random number generator?

Hi I am new to nios ii and was wondering if there was a random number generator. I have been try to use rand(), but it seems to only return 0s. I was wondering if I was doing something wrong. Could someone explain what libraries I should include? These are the libraries I am using thus far:

# include "alt_types.h"

# include "altera_avalon_pio_regs.h"

# include "alt_ucosii_simple_error_check.h"

# include <stdlib.h>

# include <stdio.h>

# include <system.h>

# include <sys/time.h>

# include <sys/alt_timestamp.h>