}