Re: Custom boot loader stub

On Thu, 16 Oct 2025 11:44:30 +0200
Magnus Lindholm <[email protected]> wrote:

> On Wed, Oct 15, 2025 at 9:24 AM Sad Clouds <[email protected]> wrote:
> >
> > Hello, I'm attempting to design a small boot loader stub for sparc64
> > which can be loaded by OpenBoot and then it simply prints a test
> > message.
> >
> 
> Hi,
> 
> This is very interesting work! I was looking into something similar a
> while back, but on sparc32. Just for the fun of it.  I ended up working on
> some other project instead, but still, I would very much like it if you can
> share your progress somehow. Back in the days I was looking at how
> SILO did things on Linux/sparc32.
> 
> Regards
> 
> Magnus

As a hobby project, I would like to implement a small real-time kernel
for SPARC architecture. Getting the boot loader running is the first
step.

I'm struggling to find decent documentation which describes low-level
boot implementation for this architecture. I'm slowly getting there,
but digging through Illumos and NetBSD source code and figuring out for
example, disk label format and boot loader binary format is taking some
time.

I will document all this at some point, once I can get the basic boot
loader running and can print various machine registers on the console.