Date   : Wed, 04 May 2005 21:07:14 +0100
From   : "Peter Edwards" <samwise@...>
Subject: Re: Chuckie Egg - better patch (and some mysteries solved!)

Rich,

> OK, it turns out there are certainly two different versions 
> of the Chuckie
> Egg executable around... they are mostly the same apart from 
> some changes
> of routine addresses in the critical place I'm patching (typical!).

Ahhh - maybe that explains why I was having trouble (off the list) with some
of David's pokes yesterday.  Curious - I had no idea there was more than one
version in the wild.

> The cheats from Peter Edwards don't seem to apply to the 
> StairwayToHell
> archive version 

> so I assume
> they're from the other version which is going around (Bill 
> says his is from
> the 'tosec' archives, whatever they are...),

Here i can help.  TOSEC stands for The Old School Emulation Center
[www.tosec.info].  This is an emulation group which has created a standard
naming convention
[http://www.romcenter.com/datafiles/tosec/tosec_naming_convention.htm] for
cataloguing old software.  It's a cross-platform endeavour, so isn't
restricted to just the beeb.  They are attempting to catalogue every piece
of software ever released and also hacks/variants for them.  You can
download the whole of their current bbc catalogue (up to version 0.35) by
searching on the eDonkey network for tosec+bbc ... as was detailed in an
earlier post to this list for access to the PD disks whilst 8bs is down.

This explains why both Bill and I had the same problems - as that's where I
sourced my versions of CE from, as well - their naming convention makes it
much easier to differentiate between the various hacks.

> and as I don't 
> have a copy of
> that version,

All the versions currently available on my site were sourced from TOSEC.
I'll soon be adding the alternate Stairway to Hell version!

> Anyway this explains the
> problems people have been having getting things to work correctly...

I had thought I was particularly unlucky considering the number of patches I
was messing up .. :)

> As an aside, I've noticed that the StairwayToHell version of 
> the game seems
> a little odd: upon completing a level, an extra life is 
> awarded, and then
> shortly taken away again.  This is not due to my patch - it 
> just seems to
> happen on the unpatched code.  Is this correct Chuckie Egg 
> behaviour?  Does
> the other version do this?

This sounds quite interesting.  Did you discover whether this happened in
the STH version?  (From now on I'll try to stick to calling them the STH
version and the TOSEC version!).  Is this related to the fact that when you
start a level you have say five lives ... and then Harry is placed on the
screen and the number of lives is reduced to four?  Is it perhaps just a
deliberate display thing?  If so, I assume that happens in both versions ...

> ...and now for anyone who's interested, here's how it all 
> works (long).

I'm considering collating all this kind of disassembled info that's been
provided to me by email since I raised this ... but with the addition of
multiple variants, I'm wondering if this is

a) worth it - as anyone who would be interested could probably figure it out
themselves (not me!)
b) out of my league .. !

hmm .. wonder if anyone else thinks its worth archiving?

> I found the other version of Chuckie Egg, so now we have a patch that
> should work well for all:

Ahh - I haven't tested it exhaustively, but it seems to work with the TOSEC
version at first glance!  :)

> Annoyingly, none of the pokes on Peter's Chuckie Egg page are 
> compatible
> with the StairwayToHell version either; they all need 
> slightly different
> addresses, i.e.:

Right.  I'll update my site with your new pokes for both versions
accordingly and add the STH version to the kit.

Hmm ... I could do with supplying a poke for ppl to identify the current
version (in case someone finds a file marked ce.ssd for example).  I think I
found the test in your listing, however I don't know which way round its
testing:

IF !&49AB=&202AD720
  PRINT "THIS IS STH";
ELSE
  PRINT "THIS IS TOSEC";

Is that right?  Or is it the other way round?

> [I don't think the 'infinite lives and invulnerability to 
> hens cheat works
> properly]

No, not properly - I'm hoping the poke after it will replace it ...

> Also, my suggestion for a slightly better speed control (both 
> versions):
> 
> *LOAD CH_EGG
> ?&1B20=<speed> (0=fast, 3=normal, 255=v slow!)
> CALL&29AB

I'll add this too .. :)
 
> The StairwayToHell version appears to be the slightly newer 
> one, containing
> a little bit of extra code... some kind of bugfix perhaps?
> 
> Rich

I'm quite intrigued by this ... how do you know its the newer one?  Cos it
has more code?  Any ideas what the new code actually does?

OK, well, I will up date my site tonight but it might not be until later -
I'll certainly make sure its done by tomorrow morning, tho ... and then I'll
spend some time tonight (maybe tomorrow morning) testing the pokes with the
two different versions.

Many thanks for the perseverence, Rich ... from what I've seen of your patch
it looks cool and can't wait to have a proper play with it later ... :)

Mail in a bit,

Peter.