+ buf_64 ++;
+ }
+
+ if (len % sizeof(uint64_t)) {
+ /* If the buffer is not aligned to 64-bit, we need
+ to zero-pad the last few bytes and add them in */
+ uint64_t buf_tail = 0;
+
+ memcpy(&buf_tail, buf_64, len % sizeof(uint64_t));
+
+ sum += buf_tail;
+ if (sum < buf_tail)
+ /* wrap around */
+ sum++;