Re: Scripting DDB in Forth?

[Eduardo Horvath <eeh%NetBSD.org@localhost>]

On Mon, 2 May 2016, Valery Ushakov wrote:

> On Mon, May 02, 2016 at 00:59:06 -0400, Michael wrote:
> 
> > On Mon, 2 May 2016 04:59:32 +0300
> > Valery Ushakov <uwe%stderr.spb.ru@localhost> wrote:

> > > I thought it might be interesting to put it into the kernel so that
> > > it can be hooked into DDB.
> > 
> > I'm afraid my first thought was OF_interpret() on machines that have
> > OF-like device trees but no OF.
> 
> I'm not sure I understand.  OF_interpret() by itself is not that
> useful unless you have the real OF device tree you can talk to.  But
> if you don't care about the abstraction / OOP layer of OF and just
> need ability to execute some code dynamically, then I don't see why
> not.

You can use OF_interpret() to access the underlying Forth engine for for 
firmware that has it.  However nowadays IEEE-1275 device trees are use by 
firmware written in C without Forth engines.  Of course the problem with 
that is once the OS boots the ability of the firmware to allocate memory 
is severely limited.

> Or we can port real OF perhaps?  OpenBIOS is GPLv2, but since it will
> not be part of the kernel, that's not an issue.  Also, Sun did release
> OpenBOOT under BSD'ish license, if you want to be a purist about the
> licensing and don't mind doing extra work.

OpenBOOT is very SPARC-centric.  There's lots of SPARC assembly code 
throughout.

Firmworks put together Open Firmware, which is an IEEE-1275 implemenation 
released under a BSD license, but last time I looked it seemed mostly 
focused on ARM CPUs.

As far as that goes, about 10 years ago I threw together an IEEE-1275 
implementation based on the pForth engine.  Since the kernel is written in 
C, it's more easily portable.  I probably have the code lying around 
somewhere.

Eduardo