LADDER


The classic CP/M game Ladder reverse engineered in Turbo Pascal.

Original GitHub repository: https://github.com/mecparts/Ladder

Additional information and compiled version by Anna Christina Naß
acn@acn.wtf

I've added a compiled LADDER.COM file for just playing the game (on a
VT100 terminal at about 8 MHz, eg. a RC2014), and added more information
on compiling the game.


Keys

The file LADDER.DAT is the configuration file that holds the key
definitions. These can be changed by using LADCONF.COM (the terminal
definition in LADCONF is not used! This LADDER uses the Turbo Pascal
terminal definitions).

The default keys in this LADDER.DAT are:

    Up = 8  Down = 2  Left = 4  Right = 6
    Jump = Space   Stop = Other

(Jump and Stop are not configurable)

Also, "bell" sound is enabled and "wise crack marks" are disabled.


Compiling notes from Anna:

To compile LADDER, just use Turbo Pascal from the TP/ directory. It's TP
3.0A for CP/M-80, only without the demo source code.

-   Copy the TP files together with the LADDER files to one disk
-   The terminal definition is already set to ANSI and the speed is set
    to 8 MHz (for a standard RC2014), so running TINST is not needed
-   Run Turbo Pascal using TURBO
-   Set the compiler options to "compile -> Com-file" (press O, C, Q)
-   Compile LADDER.PAS: press C (Compile), then enter ladder as Work
    file name.

This should result in a LADDER.COM file.

The rest of this file is mostly the README from the original repository.



ORIGINAL README CONTENT:


About

This is a rewrite in Turbo Pascal of the classic CP/M game "Ladder",
originally written by Yahoo Software (not Yahoo!).

Ladder is an ASCII character based platform arcade game similar to
Donkey Kong. You travel through levels with platforms and ladders where
rocks fall down from the top while you collect statues before reaching
the exit.

Back in 1999 Stephen Ostermiller made a version of Ladder in Java.
Later, Mats Engstrom of SmallRoomLabs started another version in of
Ladder in golang. Between my own memories of playing the original game
on a Kaypro, and Stephen Ostermiller's and Mats Engstrom's code, I was
able to come up with this version.

This version will use the original LADCONF.COM configuration program and
LADDER.DAT configuration file. Since this version is a Turbo Pascal
program, the terminal configuration portion of LADCONF isn't used,
though it still does set up the movement keys, sound and back chatter
options.


Compiling the game

You'd need Turbo Pascal, of course. You'll also need to edit
LADCONST.PAS to set the cursor on and off sequences for your terminal.
LADDER.PAS is the main part of the program. I've successfully compiled
this on a 58K CP/M system, so available RAM isn't a particularly
critical limitation.

Once you've compiled LADDER.COM, copy LADCONF.COM to the same user area.
If you don't have a LADDER.DAT file, when you run LADDER the first time
it'll automatically load LADCONF to set up the movement keys and
options, then transfer you back to LADDER.


Limitations

At the moment, once you've successfully completed the 7th distinct level
(Gang Land), the program just cycles through all 7 seven levels over and
over again until the bonus time becomes too short to actually finish a
level. If anyone knows what the original program actually did (I never
managed to get anywhere near to completing the original game), let me
know and I'll see what I can do.

The Delay(ms) call in Turbo Pascal only works for a Z80 running at up to
32MHz (and TINST will only allow you to specify a value of up to 20MHZ
if I recall correctly). So if you're trying to run this on a system with
an effective clock speed of greater than 32MHz, you're going to have to
come up with another mechanism. That's not an insurmountable roadblock
though; on my 144MHz-Z80-equivalent RunCPM box running on a Teensy 4.0,
I patched the Turbo Pascal runtime to make a call to a BDOS extension I
created to call the Arduino's delay() function. Works like a charm. If
your system includes any kind of millisecond counter you can read,
that's a good spot to start looking.


References

Original Ladder game Ladder in Java Ladder in golang