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Lords of Conquest
https://atarimax.com/flashcart/forum/viewtopic.php?f=4&t=639
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Author:  Shawn Jefferson [ Sat Sep 08, 2007 1:12 am ]
Post subject:  Lords of Conquest

Here's Lords of Conquest for the 8Mb cart. The maps on the second disk work fine, but no saving has been implemented, so you can't save games, works or maps that you design.

Steve, when I was doing this I noticed that the version of multidsk.a65 that I have is missing a lda trig3 / sta gtintlk so it was causing the computer to freeze when turning the cart off. I wonder if I have the latest version of all the files? I don't remember having this issue with previous carts.

This game (and the pirate loader) makes several writes into D301, which is annoying... had to remove them. I also removed the two subroutines that display the "flip the disk and press the trigger" message and replaced them with code to change the disk unit number.

The subroutines were at $229C and $22AE and the new subs at those locations now modify $23ED which is loaded to DUNIT.

Author:  Shawn Jefferson [ Sun Sep 09, 2007 1:15 pm ]
Post subject: 

I looked at doing a few other multi-disk games, and it's interesting how many of them use their own SIO routines.

Seven Cities of Gold
221B Baker Street
Racing Destruction Set

All of them bypass the OS SIO routines and just use their own.

Bop n' Wrestle seems to be switching out the OS (?)

Anyway, these are all beyond my ability to put on flashcart. Maybe someone else will take a stab at them.

Author:  Wrathchild [ Sun Sep 09, 2007 4:45 pm ]
Post subject: 

SCoG seems a popular choice so I could give that
a go at some point, also Universe could be a good
choice for doing away with disk swap requests.

Regards,
Mark

Author:  Shawn Jefferson [ Mon Sep 10, 2007 9:07 pm ]
Post subject: 

I'd like to see Seven Cities of Gold, for sure. It definitely implements its own SIO routines, I guess so that it can dynamically load map sections during play ?

What's typically involved in ripping out the game's SIO routines? Would you put in calls to the OS routines, or just change the routine to load data from the flashcart directly (without a call to a modified $e456/9) ?

Author:  Wrathchild [ Tue Sep 11, 2007 3:51 am ]
Post subject: 

Hi Shawn,

With the Lucas games it was a case of locating where the
routines were in memory and determining how much of
it would become redundant and so could be over-written
by some new routines to replace sector load requests with
copy from flash code.

Once done I used a custom load routine to replace the
original such that, at the right point - normally after the
original code was loaded, the new routines would be
copied over the top. This I prefer rather than trying to
patch in new code into an existing game image.

This patching then may also extend to the original calls
to the load routines as the entry point typically has changed.

Similar stuff went on in Alternate Reality, but there are
more chained parts to the loader and there are a number
of load routines in these that each needed patching.

I posted some code on AtariAge for the Gauntlet cart,
that may give you some ideas:
http://www.atariage.com/forums/index.ph ... opic=67762

Regards,
Mark

PS: Games that write back to disk open another can of worms ;)

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