Line data    Source code

       1             : #include <linux/kernel.h>
       2             : #include <asm/div64.h>
       3             : #include <linux/reciprocal_div.h>
       4             : #include <linux/export.h>
       5             : 
       6             : /*
       7             :  * For a description of the algorithm please have a look at
       8             :  * include/linux/reciprocal_div.h
       9             :  */
      10             : 
      11           0 : struct reciprocal_value reciprocal_value(u32 d)
      12             : {
      13             :         struct reciprocal_value R;
      14             :         u64 m;
      15             :         int l;
      16             : 
      17           0 :         l = fls(d - 1);
      18           0 :         m = ((1ULL << 32) * ((1ULL << l) - d));
      19           0 :         do_div(m, d);
      20           0 :         ++m;
      21           0 :         R.m = (u32)m;
      22           0 :         R.sh1 = min(l, 1);
      23           0 :         R.sh2 = max(l - 1, 0);
      24             : 
      25           0 :         return R;
      26             : }
      27             : EXPORT_SYMBOL(reciprocal_value);