My running joke after showing off some amazing LLM-driven work is...
if you think this is impressive, I once opened a modal dialog on an Apple IIGS in 65C816 assembly
I don't think you need to learn BASIC, if you know concepts like conditionals and looping and indexing. It is interesting to compare the higher-level language of the time with its companion assembly. And you might find yourself writing BASIC programs to complement your assembly, if you stick to that platform.
<lore>
A friend dropped me a BASIC program that ran and wrote text to the Apple IIGS border. He asked me to figure it out, because it wasn't obvious what was going on. OG hacker puzzle... it was a BASIC program that jumped to hidden assembly after the apparent end of the text file (hidden chars maybe, I forget) and the assembly was changing the border at appropriate rate to "draw" on it. Those were the days... trying to find some reference to this and am failing.
</lore>
I certainly credit my stack-frame debugging capability to dealing with that stuff so long ago. Oddly enough, I didn't really find it helpful for computer architecture class. Just because you know registers exists and how to manipulate them, doesn't exactly map architecting modern hardware system. But being fluent in logic operations and bit-twiddling and indexing does help a lot.
Check the books section and find something that compels you.
Also, don't forget the HUGE number of resources for 6502 assembly programming that are available in the https://archive.org/ magazine and book sections:
Its not absolutely necessary to learn BASIC before Assembly, but it will definitely help you understand the resources of the machine better if you can debug BASIC ROM code. My personal 6502 platform of choice, the Oric-1/Atmos machines, has a pretty great ROM disassembly available, from which a lot of great knowledge can be obtained - but it does of course first require an undersanding of BASIC.
In case you're curious, the Oric-1 ROM Disassembly:
Nothing wrong with internet searches (though I find Google is most useful for results from Google sites).
But HN is full of 6502 enthusiasts, so I approve of tapping their collective wisdom to discover personal favorites and recommendations.
Unlike modern computers, 8-bit systems were expected to be programmed by their owners! As a result there are many books from the 8-bit, pre-internet era explaining exactly how to do so, and many of those books are conveniently available on the modern internet (perhaps via a google or other search, or on archive.org, etc.) Many systems also came with user instruction manuals explaining how to program them.
Note how it explains everything from scratch, including how to hook the Apple II up to a TV, how to use the keyboard, and how to start up BASIC.
BASIC was designed as a simple but effective programming language that could be learned by computing novices (first year college students) in an afternoon. Here is the original Dartmouth BASIC manual (23 pages long!) from 1964:
I don't think online tutorials are a good ressources to learn programming. We just have to look at what juniors can do nowadays (they can't even write a simple program, and I'm from that generation). That's why I asked for books.
You don't have any programming experience, and yet hold strong opinions on good resources to learn programming? There's some wonderful book recommendations in this thread, but I wouldn't underestimate how much great long-form content and tutorials there are on the Web these days (vs just learning by copying snippets off StackExchange)
Definitely develop some capabilities to accomplish an elementary satisfying project in BASIC.
It's the language that was designed for you to learn about programming and a computer language at the same time.
Whether or not you actually "master" the language or just barely learn a few commands, before using a few commands to make a simple finished program. One approach would surely be a lot faster than the other ;)
After that then decide how much you learned about programming itself from the little project, then you can see how far that BASIC alone may be able to advance your programming abilities even after you may be very familiar with the language in detail, or not.
In that '80's generation of home computers with a 6502, most had built-in BASIC so a common progression for so many was to learn BASIC at the same time as learn programming, since nobody had ever had home computers before. This could be just fine for business applications. Assembly is not nearly as easy as BASIC to learn, but in some sense programming is programming.
Then for gaming BASIC was not nearly as fast as assembly but often BASIC performed just fine anyway for developing the logical game flow and making it a "fun" game at its core to begin with. The problem with BASIC was all the other little details like video, I/O, UI, HID, were all so dramatically slower because each BASIC command needed to be interpreted before it could be run on the hardware and that took a little extra time in between each command but it really added up when you have challenging hardware interfaces and not simply fundamental game logic (many times game logic can be so simple that it's never slow in any language).
For a plain BASIC game that is "complete" but is supposed to have quick action and low latency, the next step in the learning curve would then be to find out which part of the BASIC code is the main resource bottleneck when it comes to processing time, then replace that one function with an equivalent written in assembly. It was accepted that it was a lot more work then to introduce assembly to make the game do the same thing it was before, only quicker.
It may not be very clear looking back, but there were a number of good reference books and instructional approaches and so much of it was intertwined with "learn BASIC + programming at the same time" followed by "useful assembly language techniques" to speed up your programs.
As crowds moved along these lines together to a degree as they emerged, it might help to look at publication dates for the books of the time, and use what's found in the earlier texts to help you with later concepts.
This book specifically targets beginners that are new to 6502 assembly. The examples cover all of the 1980s-era computers including the Apple II. It's free on archive.org and the introductory chapters are worth reading.
I believe one of the "standard works" to learn 6502 back in the day was Programming the 6502 by Rodnay Zaks. It's out of print, but it was printed in a lot of copies so you should be able to find one second-hand.
I'm seconding the recommendation to look at Rodnay Zack's books. For example, I really enjoyed Advanced 6502 Programming. It's a project-based tutorial for a custom 6502 machine. The design and schematics are in the book.
WRT advanced 6502 programming texts, allow me plug my (free) book "EOR #$FF: 6502 Ponderables and Befuddlements". It's 64 assembly snippets to ponder, with explanations for each in the 2nd-half of the book: https://archive.org/details/eor6502
Seconded. I bought the first edition of "Programming the 6502" way back in the neolithic, and I enjoyed it greatly. I even read parts of it again now and then these days too, just because I like it.
I used to write assembly on, at first, the AIM-65, and later the Apple II.
Is Programming the 6502 enough to learn Assembly on the Apple II ? But it doesn't explain the memory and screen management, right ? So how can we learn that ?
Someone can correct me if I'm wrong, but I believe the screen memory of the Commodore machines (ViC-20, Commodore 64) were the most straight-forward. As opposed to the more janky Apple II memory map.
You could do a lot worse than picking up a new Commodore 64 Ultimate [1]. They're a more or less faithful remake of the Commodore 64 but have an HDMI port, SD card instead of disk drive, etc. You could learn BASIC, should be able move to assembly as well—a quick search pulled up a YouTube course on 6502 assembly for the Commodore [2].
(I realize I am not contributing "books"—but others have done well in this regard. I did want to share what I think is a pragmatic way to learn 6502.)
Is the Apple II Reference Manual good for that ? Or anything specific to the Apple II, like "What's Where in the Apple" or "Understanding the Apple II" ?
> And is it absolutely necessary to learn BASIC before Assembly
If you don't have experience programming, learning BASIC before Assembly will be super helpful before you learn 6502.
If you only have experience programming in modern languages (Javascript, etc.), learning the Applesoft BASIC will also be super helpful before you learn 6502, as you'll learn how to get by without ...
A) the following language conveniences:
- function names (it's all line numbers),
- variables with more than 2 letters,
and
B) the following modern concepts:
- function calls (no stack other than for GOSUB, use subroutines with dedicated variables for passing parameters instead),
- scoped variables (everything is global),
- dynamic allocation (you have to DIM arrays with the max size upfront),
- anything object-like like structs or classes (hack it with multi-dimensional arrays)
- other fancy stuff like callbacks, promises, hashtables and any other data structure beyond arrays.
and that will nicely prepare you for 6502 assembly (or any kind of assembly really). The advantage in 6502 assembly is you can implement most of B) yourself if you do need it.
There are a few distinct things here. Learning 6502 assembly is straightforward, and you'd be better learning about simple (not modern) assembly languages at a high level--opcodes, registers, noop, branch, jump, compare, accumulators, program counters, and clock cycles. From there, start writing 6502 in an emulator and seeing what happens. That's where you're going to learn, and the feedback will be a lot faster. Programming for an Apple II will be more about learning how to interact with devices through memory.
This is how I learned. This book is great. I have the worn paper copy sitting 6 feet behind me as I type this. It's worth getting a paper copy if that is still possible.
Looks like a nice book, and it appears that he wrote books on other microprocessors (8080/8085, 8086, Z-80, Z8000, 6800, 6809, 68000... even SPARC apparently) as well. I'd like to find a full version of the 68000 book, which archive.org only seems to offer a preview of.
The Apple II Reference Manual includes assembly listings (with full comments!) for the Monitor ROM and Autostart ROM, the mini-assembler, floating point routines, and a very nice 16-bit "pseudo machine interpreter" called SWEET 16. Most of which was written by Steve Wozniak. Learned a lot from this book back in the day.
Here's a link from archive.org. It's not the best scan, but you can easily find other copies.
If you're feeling adventurous, you can find assembly listings for the AppleSoft BASIC language (though maybe only from third parties). It's pretty huge.
and it includes a link to the documented source code for Akalabeth (also known as Ultima 0)
Somewhere, there's an article discussing the assembly-language like bit-blitting used to draw the high-res graphics in a timely fashion and the variable/memory management techniques needed to drive that which I'm sure a bit of searching will turn up (or one can derive it from the source).
They screen memory layout on the Apple II was a clever hardware hack but makes programming the machine more difficult. I think you'd be better off using a "trainer", like a KIM-1 simulator [0] to get your feet wet. (The KIM-1 was made by MOS Technologies, manufacturers of the 6502, as a demonstration and prototyping platform for the CPU.)
If you can do simple exercises on a machine like that and get comfortable with simple operations (loops, memory addressing modes) I think you'd have a better time grokking something more feature-filled.
If you aren't doing hires graphics, you don't have to mess with the screen memory directly. You can just call the ROM routines which has the nice side effect of working with 40- or 80-columns automatically. If you are doing hires graphics you are going to use a lookup table regardless as doing the multiplication to get the base address of a particular scanline is far too slow. You can, one time, either make a table manually, which you can use forever, or you can write a short routine that counts from 0 to 191, stick 0 in X and the scanline number in A and JSR $F411. It'll leave the base address of the scanline in $36 and $37. Which you can stick in your table.
As in other comments, if you are specifically interested in the Apple II line, the Assembly Lines books by Roger Wagner is fantastic.
Also, if you can find it Sandy Mossberg's Disassembly Lines articles in Nibble magazine were great too. Start with Assembly Lines, then read the Disassembly Lines and you'll be quite expert.
These two books will give you a good understanding of 6502 assembler - it is general but gives a good background and has a nice assembler with a full walk through of the code. I used these two books to learn 6502 on my Commodore 64 and they are highly recommended.
These are great books. I had them in paper, and they were great for understanding both how the 6502 worked, and metaphors for managing higher level constructs in ML.
Don't overlook (if you can find them) books made for Commodore-64 assembly coders. (Same CPU.) While they won't contain II specifics, there were several that were very helpful with 6502 tricks.
[Off TOpic somewhat] This post made me immediately recall, the hours I spent playing
Apple Invaders, 1979
Pinball Construction Set, by Bill Bludge
Chop Lifter, modeled on 1979–1981 Iran Hostage Crisis, Dan Gorlin, Brøderbund 1982
Castle Wolfenstein (1981) (Muse) by Silas Warner
Red Alert (1981) Olaf Lubeck, Broderbund
I still have some of these original games and the artwork in the shed.....
All classic Apple games of very early 80s
At the time, the programming was recognized as amazing, the sound and graphics.
It was a marvel that it was achieved on such a low resource machine ....
Original Apple II manuals written by Chris Espinosa and Jef Raskin are a treat to read. Would highly recommend, just to get a sense of what it was like to get onboarded on Apple II back in the day.
And then obviously Programming the 6502 by Rodnay Zaks.
You don't need to learn BASIC first but it might be helpful for bootstrapping at the beginning. Since it's included in the computer you can PEEK and POKE memory locations from BASIC and get a feel for how memory and machine code works without needing to understand the whole entire hardware, bootloading process, etc. first.
In my opinion BASIC, with its line numbers and GOTO / GOSUB feels assembly-ish anyway - you'll be doing a lot of JMP / JSR to control program flow which is different to how modern high levels are normally written.
Learning BASIC isn't essential, but the thing is, you might as well just do it. It's not complicated, and you're not under any obligation to develop a big piece of software with it. Have fun!
RE "....Books to learn 6502 ASM and the Apple II...."
Suggest to look at some of the archives of old Apple Magazines from around the Apple I era , cira late 70s and early 80s.
Some of them would have had assembly language programming columns.
I recall one Named Softtalk , but there where many.
There are other Sites than Archive.org. Some archive sites solely devoted to early apple computers like Apple 2
I strongly recommend "What's Where in the Apple": https://archive.org/details/whatswhereinappl0000lueb
I loved that book back in the day. Specific, directly addressable memory locations are mapped to system devices in a way that is quite foreign and Wild West when compared to modern computer architectures.
I have fond memories from the late 1980s of trying to get the assembler contained within this book working, typing line after line of the MLX listing in. Unfortunately I never did finish it back then.
A week or so ago I got the urge to complete this project and I literally just finished getting the source in it to a point where it can be compiled online and then within an emulator: https://github.com/jlmcgraw/LADS_DOS33
Lance Leventhal's CPU books are pretty comprehensive and make it easy to switch from one architecture to another. Learning BASIC is definitely not a requirement.
Honestly if you want to learn retro stuff for retro reasons... maybe consider using the retro materials? Here's the MOS programming manual for the original parts, it's what Woz would have used when hand-assembling Integer BASIC:
And it's really not so complicated! The chip is simple, so the docs are simple. There's more to read about the history to come later, but there's also something to be said for understanding it in the context its designers presented it.
The answer would depend on what programming experience you have?
Do you have any assembly language experience ? with other targets?
ie have you used an assembler ( and maybe linker ) before.
Are you familiar with hex? bytes, bits etc , You will learn this and much more ...
Id look for a book that targets Assembly programming on a Apple 2, ie not a book on general 6502 programming.
Such a book Id expect to discuss things like Apple 2 memory map , Apple 2 hardware and how they are used in assembler language.
Hopefully the book would also provide guidance using a particular assembler ( hopefully still available)
I googled phrase
Apple 2 assembly language programming for beginners?
and lots of very good looking links popped up.
You aim is a challenging task. Much to learn. Good luck. However entirely do able these days.
My background is electronics engineer, embedded programing on in assembler (some Motorola processors and others) and C for a few years before moving on to other things ....
Assembly is a type of programming that is unlike most programming languages, and as such, would be a really tough introduction to the field.
Can you explain a bit more about how you became interested in assembly and programming the Apple II? And specifically, why you want to start the journey towards programming there?
I respectfully disagree, BASIC/Java/Arduino hides too much about how the CPU works from users.
Getting a 6502 kit from Ben Eater, and walking though how the CPU works will implicitly show how languages abstracted away whats actually happening. And more importantly, the skills necessary to understand how to write efficient programs.
I second this -- I just found the Ben Eater series a month or so ago and put together his computer clock over the holidays. It really helps you understand clock cycles, logic chips, etc, and is a good foundation for the 6502 kit you build later in the course. And learning Assembly before BASIC is the right learning path IMO, if only to understand how CPU registers work at the electron level.
If one is interested in how internal PC registers work, than these build series do the classic eeprom microcode based CPU builds. Fabian's series is highly accessible, and builds a python based assembler from scratch. James series ends with a simple game design.
Starting with Assembly is simply a bad idea because the tooling is terrible, and the learning curve of the tooling is steep. Filled with arcane codes and abbreviations and workflow right out the gate.
Programming concepts are pretty much universal. Being distanced from computer architecture is not a limitation for novice programmers, Python et al succeeds for a reason.
If you're determined to start with assembly, then I hope you can find someone to help you get started with all the machinations necessary to get from LDA #0 to A9 00 with as little drama as possible. Someone to show you how to use the assembler, what the directives mean, the linker, a symbolic debugger (if you're lucky). Someone to provide you with a .DUMPREG "START OF SORT" and .DUMPMEM BUFF $80 "AFTER INPUT" macros that you can liberally scatter throughout your code so you actually progress and get some insight into what the heck you code is doing. Perhaps some way to stop your programs that doesn't include hitting the reset button on the machine.
I mention that because, again, the tooling is terrible. All of the is easier said than done. None of the assembly books address this, none of the assembly program reference guides do either. Assembly is VERY black box. It's a large step up to even get started.
It's much easier to "learn programming" first at a higher level, where you can quickly progress and succeed, before turning into the dark hole that is assembly, particularly on older machines.
At least on a KIM-1 you can hit the STOP button and cursor through memory (being conscious that the memory architecture of the KIM is quite funky), something that simple is quite difficult on an Apple ][.
In general, Assembly for a simple well documented CPU is fairly close to most familiar calculator operations, and is demonstrated as a 1 to 1 relationship in the binary firmware. If folks drop on abstractions like Scratch/Basic/Python/Java the students will develop a random notion of what Register/Stack/Heap even means.
I would recommend looking at a few random samples of Ben's build series, as he covers most first year subjects in subtle efficient ways.
Soldering kit PCB or Emulators are insufficient to demonstrate a physical bus wire harness, clock timing, and memory layout. Best of luck =3
Starting with the 6502 is going to bring you up hard against its addressing modes. Better IMHO to learn about memory and how to access it using arrays in BASIC first.
My opinion differs - learning how memory is accessed via assembly language will make it super easy to understand e.g. how C pointers actually work, something which can be surprisingly difficult for those who go directly to a high level (compared to assembly) language, but very easy if you come from machine code/assembly.
My running joke after showing off some amazing LLM-driven work is...
if you think this is impressive, I once opened a modal dialog on an Apple IIGS in 65C816 assembly
I don't think you need to learn BASIC, if you know concepts like conditionals and looping and indexing. It is interesting to compare the higher-level language of the time with its companion assembly. And you might find yourself writing BASIC programs to complement your assembly, if you stick to that platform.
<lore> A friend dropped me a BASIC program that ran and wrote text to the Apple IIGS border. He asked me to figure it out, because it wasn't obvious what was going on. OG hacker puzzle... it was a BASIC program that jumped to hidden assembly after the apparent end of the text file (hidden chars maybe, I forget) and the assembly was changing the border at appropriate rate to "draw" on it. Those were the days... trying to find some reference to this and am failing. </lore>
I certainly credit my stack-frame debugging capability to dealing with that stuff so long ago. Oddly enough, I didn't really find it helpful for computer architecture class. Just because you know registers exists and how to manipulate them, doesn't exactly map architecting modern hardware system. But being fluent in logic operations and bit-twiddling and indexing does help a lot.
Pretty much the best resource available:
https://6502.org/
Check the books section and find something that compels you.
Also, don't forget the HUGE number of resources for 6502 assembly programming that are available in the https://archive.org/ magazine and book sections:
https://archive.org/search?query=6502
Rodney Zaks' books are great - I like especially "6502 Games", which taught me a lot back in the day:
https://archive.org/download/6502g/6502Games.pdf
I'm also especially fond of the easy6502 emulator - its a very handy tool to have while studying 6502 techniques:
https://skilldrick.github.io/easy6502/
Its not absolutely necessary to learn BASIC before Assembly, but it will definitely help you understand the resources of the machine better if you can debug BASIC ROM code. My personal 6502 platform of choice, the Oric-1/Atmos machines, has a pretty great ROM disassembly available, from which a lot of great knowledge can be obtained - but it does of course first require an undersanding of BASIC.
In case you're curious, the Oric-1 ROM Disassembly:
https://library.defence-force.org/books/content/oric_advance...
(You can get an Oric emulator named Oricutron, or you can access a virtual Oric here: https://oric.games/ ..)
Good luck!
This is the book I used when I was writing serial drivers for Apple II ProDOS: https://archive.org/details/6502_Assembly_Language_Programmi...
And I have a vague memory of this book: https://archive.org/details/aiimp/mode/2up
Not sure what level you're at, but I can't remember if this is the text Jef Raskin wrote, but it's a decent backgrounder: https://archive.org/details/aiirm/mode/2up
I don't have any programming experience.
Google can be very helpful for these types of queries:
https://www.google.com/search?q=apple+2+game+programming+tut...
Formulating questions is a valuable skill as is finding existing resources.
As some one from that era, it is truly amazing how much information there is online about all aspects of 8 bit computers
Nothing wrong with internet searches (though I find Google is most useful for results from Google sites).
But HN is full of 6502 enthusiasts, so I approve of tapping their collective wisdom to discover personal favorites and recommendations.
Unlike modern computers, 8-bit systems were expected to be programmed by their owners! As a result there are many books from the 8-bit, pre-internet era explaining exactly how to do so, and many of those books are conveniently available on the modern internet (perhaps via a google or other search, or on archive.org, etc.) Many systems also came with user instruction manuals explaining how to program them.
Here is the Apple II BASIC manual from 1978:
https://archive.org/details/Apple_II_Basic_Programming_Manua...
Note how it explains everything from scratch, including how to hook the Apple II up to a TV, how to use the keyboard, and how to start up BASIC.
BASIC was designed as a simple but effective programming language that could be learned by computing novices (first year college students) in an afternoon. Here is the original Dartmouth BASIC manual (23 pages long!) from 1964:
https://www.dartmouth.edu/basicfifty/basicmanual_1964.pdf
I don't think online tutorials are a good ressources to learn programming. We just have to look at what juniors can do nowadays (they can't even write a simple program, and I'm from that generation). That's why I asked for books.
You don't have any programming experience, and yet hold strong opinions on good resources to learn programming? There's some wonderful book recommendations in this thread, but I wouldn't underestimate how much great long-form content and tutorials there are on the Web these days (vs just learning by copying snippets off StackExchange)
Definitely develop some capabilities to accomplish an elementary satisfying project in BASIC.
It's the language that was designed for you to learn about programming and a computer language at the same time.
Whether or not you actually "master" the language or just barely learn a few commands, before using a few commands to make a simple finished program. One approach would surely be a lot faster than the other ;)
After that then decide how much you learned about programming itself from the little project, then you can see how far that BASIC alone may be able to advance your programming abilities even after you may be very familiar with the language in detail, or not.
In that '80's generation of home computers with a 6502, most had built-in BASIC so a common progression for so many was to learn BASIC at the same time as learn programming, since nobody had ever had home computers before. This could be just fine for business applications. Assembly is not nearly as easy as BASIC to learn, but in some sense programming is programming.
Then for gaming BASIC was not nearly as fast as assembly but often BASIC performed just fine anyway for developing the logical game flow and making it a "fun" game at its core to begin with. The problem with BASIC was all the other little details like video, I/O, UI, HID, were all so dramatically slower because each BASIC command needed to be interpreted before it could be run on the hardware and that took a little extra time in between each command but it really added up when you have challenging hardware interfaces and not simply fundamental game logic (many times game logic can be so simple that it's never slow in any language).
For a plain BASIC game that is "complete" but is supposed to have quick action and low latency, the next step in the learning curve would then be to find out which part of the BASIC code is the main resource bottleneck when it comes to processing time, then replace that one function with an equivalent written in assembly. It was accepted that it was a lot more work then to introduce assembly to make the game do the same thing it was before, only quicker.
It may not be very clear looking back, but there were a number of good reference books and instructional approaches and so much of it was intertwined with "learn BASIC + programming at the same time" followed by "useful assembly language techniques" to speed up your programs.
As crowds moved along these lines together to a degree as they emerged, it might help to look at publication dates for the books of the time, and use what's found in the earlier texts to help you with later concepts.
For Apple-II specific info, consider
The Assembly Lines book -- https://archive.org/details/AssemblyLinesCompleteWagner
Understanding the Apple IIe -- https://archive.org/details/understandingapp0000sath
Understanding the Apple II -- https://archive.org/details/understanding_the_apple_ii
As mentioned in the link above, Assembly Lines is still in print as a paper book (maybe it's print on demand, but it's a hardcover).
I just noticed that Understanding the Apple IIe also got a re-issue from Call-A.P.P.L.E. in 2024 (print edition from Lulu) - https://www.callapple.org/books-3/understanding-the-apple-ii... .
Sather's book is the most comprehensive I've ever read. He even discusses the split screen vblank trick.
Assembly Lines is the one I came to recommend. Great book to sit down with and work your way through.
Machine Language for Beginners, Charles Mansfield https://archive.org/details/ataribooks-machine-language-for-...
This book specifically targets beginners that are new to 6502 assembly. The examples cover all of the 1980s-era computers including the Apple II. It's free on archive.org and the introductory chapters are worth reading.
This is what I read as a middle schooler learning 6502 on a C64. Does a good covering the basics in a very conversational manner.
I believe one of the "standard works" to learn 6502 back in the day was Programming the 6502 by Rodnay Zaks. It's out of print, but it was printed in a lot of copies so you should be able to find one second-hand.
Read it as a young teenager, can recommend.
I'm seconding the recommendation to look at Rodnay Zack's books. For example, I really enjoyed Advanced 6502 Programming. It's a project-based tutorial for a custom 6502 machine. The design and schematics are in the book.
https://archive.org/details/Advanced_6502_Programming/mode/2...
WRT advanced 6502 programming texts, allow me plug my (free) book "EOR #$FF: 6502 Ponderables and Befuddlements". It's 64 assembly snippets to ponder, with explanations for each in the 2nd-half of the book: https://archive.org/details/eor6502
Seconded. I bought the first edition of "Programming the 6502" way back in the neolithic, and I enjoyed it greatly. I even read parts of it again now and then these days too, just because I like it. I used to write assembly on, at first, the AIM-65, and later the Apple II.
Is Programming the 6502 enough to learn Assembly on the Apple II ? But it doesn't explain the memory and screen management, right ? So how can we learn that ?
Someone can correct me if I'm wrong, but I believe the screen memory of the Commodore machines (ViC-20, Commodore 64) were the most straight-forward. As opposed to the more janky Apple II memory map.
You could do a lot worse than picking up a new Commodore 64 Ultimate [1]. They're a more or less faithful remake of the Commodore 64 but have an HDMI port, SD card instead of disk drive, etc. You could learn BASIC, should be able move to assembly as well—a quick search pulled up a YouTube course on 6502 assembly for the Commodore [2].
(I realize I am not contributing "books"—but others have done well in this regard. I did want to share what I think is a pragmatic way to learn 6502.)
[1] https://www.commodore.net
[2] https://youtube.com/playlist?list=PLU1o_YShTPgoA7_nZ0PutqaPD...
For that you'll need Apple II documentation - though that's device-specific information. It's easy to find online, e.g. https://nicole.express/2024/phasing-in-and-out-of-existence...., but there's lots more with various levels of info. This one, for example: https://www.kreativekorp.com/miscpages/a2info/memorymap.shtm...
For actual 6502 programming you'll need a dedicated 6502 assembly programming book, for example the aforementioned Rodney Zaks books.
Is the Apple II Reference Manual good for that ? Or anything specific to the Apple II, like "What's Where in the Apple" or "Understanding the Apple II" ?
All of those are quite useful.
https://mmphosis.netlify.app/hires/
> And is it absolutely necessary to learn BASIC before Assembly
If you don't have experience programming, learning BASIC before Assembly will be super helpful before you learn 6502.
If you only have experience programming in modern languages (Javascript, etc.), learning the Applesoft BASIC will also be super helpful before you learn 6502, as you'll learn how to get by without ...
A) the following language conveniences:
- function names (it's all line numbers),
- variables with more than 2 letters,
and
B) the following modern concepts:
- function calls (no stack other than for GOSUB, use subroutines with dedicated variables for passing parameters instead),
- scoped variables (everything is global),
- dynamic allocation (you have to DIM arrays with the max size upfront),
- anything object-like like structs or classes (hack it with multi-dimensional arrays)
- other fancy stuff like callbacks, promises, hashtables and any other data structure beyond arrays.
and that will nicely prepare you for 6502 assembly (or any kind of assembly really). The advantage in 6502 assembly is you can implement most of B) yourself if you do need it.
There are a few distinct things here. Learning 6502 assembly is straightforward, and you'd be better learning about simple (not modern) assembly languages at a high level--opcodes, registers, noop, branch, jump, compare, accumulators, program counters, and clock cycles. From there, start writing 6502 in an emulator and seeing what happens. That's where you're going to learn, and the feedback will be a lot faster. Programming for an Apple II will be more about learning how to interact with devices through memory.
When you say 'start writing 6502 in an emulator', do you mean a couple emulator like py65, and not a system emulator like Elkulator?
Two books for consideration.
Randy Hyde the creator of the Lisa assembler.
https://archive.org/details/A2_Hyde_6502_Asm_Lang/mode/1up
Ken Williams of Sierra OnLine fame.
https://vintageapple.org/apple_ii/pdf/Apple_II_Computer_Grap...
6502 Assembly Language Programming by Leventhal.
This is how I learned. This book is great. I have the worn paper copy sitting 6 feet behind me as I type this. It's worth getting a paper copy if that is still possible.
https://archive.org/details/6502-assembly-language-programmi...
Looks like a nice book, and it appears that he wrote books on other microprocessors (8080/8085, 8086, Z-80, Z8000, 6800, 6809, 68000... even SPARC apparently) as well. I'd like to find a full version of the 68000 book, which archive.org only seems to offer a preview of.
Love this. I had a copy 40 years ago.
The Apple II Reference Manual includes assembly listings (with full comments!) for the Monitor ROM and Autostart ROM, the mini-assembler, floating point routines, and a very nice 16-bit "pseudo machine interpreter" called SWEET 16. Most of which was written by Steve Wozniak. Learned a lot from this book back in the day.
Here's a link from archive.org. It's not the best scan, but you can easily find other copies.
https://archive.org/details/applerefjan78/page/n69/mode/2up
If you're feeling adventurous, you can find assembly listings for the AppleSoft BASIC language (though maybe only from third parties). It's pretty huge.
No, you don't need to learn BASIC before assembly, but many books of the time went that route, e.g.,
https://www.goodreads.com/en/book/show/5011686-apple-machine...
Here is an interesting article on porting a BASIC game for the Apple II to GW BASIC:
https://nanochess.org/akalabeth.html
and it includes a link to the documented source code for Akalabeth (also known as Ultima 0)
Somewhere, there's an article discussing the assembly-language like bit-blitting used to draw the high-res graphics in a timely fashion and the variable/memory management techniques needed to drive that which I'm sure a bit of searching will turn up (or one can derive it from the source).
They screen memory layout on the Apple II was a clever hardware hack but makes programming the machine more difficult. I think you'd be better off using a "trainer", like a KIM-1 simulator [0] to get your feet wet. (The KIM-1 was made by MOS Technologies, manufacturers of the 6502, as a demonstration and prototyping platform for the CPU.)
If you can do simple exercises on a machine like that and get comfortable with simple operations (loops, memory addressing modes) I think you'd have a better time grokking something more feature-filled.
[0] http://retro.hansotten.nl/6502-sbc/kim-1-manuals-and-softwar...
If you aren't doing hires graphics, you don't have to mess with the screen memory directly. You can just call the ROM routines which has the nice side effect of working with 40- or 80-columns automatically. If you are doing hires graphics you are going to use a lookup table regardless as doing the multiplication to get the base address of a particular scanline is far too slow. You can, one time, either make a table manually, which you can use forever, or you can write a short routine that counts from 0 to 191, stick 0 in X and the scanline number in A and JSR $F411. It'll leave the base address of the scanline in $36 and $37. Which you can stick in your table.
As in other comments, if you are specifically interested in the Apple II line, the Assembly Lines books by Roger Wagner is fantastic.
Also, if you can find it Sandy Mossberg's Disassembly Lines articles in Nibble magazine were great too. Start with Assembly Lines, then read the Disassembly Lines and you'll be quite expert.
I recommend these two books for 6502 assembly:
https://archive.org/details/ataribooks-machine-language-for-...
and
https://archive.org/details/ataribooks-the-second-book-of-ma...
These two books will give you a good understanding of 6502 assembler - it is general but gives a good background and has a nice assembler with a full walk through of the code. I used these two books to learn 6502 on my Commodore 64 and they are highly recommended.
These are great books. I had them in paper, and they were great for understanding both how the 6502 worked, and metaphors for managing higher level constructs in ML.
Don't overlook (if you can find them) books made for Commodore-64 assembly coders. (Same CPU.) While they won't contain II specifics, there were several that were very helpful with 6502 tricks.
[Off TOpic somewhat] This post made me immediately recall, the hours I spent playing Apple Invaders, 1979
Pinball Construction Set, by Bill Bludge
Chop Lifter, modeled on 1979–1981 Iran Hostage Crisis, Dan Gorlin, Brøderbund 1982
Castle Wolfenstein (1981) (Muse) by Silas Warner
Red Alert (1981) Olaf Lubeck, Broderbund
I still have some of these original games and the artwork in the shed.....
All classic Apple games of very early 80s
At the time, the programming was recognized as amazing, the sound and graphics. It was a marvel that it was achieved on such a low resource machine ....
Original Apple II manuals written by Chris Espinosa and Jef Raskin are a treat to read. Would highly recommend, just to get a sense of what it was like to get onboarded on Apple II back in the day.
And then obviously Programming the 6502 by Rodnay Zaks.
You don't need to learn BASIC first but it might be helpful for bootstrapping at the beginning. Since it's included in the computer you can PEEK and POKE memory locations from BASIC and get a feel for how memory and machine code works without needing to understand the whole entire hardware, bootloading process, etc. first.
In my opinion BASIC, with its line numbers and GOTO / GOSUB feels assembly-ish anyway - you'll be doing a lot of JMP / JSR to control program flow which is different to how modern high levels are normally written.
Learning BASIC isn't essential, but the thing is, you might as well just do it. It's not complicated, and you're not under any obligation to develop a big piece of software with it. Have fun!
RE "....Books to learn 6502 ASM and the Apple II...."
Suggest to look at some of the archives of old Apple Magazines from around the Apple I era , cira late 70s and early 80s.
Some of them would have had assembly language programming columns. I recall one Named Softtalk , but there where many. There are other Sites than Archive.org. Some archive sites solely devoted to early apple computers like Apple 2
I strongly recommend "What's Where in the Apple": https://archive.org/details/whatswhereinappl0000lueb I loved that book back in the day. Specific, directly addressable memory locations are mapped to system devices in a way that is quite foreign and Wild West when compared to modern computer architectures.
Targeting 8-bit Apple, Computes gazette published a stack of magazines and books especially introductory. Rodney Zaks did a bunch as well.
Personally I'd approach it using a raspi + python + pygame. Learn the fundamentals there then switch to apple.
There is "Apple Machine Language for Beginners" by Richard Mansfield https://archive.org/details/Apple_Machine_Language_for_Begin...
I have fond memories from the late 1980s of trying to get the assembler contained within this book working, typing line after line of the MLX listing in. Unfortunately I never did finish it back then.
A week or so ago I got the urge to complete this project and I literally just finished getting the source in it to a point where it can be compiled online and then within an emulator: https://github.com/jlmcgraw/LADS_DOS33
For learning basic, the question is: do you already know how to program?
Only reason I can think to learn basic is if you do not know any programming language. And even then there are better choices.
Do they make an C compiler for the AppleII?
Lance Leventhal's CPU books are pretty comprehensive and make it easy to switch from one architecture to another. Learning BASIC is definitely not a requirement.
Next to a book on 6502 assembly, you can google "apple 2 original system manual" and download it. I contains ROM assembly source code and schematics.
"reference manual" I think is what you mean. This is a link to a PDF pf the reference manual that includes the ROM disassembly: http://cini.classiccmp.org/pdf/Apple/Apple%20II%20Reference%...
I remember looking at the way graphics work on the Apple II and it looked pretty crazy lol with how memory layout worked to generate pixels.
Honestly if you want to learn retro stuff for retro reasons... maybe consider using the retro materials? Here's the MOS programming manual for the original parts, it's what Woz would have used when hand-assembling Integer BASIC:
https://archive.org/details/mos_microcomputers_programming_m...
And it's really not so complicated! The chip is simple, so the docs are simple. There's more to read about the history to come later, but there's also something to be said for understanding it in the context its designers presented it.
This one worked for me: Apple II 6502 Assembly Language Tutor (1983) Richard E Haskell
The answer would depend on what programming experience you have? Do you have any assembly language experience ? with other targets? ie have you used an assembler ( and maybe linker ) before. Are you familiar with hex? bytes, bits etc , You will learn this and much more ...
Id look for a book that targets Assembly programming on a Apple 2, ie not a book on general 6502 programming.
Hopefully the book would also provide guidance using a particular assembler ( hopefully still available)I googled phrase Apple 2 assembly language programming for beginners?
and lots of very good looking links popped up.
You aim is a challenging task. Much to learn. Good luck. However entirely do able these days.
My background is electronics engineer, embedded programing on in assembler (some Motorola processors and others) and C for a few years before moving on to other things ....
The book Assembly Lines: The Complete Book available as a FREE PDF download from .... site https://ct6502.org/product/assembly-lines-the-complete-book/
INCLUDES All 33 of Roger Wagner’s Assembly Lines articles from Softalk magazine, plus appendices, in one complete volume.
I have litteraly no programming experience, that's partly why I want to learn 6502 Assembly.
Assembly is a type of programming that is unlike most programming languages, and as such, would be a really tough introduction to the field.
Can you explain a bit more about how you became interested in assembly and programming the Apple II? And specifically, why you want to start the journey towards programming there?
Much easier to start with BASIC. After all, why not?
I respectfully disagree, BASIC/Java/Arduino hides too much about how the CPU works from users.
Getting a 6502 kit from Ben Eater, and walking though how the CPU works will implicitly show how languages abstracted away whats actually happening. And more importantly, the skills necessary to understand how to write efficient programs.
https://www.youtube.com/watch?v=LnzuMJLZRdU&list=PLowKtXNTBy...
https://eater.net/6502
Starting with a simple architecture is highly recommended. =3
I second this -- I just found the Ben Eater series a month or so ago and put together his computer clock over the holidays. It really helps you understand clock cycles, logic chips, etc, and is a good foundation for the 6502 kit you build later in the course. And learning Assembly before BASIC is the right learning path IMO, if only to understand how CPU registers work at the electron level.
If one is interested in how internal PC registers work, than these build series do the classic eeprom microcode based CPU builds. Fabian's series is highly accessible, and builds a python based assembler from scratch. James series ends with a simple game design.
Cheers, =3
"Build a Superscalar CPU" (Fabian Schuiki)
https://www.youtube.com/watch?v=bwjMLyBU4RU&list=PLyR4neQXqQ...
https://github.com/fabianschuiki/superscalar-cpu
"Making an 8 Bit pipelined CPU" (James Sharman)
https://www.youtube.com/watch?v=3iHag4k4yEg&list=PLFhc0MFC8M...
Starting with Assembly is simply a bad idea because the tooling is terrible, and the learning curve of the tooling is steep. Filled with arcane codes and abbreviations and workflow right out the gate.
Programming concepts are pretty much universal. Being distanced from computer architecture is not a limitation for novice programmers, Python et al succeeds for a reason.
If you're determined to start with assembly, then I hope you can find someone to help you get started with all the machinations necessary to get from LDA #0 to A9 00 with as little drama as possible. Someone to show you how to use the assembler, what the directives mean, the linker, a symbolic debugger (if you're lucky). Someone to provide you with a .DUMPREG "START OF SORT" and .DUMPMEM BUFF $80 "AFTER INPUT" macros that you can liberally scatter throughout your code so you actually progress and get some insight into what the heck you code is doing. Perhaps some way to stop your programs that doesn't include hitting the reset button on the machine.
I mention that because, again, the tooling is terrible. All of the is easier said than done. None of the assembly books address this, none of the assembly program reference guides do either. Assembly is VERY black box. It's a large step up to even get started.
It's much easier to "learn programming" first at a higher level, where you can quickly progress and succeed, before turning into the dark hole that is assembly, particularly on older machines.
At least on a KIM-1 you can hit the STOP button and cursor through memory (being conscious that the memory architecture of the KIM is quite funky), something that simple is quite difficult on an Apple ][.
In general, Assembly for a simple well documented CPU is fairly close to most familiar calculator operations, and is demonstrated as a 1 to 1 relationship in the binary firmware. If folks drop on abstractions like Scratch/Basic/Python/Java the students will develop a random notion of what Register/Stack/Heap even means.
I would recommend looking at a few random samples of Ben's build series, as he covers most first year subjects in subtle efficient ways.
Soldering kit PCB or Emulators are insufficient to demonstrate a physical bus wire harness, clock timing, and memory layout. Best of luck =3
Starting with the 6502 is going to bring you up hard against its addressing modes. Better IMHO to learn about memory and how to access it using arrays in BASIC first.
My opinion differs - learning how memory is accessed via assembly language will make it super easy to understand e.g. how C pointers actually work, something which can be surprisingly difficult for those who go directly to a high level (compared to assembly) language, but very easy if you come from machine code/assembly.
Depends on learning goals, as BASIC teaches people some really bad habits.
They say "one always ends up coding in whatever your first language was... regardless of what language you are using".
People could always bring up the BASIC software Rom at the end of the build if interest arises after learning how a simple computer works. =3
https://github.com/chelsea6502/BeebEater
If you have absolutely no experience with assembly then I'd suggest starting very simple with a modern microcontroller.
I have a special place in my heart for the original pic16f84a the modern equivalent is the pic16F1827.
Which uses the same 35 core instructions.
AVR8 is a close second.
Have you considered using something like claude code / opencode?