Function luaO_int2fb

lua/lobject.c:37–45

** converts an integer to a "floating point byte", represented as ** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if ** eeeee != 0 and (xxx) otherwise. */

** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb (unsigned int x) {
  int e = 0;  /* expoent */
  while (x >= 16) {
    x = (x+1) >> 1;
    e++;
  }
  if (x < 8) return x;
  else return ((e+1) << 3) | (cast_int(x) - 8);
}


/* converts back */