MINSTREL_SCALE
val >>= MINSTREL_SCALE;
if (val > 1 << MINSTREL_SCALE)
val = 1 << MINSTREL_SCALE;
#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)