Subversion Repositories planix.SVN

#include "os.h"
#include <libsec.h>

#define Maxrand ((1UL<<31)-1)

ulong
nfastrand(ulong n)
{
        ulong m, r;
        
        /*
         * set m to the maximum multiple of n <= 2^31-1
         * so we want a random number < m.
         */
        if(n > Maxrand)
                sysfatal("nfastrand: n too large");

        m = Maxrand - Maxrand % n;
        while((r = fastrand()) >= m)
                ;
        return r%n;
}