Date: Mon, 14 Jun 1993 14:13:23 -0700 (PDT)
From: [email protected]
To: [email protected]
Subject: Pac-Man Hack


       Before, I uploaded a hacked version of the Pac-Man game which allowed
it to be played on large (greater than 640x480) monitors. It was rejected, as
apparently software which has been modified by someone other than the author
is not allowed.
       So, I'm sending a textfile which allows the user to fix their own
copy. I decided to simplify the operation, and in doing so, I actually made
the hacked copy more secure! It will now only start in the "correct" situation,
that is, when it won't bomb or crash.
       This textfile carefully explains how to use ResEdit to get this game
to work on any monitor that Pac-Man will fit on. Have fun!
       (PS if you want to test it and make sure it works, Pac-Man is on
Sumex-aim.Stanford.Edu)
                                               *Stiles
`.`.`.``.`.`.`.`.`.`.`.`.`.`.`.`.`.CUT HERE.`.`.`.`.`.`.`.`.`.`.`.`.`.`.`.`.`.
Pac-Man Hack:

       This document shows a simple way to let M. Tsugi's "Pac-Man" game play
on many machines where it would not before. Currently, it only allows you to
play on a 640x480 size monitor, in 256 color resolution. Larger monitors would
not work, due to a minor bug in the program. This hack will work around that
bug, allowing you to play Pac-Man on any monitor 640x480 or bigger.

       If you are not comfortable with ResEdit�, please be cautious while
attempting this hack. If anything seems unfamiliar to you, try to get some help
performing this operation.

STEP 1: Make a backup copy.
**********      This is very important! Select Pacman and use "Duplicate" from
the Finder� File menu. If you mess up, you WILL destroy the game. **********

STEP 2: Open ResEdit.

STEP 3: Open Pac-Man inside ResEdit.
       You should get a nice-looking window showing all the resources within
       Pac-Man.

STEP 4: Double-click "CODE."
       Another window will open up, showing CODE 0, CODE 1, and CODE 2.

STEP 5: Double-click number 2.
       A window with lots of strange, hexadecimal numbers will appear.

STEP 6: Scroll down until the left-hand column reads 16F8.

STEP 7: Change the third byte in the row from 67 to 6C.
       Row 16F8 contains the hexadecimal numbers:
           EE2C 6710 A850 4267
       In the second block (6710), you need to change the 67 to 6C.

STEP 8: Save changes.
       Choose "Save" from ResEdit's File menu.

STEP 9: Quit ResEdit.
       You're done!

STEP 10:  Open Pac-Man and make sure that it works okay.
       If it bombs out, or crashes, or freezes, aren't you glad you kept that
back-up copy?

       This version will always do the "Right Thing" -- it won't play on a
monitor type it can't handle.

FOR THE TECHNICALLY INCLINED: The fix actually changes a comparison operation.
After the program tests if the monitor width is 640, the hack only changes a
BEQ.S (branch-if-equal) to a BGE.S (branch-if-greater-or-equal). Therefore, it
will work with all monitors greater than or equal to 640 pixels across, as
opposed to the earlier version only working with monitors exactly equal to 640
pixels across. For some reason, the vertical size of the monitor is never
checked.

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