SUM1
#define SUM1(i) sum += (u1 & mask) + (u1 >> 16)
#define SUM1(i) sum += u1
#define SUM1(i) sum += ptr[i]
#define SUM1(i) sum += *((uint16_t *)ptr)++; sum += *((uint16_t *)ptr)++
#define SUM1(i)
#undef SUM1