Re: [[oc] Huffman coding]

[Richard Herveille <richard@asics.ws>]

On Friday 25 October 2002 15:16, John Sheahan wrote:
> > For decoding:
> > I receive a bitstream and I need to match the incomming variable
> > huffman-code with an address. The more I think about it, the more I am
> > pushed to a CAM. Anybody any suggestions how to code a CAM in HDL?? Or do
> > you have a better suggestion.
>
> A cam is usually implemented as a bank of XOR gates between the data in
> and the registers of a ram.
> That XOR tree and something to force the data on hit is pretty messy -
> bigger than the data storage.
>
> for many cam applications - its better to prearrange the data in a ram and
> look it up directly by address.  I would have thought that would fit here
> actually.

Isn't that a waiste of memory when I use the huffman-coded result to find the 
original data. For example, the huffman code can be 16bits wide, to do 
reverse lookup I would need a memory with a 16bit addressbus to store say 256 
results.

>
> or sort the data in the ram and do a binary search on contents. with a
> few more bits to store the key.

Hmm this sounds interresting. Any pointers??

>
> john

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