There are a few go-to games for the Atari 800 that I play frequently. One of them is a cops and robbers game called Getaway! Without getting into too much detail around the game play, you play the robber who canvases the city looking for treasure to steal and unmarked white vans to hi-jack and loot. The cops are roaming the city, essentially randomly, until you perform a specific action or a game play event takes place. One such action is robbing the white van, and an event could be the game transitioning to dusk or night fall. Once that happens, the cops immediately seek you out and give chase. As your score gets larger, they also become more suspicious and start chasing you sooner.

I find that the game gets considerably more difficult around 7000 points and I have yet to break the 8000 point barrier as of this writing.

As you progress through the game, there are different treasures that appear, giving different point values when you collect them. I wanted to know how many treasures there were in the game and what happens as you get to higher scores. Also, I have often thought that the game would be fun for young ids, if the police did not act so aggressively. They would have a blast driving around and collecting the treasure. Note that the game isn’t fun for an adult when this change is made, but a four year old would probably love it. If you find the modified game entertaining, you may not want to post that in the comments.

The author of the game, Mark Reid, released the source code to the game in 2017 on Github. It is written in assembly language but some of the basics can be puzzled out if you are familiar with a few core instructions. Like many computers of the era, the system is driven by a 6502 processor. Unlike many systems, it is clocked at a higher frequency than many of its competitors, running at a blazing 1.79 MHz for NTSC systems.

At any rate, I wanted to modify the game so that the cops would always remain in their random, passive state. The code refers to this state as “dumb” and the opposite behaviour as “smart.” To change it, just modify this piece of code:

COP031 CPX #4         ;Van is dumb
       BCS DUMB
       LDA RANDOM     ;if SKILL>RANDOM
       CMP SKILL      ; COPs smart
       BCC SMART

To this:

COP031 CPX #4         ;Van is dumb
       BCS DUMB
       LDA RANDOM     ;if SKILL>RANDOM
       CMP SKILL      ; COPs dumb
       BCC DUMB

Assemble the code. I think I needed to fix a few issues first, such as disabling debug mode which is found at the top of the module. If you leave the debug mode set to ‘2’, it will produce a weird looking map by default.

;
; compilation flags
;
DEBUG = 0 ; nonzero includes debugging code & sets debug map

There may also have been a few include paths that needed to be changed as well. At any rate, once those changes are done the assembler will produce a “getaway.exe” file. It is not a Windows executable file so don’t try and run it; just rename it to “getaway.xex” since that seems to be the format. I copied the file to my Lotharek drive and played it on the Atari, you could also choose to fire it up in an emulator.

Categories: Atari 8-bit, Games, Programming
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