compression

[jok]

Anyone ever port a data compression/decompression routine to an embedded
application?

-Jim

[Douglas Jerome]

I don't know if this is the right thing, but you might try
the code at http://www.imatix.com/html/sfl/index.htm

--
Douglas Jerome
http://www.primenet.com/~jerome

[Jack Klein]

On Tue, 7 Sep 1999 21:26:39 -0400, "jok" <j...@erols.com> wrote in
comp.arch.embedded:

> Anyone ever port a data compression/decompression routine to an embedded
> application?
>
> -Jim

I did a send only fax machine on an ASIC that emulated half of the
Intel X86 80x96 instruction set. That did the standard Group 3 fax
compression on rows of pixel data. Since it didn't receive faxes or
print images I didn't implement the decompression half, but I did it
on a PC for testing over a serial line before the MODEM was working.

Exactly what kind of compression are you talking about?

Jack Klein
--
Home: http://home.att.net/~jackklein

[jok]

Looking at the classical zlib, which is used in gzip and gunzip. Just
trying to understand a good approach in assembly code. It looks like making
binary trees is a critical item and then being able to search them and
modify them also. There is C code, just was looking for any assembly code
that might have this type of data structure/search routines.

Thanks.

Jim

Jack Klein wrote in message <37d9c459...@netnews.worldnet.att.net>...

[Steve Rencontre]

On Tue, 7 Sep 1999 21:26:39 -0400, in
<7r4dbr$kha$1...@winter.news.rcn.net> "jok" <j...@erols.com> wrote:

>Anyone ever port a data compression/decompression routine to an embedded
>application?

Yes. Next question?
--
Steve Rencontre, Design Consultant
http://www.rsn-tech.demon.co.uk/ -- remember to despam return address

[42ba...@my-deja.com]

In article <7r4dbr$kha$1...@winter.news.rcn.net>,

"jok" <j...@erols.com> wrote:
> Anyone ever port a data compression/decompression routine to an
embedded
> application?

Yes. LZ77 decrompressor in 65C02 ! Fast depack, good compression minimal
memory (RAM) required.
Ah, and a arj-depacker (method 4)....

-
42Bastian

Now my question: Anyone ever port a Mandelbrot-generator to embedded ?
:-)))
(Sorry could not resist, next time you should be more specific !)

Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

[jok]

Sorry about being non-specific. I am actually looking at porting the LZ77
algorithm to an embedded system. More than that it is actually the deflate
specification which is the compressed format used in the ZLIB library.

Making my way through the code and also reading up on the algorithm.

Was looking to see if any caveats or suggestions could be shared from those
who may have done this before.

Thanks.

Regards,

Jim
42ba...@my-deja.com <42ba...@my-deja.com> wrote in message
<7r7ju5$q4j$1...@nnrp1.deja.com>...

[jok]

Looking at the ZLIB library. Trying to find some assembly code examples of
algorithm on any processor.

Jim

Jack Klein wrote in message <37d9c459...@netnews.worldnet.att.net>...
>On Tue, 7 Sep 1999 21:26:39 -0400, "jok" <j...@erols.com> wrote in
>comp.arch.embedded:
>

>> Anyone ever port a data compression/decompression routine to an embedded
>> application?
>>

[Alexander]

Hi!

Douglas Jerome пишет в сообщении <37D5E935...@primenet.com> ...

>jok wrote:
>>
>> Anyone ever port a data compression/decompression routine to an embedded
>> application?
>>
>> -Jim
>

>I don't know if this is the right thing, but you might try
>the code at http://www.imatix.com/html/sfl/index.htm
>

Yes, this is great things, but can anybody explain me what doing this
function:

if (get_match (src, src_index, src_size,
Hash, &Size, &SymbolAddress) != 0)

function get_match have as arguments 3 word and 3 pointer.

Alex Gaivoronsky,
Motorola, Moscow.

[jok]

We should post that and related code on the learning C newsgroup.

Jim

Alexander wrote in message <7s0ifg$b5$1...@ns.mtu.ru>...

[jok]

What type of benchmarks did you obtain for the port you did to 65c02?
Did you use any of the Huffman trees to compress the LZ77 further?
What was your window size?

Thanks.

Regards,

Jim
42ba...@my-deja.com <42ba...@my-deja.com> wrote in message
<7r7ju5$q4j$1...@nnrp1.deja.com>...
>In article <7r4dbr$kha$1...@winter.news.rcn.net>,

> "jok" <j...@erols.com> wrote:
>> Anyone ever port a data compression/decompression routine to an
>embedded
>> application?

[d_c...@my-deja.com]

Dear Jok,

I've been collecting some short and simple data compression ideas at
http://www.rdrop.com/~cary/html/data_compression.html#short
.

TurboPacker
http://www.geocities.com/SiliconValley/Byte/4242/lynx/tools.html
(a LZ packer) supposedly runs quite fast for a 65c02.

What are you trying to compress and decompress ? Messages in some
natural language ? One large binary executable ? Pictures for a LCD
display ? Or some predefined compressed communications protocol ?

If you find any more ideas for data compression on embedded systems,
please let me know so I can add them to my web page.

If you have some C compression code and just want to see how it is
implemented in assembly language, just run it through GCC and add the
-S -fverbose-asm
options to create human-readable assembly language output. I imagine
you'll also want to try the -Os (optimize for size, rather than speed)
option. I assume you have targeted GCC for your favorite assembly
language.