Linux

   expires_limit = 0x20000000e
   bit = 33
   mask = (1 << 33) - 1  /* undefined */

   static inline`enter code here`
     unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
    {
         unsigned long expires_limit, mask;
         int bit;
 
         if (timer->slack >= 0) {`enter code here`
                 expires_limit = expires + timer->slack;
         } else {
                 long delta = expires - jiffies;
 
                 if (delta < 256)
                         return expires;
 
                expires_limit = expires + delta / 256;
         }
         mask = expires ^ expires_limit;
         if (mask == 0)
                 return expires;
 
         bit = find_last_bit(&mask, BITS_PER_LONG);
 
         mask = (1 << bit) - 1;

          expires_limit = expires_limit & ~(mask);
         return expires_limit;
    }