I2_BITS
struct sw842_hlist_node2 node2[1 << I2_BITS];
ret = add_bits(p, p->index2[b >> 1], I2_BITS);
u64 n2 = (pos >> 1) % (1 << I2_BITS);
#define I2_FIFO_SIZE (2 * (1 << I2_BITS))
return __do_index(p, 2, I2_BITS, I2_FIFO_SIZE);