My first program - "Hello World!" for Atari 2600 Posted by rvertulo on August 26 2024 14:45:55Finally, I have started my studies on creating games for the Atari 2600 platform, and I must admit it's been a whole new world for me. Despite my decades of experience in software and game development for computers in general, the Atari 2600 architecture has proven to be quite challenging. I could have started with Batari Basic to make things easier, but I decided to venture into the world of Assembly for the 6507 microprocessor to make things more interesting and to improve my skills in this language, which I consider to be one of the few that still instills a bit of "fear" in me.
In these articles I'm writing, I don't intend to create a course or tutorial on Atari 2600 development. Instead, I aim to simply record my main impressions during my learning process.
I am following the magnificent book by Oscar Toledo G. called "Programming Games for Atari 2600," and right at the beginning, he shows how to color the screen's background with a solid color—in my case, I used red. Initially, I just copied the code from the book to get familiar with the Assembly programming style. Once the code was ready, I spent some time contemplating it and reflecting on what I had just done. The next day, I decided to try to recreate the code, but this time without following the book, attempting to rationalize what I had done the previous day. It worked!
After a few minutes of recreating the program, I achieved the expected result and managed to paint the screen background red without needing to "copy" from the book. Something that can be done with half a dozen lines in a high-level programming language required 57 lines in Assembly for the Atari 2600. This is because it's entirely up to the programmer to specify exactly how the hardware should be "configured" to achieve the desired result. While in higher-level languages, the main concern is the logic of what we are developing, with Assembly, we must also worry about dealing with the platform's hardware.
In this first lesson, the main thing I learned was to understand the structure of Assembly code for the Atari 2600 and that it is necessary to wait for the tracing of some lines on the monitor screen before and after the part that will actually be responsible for drawing visible elements. Specifically, it is necessary to wait for three traces for VSYNC, thirty-seven for VBLANK, and at the end, another thirty traces for OVERSCAN.
That's all for this first article. See you soon!
Result for the first program using Assembly Language for Atari 2600.
