uart help?

[Altera_Forum]

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;  }