COMBINE
#define COMBINE(a, b) (((u_int)(a) << HALF_BITS) | (b))
#define COMBINE(a, b) (((ulong_t)(a) << HALF_BITS) | (b))
#define COMBINE(hi, lo) (((uint64_t)(uint32_t)(hi) << 32) | (uint32_t)(lo))
#undef COMBINE /* local to previous routine */
#define COMBINE(hi, lo) (((uint64_t)(uint32_t)(hi) << 32) | (uint32_t)(lo))