[Dspforum] bitrev_index

[Kyungjin Lim]

Yes, I was trying to follow the comments in the DSP Library to do outside of DSP. 
Thank you.
Regards,

Kayjin Lim

----- Original Message -----
From: Doug Wenstrand <doug at echelonembedded.com>
Date: Wednesday, October 14, 2009 12:25 pm
Subject: Re: [Dspforum] bitrev_index
To: dspforum at echelonembedded.com


> I think I'm answering your question, but if I misunderstood, please clarify:
> You are generating the table using the code provided.  You are able to 
> run
> it on the DSP, and it works, but you are trying to follow the comment 
> in
> the DSP library programmers reference which says : "this should be generated
> at compile time, not in the DSP"
> 
> That comment seems a little funny to me, because the function doesn't 
> care
> how that table got there, just that it is there.  In my opinion, the
> description of that function shouldn't give you general programming advice
> :) I suppose that the code for generating it will take up more space than
> the table itself, so it seems wasteful to generate it on board; 
> however you
> can go right ahead.
> 
> Again --
> 
> Go ahead and just make the index table on the DSP if you like.  Of course,
> _only make it once_, don't call it each time you call the bitrev function...
> that would be wasteful of clock cycles, which is what we really care about
> in this case
> 
> Now, if you wanted to export data in shorts, it is a little bit of a pain.
>  I often use hex, which makes it easier to parse the data later.  Still,
> like you point out, everything will come out in 32bit values, so you will
> have to do some post processing
> 
> 
> On Wed, Oct 14, 2009 at 11:22 AM, Kyungjin Lim <klim7 at jhu.edu> wrote:
> 
> > Hi
> >
> > I am having hard time to generate bitrev_index from C file provided.
> > However, DSP seems to be all right. What is the best way to convert 
> DSP
> > memory of short to C-array? File->Dada->Save doesn't have the option 
> for
> > short. I tried several of them, and none of the option preserved the 
> data
> > type.
> >
> > Thank you.
> >
> > Regards,
> >
> > Kayjin Lim
> >
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