ps/2 mouse problem in nios system

Hi there!

I'm doing 1 small demo : detect the movement and button states from a ps2 mouse in nios system, I use the university IP core. nios build project no error, but when run, the console display nothing. Is the problem in read 3 byte (code c) or the printf function. Have you give me some advice or the code reference (read 3 byte from FIFO).

Thank!

the code below :

# include "altera_up_avalon_ps2.h"# include "altera_up_ps2_mouse.h"# include <alt_types.h># include <stdio.h># include <system.h>

int maxmin(int no, int max, int min)

{

if(no>max) {no=max;}

if(no<min) {no=min;}

return(no);

}

int main(void)

{

alt_up_ps2_dev * ps2_dev;

ps2_dev = alt_up_ps2_open_dev("/dev/ps2_0");

alt_up_ps2_init(ps2_dev);

alt_up_ps2_clear_fifo(ps2_dev);

unsigned char byte1, byte2, byte3, byte1_x, byte1_y;

alt_u8 X, Y, X1, Y1;

int pX=320, pY=240, B=0;

while(1)

{

alt_up_ps2_read_data_byte(ps2_dev, &byte1);//read 1 byte

alt_up_ps2_read_data_byte(ps2_dev, &byte2);

alt_up_ps2_read_data_byte(ps2_dev, &byte3);

byte1_x = byte1&0x10;

byte1_y = byte1&0x30;

B = (int)byte1&0x07;

if(byte1_x == 0)

{ X = byte2;

pX = pX + X;}

else

{ X1 = (~byte2) + 1;

pX = pX - X1;}

if(byte1_y == 0)

{ Y = byte3;

pY = pY + Y;}

else

{ Y1 = (~byte3) + 1;

pY = pY - Y1;}

pX=maxmin(pX,639,0);

pY=maxmin(pY,479,0);

printf("%d%d\n",pX,pY);

printf("%d\n",B ) ;

}

return 0;

}