driver-api/mtd/nand_ecc.rst

554         cur = *bp++; tmppar  = cur; rp4 ^= cur;
555         cur = *bp++; tmppar ^= cur; rp6 ^= tmppar;
556         cur = *bp++; tmppar ^= cur; rp4 ^= cur;
557         cur = *bp++; tmppar ^= cur; rp8 ^= tmppar;
559         cur = *bp++; tmppar ^= cur; rp4 ^= cur; rp6 ^= cur;
560         cur = *bp++; tmppar ^= cur; rp6 ^= cur;
561         cur = *bp++; tmppar ^= cur; rp4 ^= cur;
562         cur = *bp++; tmppar ^= cur; rp10 ^= tmppar;
564         cur = *bp++; tmppar ^= cur; rp4 ^= cur; rp6 ^= cur; rp8 ^= cur;
565         cur = *bp++; tmppar ^= cur; rp6 ^= cur; rp8 ^= cur;
566         cur = *bp++; tmppar ^= cur; rp4 ^= cur; rp8 ^= cur;
567         cur = *bp++; tmppar ^= cur; rp8 ^= cur;
569         cur = *bp++; tmppar ^= cur; rp4 ^= cur; rp6 ^= cur;
570         cur = *bp++; tmppar ^= cur; rp6 ^= cur;
571         cur = *bp++; tmppar ^= cur; rp4 ^= cur;
572         cur = *bp++; tmppar ^= cur;
574         par ^= tmppar;
575         if ((i & 0x1) == 0) rp12 ^= tmppar;
576         if ((i & 0x2) == 0) rp14 ^= tmppar;
579 As you can see tmppar is used to accumulate the parity within a for
583 While making the changes I also found that I could exploit that tmppar
586 I removed the rp6 ^= cur; statement and did rp6 ^= tmppar; on next
613 encoded slightly more efficiently by saving tmppar before those 4 lines
614 and later do rp8 = rp8 ^ tmppar ^ notrp8;
627         cur = *bp++; tmppar  = cur; rp4 ^= cur;
628         cur = *bp++; tmppar ^= cur; rp6 ^= tmppar;
629         cur = *bp++; tmppar ^= cur; rp4 ^= cur;
630         cur = *bp++; tmppar ^= cur; rp8 ^= tmppar;
632         cur = *bp++; tmppar ^= cur; rp4_6 ^= cur;
633         cur = *bp++; tmppar ^= cur; rp6 ^= cur;
634         cur = *bp++; tmppar ^= cur; rp4 ^= cur;
635         cur = *bp++; tmppar ^= cur; rp10 ^= tmppar;
637         notrp8 = tmppar;
638         cur = *bp++; tmppar ^= cur; rp4_6 ^= cur;
639         cur = *bp++; tmppar ^= cur; rp6 ^= cur;
640         cur = *bp++; tmppar ^= cur; rp4 ^= cur;
641         cur = *bp++; tmppar ^= cur;
642         rp8 = rp8 ^ tmppar ^ notrp8;
644         cur = *bp++; tmppar ^= cur; rp4_6 ^= cur;
645         cur = *bp++; tmppar ^= cur; rp6 ^= cur;
646         cur = *bp++; tmppar ^= cur; rp4 ^= cur;
647         cur = *bp++; tmppar ^= cur;
649         par ^= tmppar;
650         if ((i & 0x1) == 0) rp12 ^= tmppar;
651         if ((i & 0x2) == 0) rp14 ^= tmppar;