Re: [ECOS] IXP425 Big Endian Mode

[Sujoy Ray <raysujoy@yahoo.com>]

Hello Peter,

Thanks for your suggestion!

I am still having one doubt -

When I compare the code(pls read elf file) compiled in
little endian mode with the one in big endian mode
using objdump - I see that bytes are swapped. E.g a
code which looks like E6000021 in little endian mode
becomes 210000E6 in big endian mode. Now, during
instruction fetch and decode cycle, how processor
decodes this big endian instruction, when the state of
the processor is in little endian? Pls note that the
processor is in little endian mode and trying to
execute a big-endian instruction. So, byte 0 for it
will be E6 of the big endian instruction, but the
correct one should be 21. 

I think 'am confused in some way. Please help me to
come out from this confusion.

Regards,
Sujoy Ray.


--- Peter Korsgaard <jacmet@gmail.com> wrote:

> On 6/10/05, Sujoy Ray <raysujoy@yahoo.com> wrote:
> > big-endian order. Now, I have a question - how the
> > processor executes the above mentioned code, when
> it
> > is in little endian mode. I know for sure that
> there
> > is some way to do that because the code works
> fine. I
> > think 'am missing some basic concept - any
> suggestion
> > will be highly appreciated.
> 
> big/little endian mode only matters for 8 and 16bit
> accesses, and the
> instructions are 32bit.
> 
> See
>
http://www.intel.com/design/network/applnots/25423701.pdf
> for details.
> 
> -- 
> Bye, Peter Korsgaard
> 


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