util.c

   1 #include "util.h"
   2
   3 // bit population
   4 int bitpop(uint8_t bits)
   5 {
   6     int c;
   7     for (c = 0; bits; c++)
   8         bits &= bits -1;
   9     return c;
  10 }
  11
  12 // most significant on-bit
  13 int biton(uint8_t bits)
  14 {
  15     int n = 0;
  16     if (bits >> 4) { bits >>= 4; n += 4;}
  17     if (bits >> 2) { bits >>= 2; n += 2;}
  18     if (bits >> 1) { bits >>= 1; n += 1;}
  19     return n;
  20 }