Subject: Re: Boot ROM hacking
To: Simon Burge <simonb@NetBSD.ORG>
From: Andrew Gillham <gillhaa@ghost.whirlpool.com>
List: port-i386
Date: 12/22/1999 11:49:19
Simon Burge writes:
> 
> Look at minilzo (http://wildsau.idv.uni-linz.ac.at/mfx/lzo.html).  On
> an i386:
> 
> 	wincen:~/zz/minilzo.106 49> size minilzo.o testmini 
> 	text    data    bss     dec     hex     filename
> 	4161    8       12      4181    1055    minilzo.o
> 	7323    264     197684  205271  321d7   testmini
> 
> 
> That 4.1k is both the compressor and decompressor!  "testmini" is

Awesome!  I'll check this out.  Perhaps it might be possible to build
a shim package that takes an existing netboot.rom and creates the minilzo
version. :-)  I suppose the relocating would need to be fixed up though,
because if the minilzo relocated/decompressed into 9000:0, it wouldn't
work to have start_rom.S relocate again. (unless it checks for it's proper
location?  I'll have to look)

> a harness for testing.  Modified to read in the first 32k of my
> netboot.com (the balance of the 64k is zeros) I get:
> 
> 	wincen:~/zz/minilzo.106 47> ./testmini
> 
> 	LZO real-time data compression library (v1.06, Nov 29 1999).
> 	Copyright (C) 1996, 1997, 1998 Markus Franz Xaver Johannes Oberhumer
> 
> 	compressed 65536 bytes into 20896 bytes
> 	decompressed 20896 bytes back into 65536 bytes
> 
> So perhaps this could be worth looking into further...

Definitely!

Thanks for the pointer.

-Andrew
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