[RESUBMIT] [PATCH] [MTD] NAND nand_ecc.c: rewrite for improved performance

Troy Kisky troy.kisky at boundarydevices.com
Mon Aug 18 13:20:51 EDT 2008


Frans Meulenbroeks wrote:
> Yes, the NSLU2 had a filesystem that was created before the patch was applied.
> But actually I think the filesystem is irrelevant.
> I verified the proper operation by comparing the values generated by
> the original code with the values generated by my code over a set of
> input blocks.
> Guess there is no endianness dependency and that if the data is big
> endian the ecc is too.
> 
> Frans.
> 

Does that make logical sense to you? The correction routine
accesses the data as a byte and flips a bit. If it accessed it as
an uint32 and flipped the bit, then I can see that there would be
no endianness dependency. I'm not suggesting you do that, as it would be
incompatible with current ecc, just explaining my logic. I'd very
much appreciate an explanation of why I'm wrong. I would expect
big endian ecc to have 4 bits differences whenever the entire
block parity is odd. These would be the bits that select the byte
within the uint32.

Troy




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