Subject: Re: Boot ROM hacking
To: Andrew Gillham <gillhaa@ghost.whirlpool.com>
From: Simon Burge <simonb@netbsd.org>
List: port-i386
Date: 12/22/1999 23:25:17
Andrew Gillham wrote:

> With an approximately 8KB decompressor, there would be 24K of compressed
> space available, perhaps allowing 48K of code. (enough to have a ROM
> with CREAD support, etc all in 32K)

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
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...

Simon.