Printing to the OF command line

Gabriel Paubert paubert at
Thu Apr 6 23:06:37 EST 2000

On Wed, 5 Apr 2000, Tom Gall wrote:

> Hi All,
>   This is an act of desperation on my part. But what the heck.
>   I'm trying to bring up a the 2.2.15pre14 kernel on an unsupported box.
> It's a 7043 43P 140 RS 6000. It's a labor of love.
>   Anyway, I've been having trouble even getting the kernel up any
> distance to even be able to puts to the screen. Something is dieing ...
> somewhere.
>   in arch/ppc/boot/of1275.c it would seem one should be able to perhaps
> open up some of device and print directly to the of command line without
> having to get into display adaptor issues. I would hope this would allow
> debugging in very difficult environments. (Which I'm in)

You don't even need to open it. Last time I successfully booted Linux on a
PreP machine with OF was early 96 (1.3.58 ?) so my memory is fuzzy. But
AFAIR I called the OF entry point with "interpret" command and executed
directly some string of Forth code.

>   Has anyone ever done this with this particular API? Is it even
> possible?

I think it is, and it's actually fairly simple. I could perhaps even find
it in my archives.


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