X16 Assembly Tutorial

SlithyMatt · Post by **SlithyMatt** » Mon May 03, 2021 4:24 pm

Lesson 17: FM Synthesis

wahsp · Post by **wahsp** » Mon May 03, 2021 7:05 pm

Wow! I didn't know the Commander X16 is capable of FM. I played around a lot with software synths over the years. FM is definitely one of the more interesting approaches to synthesis, if you ask me. There are so many directions you can take it in.

SlithyMatt · Post by **SlithyMatt** » Mon May 17, 2021 3:05 pm

Episode 18: Sprites

Nadia · Post by **Nadia** » Sat May 22, 2021 5:24 pm

@SlithyMatt Hi I am a new programmer who is having a lot of difficultly understanding the assembly tutorials. I did some basic tutorials for the x16 but the program I want to write would be very difficult to write in basic, which I why I decided that assembly may be my best option. Do you have any advice for figuring out assembly for a beginner. I understand that I am calling things and preforming operations at certain hexadecimal addresses but when things like stack pointers are brought up it becomes very confusing and I have trouble understanding what is going on when I call these hexadecimal addresses. I understand that this is supposed to be more advanced because I am writing machine code, so I am not faulting your tutorials... just wondering if you have any advice to make it easier to understand.

borgar · Post by **borgar** » Sat May 22, 2021 7:00 pm

There are plenty of tutorials for 6502 assembly out there (here is one that starts gently https://codeburst.io/an-introduction-to-6502-assembly-and-low-level-programming-7c11fa6b9cb9). It might not be a bad idea to do read a few such documents before jumping into videos.

I think you probably should not start out with something too ambitious for your first attempts. You probably can a lot of smaller programs without having to deal directly with the stack pointer. You can start by transferring parameters in the registers (A, X and Y) and/or direct memory addresses (Zero Page or not) and limit your self to implicit stack use with JSR/RTS.

I'd also recommend taking looking at Prog8 (https://prog8.readthedocs.io/en/latest/#). This gives you something a lot faster than Basic while not being as completely low level as assembly. Prog8 allow inclusion of assembly into the program fairly gracefully when you need "full speed" and if you just need a few really fast (non-recursive) functions you don't not need to learn to use the program stack. And since Prog8 produces assembly output (before producing the binary with 64tass) it will also allow you to learn a lot from looking at the produced output when you are interested.

BTW, back in the day (80's) when I did some limited machine code programming I basically had no understanding of the stack and the only stack related commands I used was just JSR and RTS. But what I wrote then was basically stuff gleaned from some assembly examples in various C64 magazines and I probably only understood about half the 6502 instruction set.

Nadia · Post by **Nadia** » Sat May 22, 2021 7:13 pm

4 minutes ago, borgar said:

There are plenty of tutorials for 6502 assembly out there (here is one that starts gently https://codeburst.io/an-introduction-to-6502-assembly-and-low-level-programming-7c11fa6b9cb9). It might not be a bad idea to do read a few such documents before jumping into videos.

I think you probably should not start out with something too ambitious for your first attempts. You probably can a lot of smaller programs without having to deal directly with the stack pointer. You can start by transferring parameters in the registers (A, X and Y) and/or direct memory addresses (Zero Page or not) and limit your self to implicit stack use with JSR/RTS.

I'd also recommend taking looking at Prog8 (https://prog8.readthedocs.io/en/latest/#). This gives you something a lot faster than Basic while not being as completely low level as assembly. Prog8 allow inclusion of assembly into the program fairly gracefully when you need "full speed" and if you just need a few really fast (non-recursive) functions you don't not need to learn to use the program stack. And since Prog8 produces assembly output (before producing the binary with 64tass) it will also allow you to learn a lot from looking at the produced output when you are interested.

BTW, back in the day (80's) when I did some limited machine code programming I basically had no understanding of the stack and the only stack related commands I used was just JSR and RTS. But what I wrote then was basically stuff gleaned from some assembly examples in various C64 magazines and I probably only understood about half the 6502 instruction set.

Thanks for the links. My first program I want to write would be an appointment Calendar for the x16 with some nice graphics for the day. Once program loads you type in the month that you want to add data to. then once on that screen you type in the day number which would open an editor to add times of reminders and description for that day. Once you are done writing all the appointments you have for that month you can save the updated calendar file either to the hard disc or to a floppy for load up later. I figured this maybe too hard to write in

basic so I thought maybe handling more variables would be more suited for assembly. Again thanks for the links, I will continue to follow the series on YT while also reading this more basic documentation and hopefully eventually everything will start clicking in my head.

x16tial · Post by **x16tial** » Sun May 23, 2021 2:58 am

This is a great 6502 tutorial: https://skilldrick.github.io/easy6502/

And pretty much all of what you learn there can be applied to the 65C02. I basically started with that tutorial, and then did a bunch of stuff in the VICE C64 emulator. At first I was using a Fast Load cartridge image and its built in monitor to do simple Assembly programs. Then graduated to the Super Snapshot and its built in monitor, but also Turbo Macro Pro (this is all still on the C64). @Robin Harbron in his 8-bit Show And Tell channel on YouTube turned me on to Super Snapshot and Turbo Macro Pro. Here is his Assembly Language playlist:

I'd recommend cutting your Assembly Language teeth on the C64 (the 6510 is a 6502 with just a few changes). As the C64 is a fixed and known platform with 35+ years of information that can be easily found on the web. Then once you're more comfortable with 6502 Assembly, start learning the in's and out's of the X16 and VERA, which should be relatively quick and easy at that point.

johnzo · Post by **johnzo** » Thu Jul 29, 2021 5:47 am

just wanted to pop in and say thanks to Matt for these outstanding tutorials! Looking at the slides, the scripts, and especially the nice clean per-topic demos, seems like there must be hours of work in each hour of video.

voltage · Post by **voltage** » Tue Aug 17, 2021 1:47 am

I also want to give @SlithyMatt a huge shout out!

Thanks for the amazing tutorials, very high production value and well thought out and explained info.

I procrastinated the whole day away absorbing these vids, very much appreciated.

rje · Post by **rje** » Thu Aug 19, 2021 3:23 pm

Matt, this is an absolutely GIGANTIC and USEFUL resource pile you've created. I'm going to have to find time to watch them all.

Thank you!