Subject: Re: booting ... loadbsd
To: Timothy Newsham <>
From: Eduardo E. Horvath <>
List: amiga
Date: 01/19/1995 09:05:19
On Tue, 17 Jan 1995, Timothy Newsham wrote:

> Hi,
>   I was just talking to someone who tried to load netbsd on his
> a1000 with 512k chipmem.  Of course it wouldnt work.  I am wondering
> what people think about putting more functionality in the loader
> to support more platforms.  In particular the loader could:
>     read amigados config information
>     read netbsd kernel
>     setup page tables to map fastmem to address zero
>     move kernel to fastmem
>     turn on MMU
>     jump to kernel
> the hard part comes with turning on the mmu.  The loader (actually
> just a small portion of the loader) would have to be relocated to
> another address that is valid before and after the mmu is turned
> on.  The benefits is the size of the kernel is no longer restricted
> by the size of chipmem.  

Actually, turning on the MMU is a bit of a problem.  A better solution 
would be to make everything through amiga_start() position independent 
code so the kernel never needs to be relocated.  Has anybody looked at 
gcc's PIC code generation?

> Another thing I would like for loadbsd is to be able to boot
> from 1.3.  I think the easiest way would be to modify loadbsd
> to be able to load and save configuration information.  When
> run with a certain flag it would read the config info from a file
> rather than through amigados 2.x calls.

I believe that everything loadbsd determines through poking around in the 
internals of AmigaOS can be superceded on the command line.  I think the 
primary reason for the 2.0 dependency is the ixemul.library.  One thing 
to seriously consider is translating loadbsd to assembly so we have finer 
control over AmigaOS library calls and version control, and so it could 
be compiled under NetBSD (I hate to maintain both a working BSD and 
AmigaOS compiler).  This could then be used as the basis of a bootblock 

But until then, I have other fish to fry.