Re: Apple IIgs Rom 0

[dempson@actrix.gen.nz (David Empson)]

Labelas Enoreth <labelas@hotmail.com> wrote:

> Hey, anyone out there who has access to a ROM 0 gs and has dumped the rom
> from it to a file?

I still have the ROM from when my machine was upgraded to a ROM 1, but
I'm not all that keen on putting it back in again (the machine and ROM
are at different locations, and I'd like to minimise wear and tear on
them).

> I'm interested in comparing it to a version 1.

I take you means a "browse" comparison, rather than a literal
byte-by-byte one?  The latter would be next to useless, since code is
likely to have moved around within the ROM, to some extent.  About the
only static part would be Applesoft BASIC, and some parts of the
$FF/F800-$FF/FFFF portion of the monitor.

There is a IIgs technical note that summarises the changes between ROM 0
and ROM 1, confusingly referring to the latter as "ROM 2.0".

> I have some monitor code to dump the rom from a v1, but I wasn't sure
> if any of the values were different in the v0.

Code?  We don't need no steenking code!

It is possible to dump the IIgs ROM 0 or ROM 1 to a file with a series
of four pairs of interleaved monitor memory move and BSAVE commands.
The required command sequence is identical for both ROM versions - you
are just saving memory contents, after all.

The ROM 3 needs twice as many commands, since the ROM is twice the size.

> Plus, the only person I know offhand with a Woz GS is covetous of it and
> keeps it in a box in their closet, so I don't think they'd be likely to
> let me boot it up and monkey with 'funny numbers that could hurt their
> computer'

Hurt their disk drive contents, maybe.  The computer itself is rather
hard to damage through software.  :-)

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand