u64_fill_right
c.bclr = ~u64_fill_right(c.umax);
c.bclr = ~u64_fill_right(c.umax);
c.bclr = ~u64_fill_right(c.umax);
c.bclr = ~u64_fill_right(c.umax);
c.bclr = ~u64_fill_right(c.umax);
c.bclr = ~u64_fill_right(c.umax);