KIM-Venture is an adventure game based on Colossal Cave written for the KIM-1. The program and its documentation are Copyright © Robert Leedom and I make no claims to any of this material. I have gathered everything together here for posterity.
Included here are both paper tape and HEX format files. The HEX files can be used on a KIM-1 clone from Coresham Tech, especially if you have their SD card system.
Load the Venture-ZeroPage, Venture-Game, and Venture-Extra files in any order.
Start the game by going to address $0100 and pressing GO.
When you are finished, load Venture-Scoring and run from $0100 to see how you did.
Note that the scoring program overwrites some page zero locations. If you want to be able to go back to your game after seeing your score, then you will need to save page zero first, then run the scoring program, then load your saved file and also Venture-Game again and restart at $0100.
The original tape IDs of these files are:
| ID | File |
|---|---|
| A1 | Venture-ZeroPage |
| A2 | Venture-Game |
| A3 | Venture-Extra |
| 06 | Venture-Scoring |
If you are using the KIM-1 clone, then you will not be able to load the Venture-Game or Venture-Scoring as HEX files from the SD card system completely because the extended monitor uses the stack. Load them from the paper tape files instead.
You can save the state of your game by saving a copy of zero page (from $00 to $EE) and making a note of the contents of location $03BD.
Return to the game by loading your saved file instead of the original zero page data when you load the program and setting the contents of $03BD to the value you noted.
For the full version mentioned below (in an expanded KIM-1), record and restore the contents of $04BD instead of $03BD.
Included here are:
- The Instructions for playing the game.
- The Game Manual containing information about how to load and run the game.
The source directory contains the original source code for the game with all original comments and formatting preserved. There is one change from the original, though. In Game.asm in the Main Move Loop, the original code used absolute addressing for the INC NMBUTS statement. My assembler uses zero page addressing when possible which would make this a 2-byte instruction instead of 3-byte, so I have added a NOP to preserve addresses in the output.
The following files contain the source code:
| File | Content |
|---|---|
| ZeroPage.asm | data to be loaded into zero page |
| Light.asm | The LIGHT subroutine which compiles into the start of zero page |
| Game.asm | The actual game which loads into pages 1, 2, and 3 |
| Extra.asm | Some support subroutines which load into the 6530 RAM |
| Scoring.asm | The scoring program |
These source files (except ZeroPage.asm) are location agnostic. This allows them to be recompiled into alternate addresses.
The above code can be compiled using the following files:
| File | Content |
|---|---|
| Venture-ZeroPage.asm | Combines LIGHT with the zero page data |
| Venture-Game.asm | Creates the actual game |
| Venture-Extra.asm | Creates the file loaded into 6530 RAM |
| Venture-Scoring.asm | Creates the scoring program |
| Venture-Full.asm | Creates a combimed program for a KIM with extended memory (or the KIM-1 clone) |
These files are necessary as the individual source files refer to locations and subroutines located in the other parts. They can only be assembled together. Each of the above files contains a directive causing only the relavent part to be output, enabling the separate program files to be created.
For the Venture-Full version, the game starts at $0200 instead of $0100 and avoids using any locations in page 1 (the 6502 stack). You can stop the program to view your score at any time. Press ST to stop the program and change to address $0600 and GO. Press ST again and rejoin the game from $0200.
The Venture-Full file does not include the zero page data so that must be loaded separately and will update the location of the message table in POINTR when run. This is partly to avoid trying to load data through stack locations (which could mess up the loading process) and also to make it easier to keep copies of the zero page data in order to save the state of a game.
Saved copies of zero page from the original multi-part program can correctly be used by this full version (because it updates the location of the messages), but if you wish to use a copy of zero page from the full program with the original, then you will need to change the contents of location $4B to be $03 after loading.
NOTE: The Venture-Full version is a work in progress - try it at your own risk!!