uart help?

hardware:apex20K200E

software:quartus+sp1+nios

I want to receive the message access the uart .The information is attained by Simense GSM module.Please correct the code as follows:

//

//#include "buffer.h" // defines RXBUFSIZE and TXBUFSIZE# include <stdio.h># include "excalibur.h"# include "nios.h"

# define RXBUFSIZE 256

//#define TXBUFSIZE 256

//Global variables

unsigned char RxBuf[RXBUFSIZE]; // the receiver buffer.

int RxHead = 0; // the circular buffer index

int RxTail = 0;

//unsigned char TxBuf[TXBUFSIZE]; // the transmit buffer.

//int TxHead = 0; // the circular buffer index

//int TxTail = 0;

void simpleReceiver1(int context);

unsigned char _getchar();

void MyPIO_ISR(int context);

int main(void)

{

int context = 0;

int bidir_port_to_and_from_the_led_pio[1];

unsigned char rxchar;

np_pio *pio = na_led_pio;

nr_installuserisr(na_uart1_irq, simpleReceiver1, context); // install UART ISR (receiver)

na_uart1->np_uartcontrol = np_uartcontrol_irrdy_mask; // enable rrdy interrupt

while(1)

{

rxchar = _getchar();

printf("\nfrom RxBuf: %c \n",rxchar);

nr_installuserisr(na_button_pio_irq,MyPIO_ISR,(int)pio);

pio->np_pioedgecapture = 0; // clear any existing IRQ condition

pio->np_piodirection = 0; // all input

pio->np_piointerruptmask = 0xff; // they all generate irq&#39;s!

// bidir_port_to_and_from_the_led_pio[1]=1;

}

return 0;

}

// pass an int to make it compatible with nr_installuserisr2 routine

// contents of third argument ("context") in nr_installuserisr is passed to ISR

void simpleReceiver1(int data)

{

// put new char into buffer from UART

RxBuf[RxHead] = na_uart1->np_uartrxdata;

// clear the errors and interrupts

na_uart1->np_uartstatus=0;

if ((++RxHead) > (RXBUFSIZE-1))

{

RxHead = 0;

}

}

//receive _getchar

unsigned char _getchar()

{

//Global variables

//unsigned char RxBuf[RXBUFSIZE]; // the receiver buffer.

//int RxHead; // the circular buffer index

//int RxTail;

unsigned char temp;

while (RxTail == RxHead)

{

nr_delay(1);

}

temp = RxBuf[RxTail];

if (++RxTail > (RXBUFSIZE -1))

{

RxTail = 0;

}

return(temp);

}

void MyPIO_ISR(int context)

{

int bidir_port_to_and_from_the_led_pio[1];

np_pio *pio = (np_pio *)context;

char s[256]; // a string

pio->np_pioedgecapture = 0; // clear the irq condition

bidir_port_to_and_from_the_led_pio[1]=1;

}