This repository contains a collection of C64 assembly programettes / snippets that demonstrate different behaviors in the C64 architecture. This repository can be a useful resource for learning C64 programming (through Kick Assembler).
IMPORTANT: this project is for educational purposes. You can compile and run,
modify and do whatever you like with the example code.
The code can be assembled with Kick Assembler https://theweb.dk/KickAssembler but if you only want to test,
I included the .prg executable files that you can insert into an emulator or write to cassettes,
floppies or whatever that makes you happy :)
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💡 1_border_color - setting the border color is very easy and equally rewarding. You can do something flashy, with a short bit of code to modify the outlook of your target machine. You can start to understand the process from here. You can check out the
/all_colorsdirectory below to learn more. -
💡 2_constants_and_variables one of the most important parts of any programming language. Simple and easy concept to grasp, and important to master.
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💡 3_basic_arithmetic_registers there are 3 registers (there are two + 1 more later) in the MOS 6502 / 6510 CPU 'A' and two index registers 'X' and 'Y' here we learn about them.
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💡 4_tables we already checked out variables so talbes are pretty simple to get some grasp on. They can work similarly to arrays in modern programming.
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💡 5_hello_world the first complex program we write in this tutorial package. This is complex, so don't get discouraged if it is hard at first then it will be very satisfying when you understand how it works. Here, I've explained every step in comments, so hopefully you will get the hang of it with a little bit of playing around. I encourage trial and error ways of learning.
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🏁 FIRST_CHALLENGE we have learned enough, that you can start writing your own simple programs. I encourage that you write as many as you can, so you discover all the pitfalls and best practices of the concepts we have learned.
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💡 7_basic_math_with_c64 we have learned about the 'A' register and hint about it's math capabilities so let's check out how it works. In this example we learn simple 8 bit addition and subtraction. Division and multiplication is not built in to the CPU - so if you need something like that, you have to program it yourself. That's a great excersize after this chapter (maybe a little bit too advanced, but if you feel adventureous you can try a simple multiplier).
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💡 8_if_else_branching One of the most important aspect of every programming language is to be able to build a control flow in this chapter we'll learn about the BEQ, BCC, BCS mnemonics (bsc opcodes) to be able to create branches on previous comparisons (CPX, CPY)
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💡 9_screen_memory We will see in this chapter (or example) that we can address every single cell (8px x 8px area) of the screen from the address
$0400we can start addressing each cell one by one, storing a screen code - which represents a symbol (letter, number or some special character) - and from the memory$d800we can use our favourite 16 colors in quite the fun configurations, so we will be able to generate something like this, with only just a few lines of assembly code.
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💡 10_keyboard_detection detecting keyboard strokes is a pretty important feature for any computer program - especially for a commodore 64 program. When we try to control our player in games, or select options in a program, we rely on the computer being able to capture our keyboard strokes runtime and use it to compute some outcome (move a sprite on x or y axis or dispatch some event, or calculate with the keycode of the triggered key)
Here I list some sources you can use for learning
A useful resource from a very nice and smart guy on youtube who explains the concepts in details. This example list is somewhat following his tutorials. I highly suggest his tutorials on the topic:
And also you can check out his channel Commodore Tutorials