UINT16BYTES
UINT16BYTES(pfat32_bsbpb->BPB_RsvdSecCnt) +
fat_BytesPerSector = UINT16BYTES(pfat32_bsbpb->BPB_BytsPerSec);
if (UINT16BYTES(pfat_bsbpb->BPB_FATSz16) != 0) {