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October 2009

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2009.10.07 19:25 "Wrong Native Bit Order on Intel x86_64", by Eskandar Ensafi
2009.10.07 19:59 "Re: Wrong Native Bit Order on Intel x86_64", by Bob Friesenhahn
2009.10.07 20:11 "Re: Wrong Native Bit Order on Intel x86_64", by Eskandar Ensafi
2009.10.07 20:24 "Re: Wrong Native Bit Order on Intel x86_64", by Toby Thain
2009.10.07 20:28 "Re: Wrong Native Bit Order on Intel x86_64", by Edward Lam
2009.10.07 21:26 "Re: Wrong Native Bit Order on Intel x86_64", by Bob Friesenhahn
2009.10.07 20:47 "Re: Wrong Native Bit Order on Intel x86_64", by Igor Skochinsky
2009.10.07 21:10 "Re: Wrong Native Bit Order on Intel x86_64", by Toby Thain
2009.10.07 20:17 "Re: Wrong Native Bit Order on Intel x86_64", by Bob Friesenhahn
2009.10.07 20:40 "Re: Wrong Native Bit Order on Intel x86_64", by Edward Lam
2009.10.07 21:43 "Re: Wrong Native Bit Order on Intel x86_64", by Bob Friesenhahn

2009.10.07 21:43 "Re: Wrong Native Bit Order on Intel x86_64", by Bob Friesenhahn

On Wed, 7 Oct 2009, Toby Thain wrote:
>
> As I understand it, the problem is not in the reading and writing code or 
> runtime behaviour, but relates to determination of the built default (May not 
> match platform's "actual" machine default.)
>
> The 'bug' would be at build-time, but it seems relatively unimportant to get 
> right, esp. for a C library.

I hope that you don't mind that I am Cc:ing this response to the list 
since it is an important issue to correct properly.

If the default is wrong, then the best-case penalty is that CPU is 
wasted executing TIFFReverseBits() when writing and reading files on 
the same system and the user explicitly specified the fill-order tag 
correctly for the CPU.  The worst-case penalty is that the files can't 
be read by some other host.  Since it took three years for this issue 
to be reported, the worst-case penalty seems unlikely since 
interoperability issues are noticed right away, and because no one has 
reported fill-order issues on unusual CPUs.

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/