Alphan-
Sounds good that you made some progress. Yes I agree, if you have a lot of
existing big endian code, then being able
to re-use it with minimum effort could be helpful.
There is nothing fundamentally wrong with big endian code. The issues are
either a) access by an external entity, or
b) porting the code to a little endian device (for example, maybe in the future
you might run your DSP on an x86
server). I would say that if you can mark with comments or #ifdefs code
sections accessed (or likely to be accessed
in the future) by an external entity, then for now it's enough. Debugging
endian issues can be difficult; it helps if
you know where to look.
-Jeff
> Hello
> Firstly, I want to tell you that I am succeeded in running VCP2 in Big Endian
mode.
>
> Then Answer: We have 5-6 years of Big Endian experience on TI c64x and c64x+
DSPs, and also more on PowerPC CPUs in
> our department and it is very hard to quit old habits you know. In addition we
have some progress in our project and
> all the source codes are written in Big Endian. We have encountered some
problems regarding Endians so far and passed
> over some how. VCP2 is OK too now but we are losing time occasionally. Maybe
in later versions of design we will use a
> PowerPC CPU, but of course it is possible to use an endian conversion layer
for communication between them, it is not
> a fatal problem.
>
> Your Comment: We thought about switching to Little Endian but we decided to
move on in Big Endian mode. I am still
> considering about this issue, but I think we are using Big Endian mode, at
least for now.
>
> Thanks
> Alphan
> --- In c..., "Jeff Brower" wrote:
>>
>> Alphan-
>>
>> > I'm having trouble trying to run VCP2 on Big Endian Mode
>> > in a 6474 EVM. I'm working on an example project, which is
>> > working fine in Little Endian mode, the project gets data,
>> > convolutional encodes, expands bits to bytes, calculates
>> > branch metrics and setup VCP2. But I couldn't manage to
>> > get right results in Big Endian mode.
>> > Can anyone help me with this issue?
>>
>> Question: why do you need big endian mode? First, you already have
everything working in little endian mode.
>> Second, the only reason for big endian would be some type of system
interface, for example shared memory through an
>> FPGA or interface to another CPU or host processor. With the decline of
PowerPC, there are increasingly fewer
>> systems
>> that require a big-endian interface to the DSP.
>>
>> -Jeff
>
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