Re: Prince of Persia Source Code - Found!

[BLuRry <brendan.robert@gmail.com>]

I disagree.  Yes, you can get information about the eggs from the internet.  But most of the information is about the PC port.  Second, the code is the best resource of information for how the game works.

As pointed out before, most of the game lives in the AUX ram.  After studying the gameeq.s, I found out it was very easy to train this game in JACE.  So I did, and I'm going to finally do something in JACE that it was designed to do originally: Add cheats.

Feather Fall: Hold the CharYVel variable (0x48) at 1 if it is anything other than zero (which indicates the Prince is on the ground).  This causes a feather fall.

Infinite life: Works great, but will cause crashes if you run over a spike.  (memory address 0x0ce)

Sleepy Time: Causes enemies to not react at all.  They just stand there and you can walk right past them (memory address 0x0d1, hold at value 0)

Infinite Time: Keeps timer at 69 minutes.  (memory address 0x0300)

FUN!!!  I love reading other peoples' code.   Other cheats are possible.  It could also be possible to make the prince jump further and all other kinds of crazy stuff.  Since I could read the movement logic and see how it interacted with the ZP registers, I could even concoct a warp jump feature.  I probably won't, but I think I know how to at least.

-B

On Tuesday, April 17, 2012 4:15:03 PM UTC-5, Helpful Harry wrote:
> In article
> <20716195.2665.1334676175538.JavaMail.geo-discussion-forums@ynjm4>, BLuRry
> 
>  wrote:
> 
> > On Tuesday, April 17, 2012 9:45:10 AM UTC-5, N.N. Thayer wrote:
> > > The code has been posted at GitHub:
> > > 
> > > https://github.com/jmechner/Prince-of-Persia-Apple-II
> > > 
> > > Jason Scott's guest post on Mechner's blog:
> > > 
> > > http://jordanmechner.com/blog/2012/04/textfiles/
> > 
> > Yessss!  Found the Boot0 easter eggs in the source.  It's a lookup 
> > table listing each key and its corresponding address to JMP to.   
> > I wonder what confusion does?
> > 
> > :dispatch hex FF
> >  da oscsh
> > 
> >  asc "!"
> >  da rcmess
> > 
> >  hex 8D
> >  da confusion
> > 
> >  asc "@"
> >  da rotcube
> > 
> >  asc "^"
> >  da drive
> 
> 
> It's much easier to find the easter egg / cheat codes via an Internet search.
> 
> From memory, "confusion" makes the enemies easier to kill (they are
> confused and don't fight as well as normal).
> 
> Helpful Harry   :o)