[TriLUG] An Apple Puzzle

[Greg Brown]

This is a Geocache puzzle and relates to old Apple II machines.  I don't
know assembly language hence I wanted to ask you all.

*Apple ][ Forever! GC1P5DQ*

*N 33° 29.900 W 112° 00.250*

A blast from the past.

A very special puzzle cache. The coordinates listed are NOT the actual
location of the cache. They will leave you about a block away from the
actual cache location. Finding the cache requires access to an Apple ][ home
computer system (one of the originals sold in the late 70's or early 80s)
and a knowledge of 6502 Assembly language.

NOTE: If you are an embedded systems designer with sufficient knowledge and
experience with other 8-bit assembly languages, you may download data sheets
for the 6502 and cross-reference the machine code by hand- in this case, no
Apple ][ is necessary.

Anyway, let's get down to business. Turn on your Apple and find your way to
the Applesoft "]" prompt. Enter the following commands:

CALL -151
300:A0 00 B9 11 03 F0 09 20 ED FD C8 E8 C8 4C 02 03
310:60 B3 B8
B2 B3 B0 CA CE D3 D7 B2 B6 B5 B9 B9 B4
320:AE C0 B6 B9 B0 B9 B2 B1 B6 B4 B2
B3 AC AE B9 B1
330:B1 B9 B1 B5 B4 B2 B2 D1 D7 C5 D3 B0 B1 B4 B0 B0
340:B8 AE
AE B5 B1 B3 B4 B7 B6 B5 B3 B0 B9 AC B2 B3
350:C2 D3 C4 C1 D7 C5 C3 C2 D6 CB
CC CC A0 B4 CE D0
360:C1 D2 C1 D5 D9 D4 C3 C6 C9 AC B9 CF 00 00 00 00
300G

Gibberish, no? There is a minor bug in this program. Can you spot it? I will
give you a hint: We have no need to use the "X" register for anything. One
of the machine instructions needs to be replaced with the identical
instruction that acts on the "Y" register instead.. so come on, all you
Apple hax0rz out there, figure it out.

Cache container: contains a logsheet and a pencil, and has room for a few
more items. For those of you who have experience with these things, you will
note that a special tool is often needed to open it. I have modified it to
make it easy to open. Just lift the top straight up off the base, no
twisting or bending needed. And, once again, apologies to anybody who came
by today (3/26/09) and DNF. It took me a little longer than expected to
secure this very unique cache container.

Congratulations to Team AZFastFeet for the FTF!

UPDATE 4/18/09: Raised difficulty from 4.5 back up to 5 stars due to such
few attempts on this cache. Also added a couple of hints to help with the
physical hunt on-site. With a ration of common sense and a properly-solved
puzzle, you will not need to look at the encrypted hints.



 *Additional Hints (*
*Encrypt*<http://www.geocaching.com/seek/cache_details.aspx?pf=&guid=038bed06-ed5c-473f-b585-46c72e8b23ee&decrypt=&log=&numlogs=>
*)*


 No hints will be given for the puzzle itself. The puzzle accounts for 99%
of what warrants this cache a 5-star difficulty. You will either know what
to do, or you wont.

Cache is not inside of any occupied structure, not in any shed, utility
building, etc., and not inside of a vehicle. There is no reason to knock on
any doors or trespass on neighbor muggles' private property. The message in
the puzzle will tell you exactly where to look. The Coords may be off by
5-10 feet, but that shouldn't matter.

Cache is in a safe, well-lit area (day and night), accessible from the
alley, and you will be out of sight of anybody (except for maybe the cache
owner) while doing business at the cache.

Despite these hints, the likelihood of finding the cache without solving the
puzzle is still next to nil, so good luck!