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What was the development toolchain for the Apple II/II+ like?


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#1 futlib   Members   -  Reputation: 197

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Posted 12 August 2012 - 12:55 PM

I'm wondering was game development was like in the late 70s and early 80s. One of the dominant systems back then were the Apple II and the Apple II+, so I'm specifically interested in that.

Can anybody tell me what languages, compilers, editors etc. were used back then?

Here are some specific questions:

- What languages were popular for game development? Based on my research so far, it looks like 6502 assembler was dominant, but there were different assembly languages, right? What about C, was it popular already? Any games written in BASIC?

- What compilers were available/common for the popular languages?

- How was code written/read? It looks like BASIC code was just written from the shell, adding instructions by prefixing them with numbers and LOADing, SAVEing and RUNning the programs. Was there no visual editor? Did you really have to use LIST n-m to look at your code? How about assembler/C code?

- How was input/graphics/sound handled? Were there any abstraction layers and APIs or did you have to talk directly to the hardware?

I'm also interested in anything else that was noticably different from now back then. Like how were images/sound stored?

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#2 phil_t   Crossbones+   -  Reputation: 3222

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Posted 12 August 2012 - 02:29 PM

I used to program on an Apple IIc back then. I used BASIC, which was pretty much as you describe. You input code through the shell, there was no visual editor (at least that I used).

I only wrote a few assembly programs (I was pretty young), and they were small and I was able to just convert them directly to machine language and input them via the "monitor". I'm not sure what the offical compilers were like.

From what I recall, I don't think C was used much. It was mostly BASIC and assembler. I assume most commercial programs were written in assembler. You could also call asslemby routines from BASIC, I think.

Sound support was limited to poking a certain memory address which would cause the speaker to click. Do it at the right frequency and a tone would be generated.

I forget exactly what the graphics capabilities were in Applesoft BASIC. I think they were pretty limited. I remember there were two graphics "pages" you could flip between so you could do double-buffered animation. Some information here: http://en.wikipedia.org/wiki/Apple_II_graphics#High-Resolution_.28Hi-Res.29_graphics

Manuals for the apple II: http://www.apple-iigs.info/doc/docii.htm
Have a look at the Apple IIe technical reference manual, it might have some interesting info.

#3 Ravyne   Crossbones+   -  Reputation: 6876

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Posted 12 August 2012 - 03:38 PM

C hadn't really penetrated the personal computer software market yet (in large part because that market had only just started with the Apple II and IBM PC, Atari and others) and the 6502 in particular is not terribly suitable as a compiler target because of its register-starved architecture.

Assembler and basic were pretty much it, and Basic was probably an order or two of magnitude slower than assembler. Its a safe bet that the overwhelming majority of Apple II software was written in Assembly.

#4 Twylo   Members   -  Reputation: 110

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Posted 31 October 2012 - 03:05 PM

Hi futlib,

I'm sorry to dredge up an old thread but I just stumbled across your question and wanted to chime in, especially because it's near and dear to my heart (I like retrocomputing, and was lucky enough to grow up in those days anyway)

In retrospect, it's kind of shocking how primitive the tools we had were. Things like IDEs and code editors for the home computer market just didn't exist. Around 1980, the only people using an environment that might even come close to the kind of things we're used to now were the LISP machine hackers and Smalltalk people at MIT, Stanford and Xerox PARC!

Although my parimary environment back then was the Commodore 64 (which didn't come out until 1982) I did get really familiar with the Apple II as well, so I'll try my best to answer based on my Apple II knowledge.

Can anybody tell me what languages, compilers, editors etc. were used back then?

Here are some specific questions:

- What languages were popular for game development? Based on my research so far, it looks like 6502 assembler was dominant, but there were different assembly languages, right? What about C, was it popular already? Any games written in BASIC?


There were a handful of games written in BASIC, but they were really just toys. Not even really "casual gaming" like today, but more like bad knock-off Mad-Libs style games, or very primitive copies of better known games. The kind of thing you'd buy, get home, start to play, and then wish you hadn't bothered. But they were very much the exception rather than the rule.

Assembler was absolutely the standard environment for game development, and any commercial game or application that was even half-way decent was written in assembler. At that time, C was still very much limited to the UNIX world, and UNIX was still limited to the PDP-11 and VAX. By the mid 1980s C and UNIX both started to make their way onto the desktop, but C just never made inroads into the 8-bit systems. It was too big, and the 6502 systems were too small and register-starved to make it worth while. (Ironically, there's a pretty good C tool chain for the 6502 these days called cc65! But it's a cross-compiler only, you compile and link on your big fancy Core i7)

There were several very common assemblers available for the Apple II. EDASM was the one offered by Apple, and I think it was written in-house by Randy Wigginton. Other very popular ones that I've used were the Merlin assembler, and the S-C assembler. They all produced 6502 machine code and of course they all used the same mnemonics for 6502 instructions, but their syntaxes had subtle differences in how you defined macros (if your assembler handled macros at all) and pseudoinstructions like ORG and EQU and so forth. But if you could use one, you could use them all with very little effort.

- What compilers were available/common for the popular languages?


Pascal and Forth were the only other languages on the Apple II that ever made any real impact. Pascal ended up being pretty popular, but not for games. And it was HUGE (for the time!) so you absolutely needed a two-floppy system to use it.

There were also the educational languages, like Logo. That was huge in schools. I think everyone my age was exposed to Logo in school at one point or another.

- How was code written/read? It looks like BASIC code was just written from the shell, adding instructions by prefixing them with numbers and LOADing, SAVEing and RUNning the programs. Was there no visual editor? Did you really have to use LIST n-m to look at your code? How about assembler/C code?


You're absolutely right on about BASIC - you just typed it in as you went and saved as many copies as you could while you were working on it. There was absolutlely no visual editor, you had to just LIST it a lot.

Assemblers were almost (but not quite) as bad. They all included code editors, but the editors were super primitive, and not really visual editors. They were really multi-line, line-oriented editors. If you made a mistake in a line, for example, you'd have to type "E 123" to edit line 123. And forget about inserting, everything was over-strike only, so you usually ended up just retyping the whole line. Ugh. Luckily, assembly lines were always very very short.

The real secret to being a good programmer in those days was to have a good printer. No joke! You really needed to print your source code and assembly listings a lot and then go over them with a highlighter and pen to debug it.

In fact, to be honest most initial development was done on paper anyway. You'd usually save a lot of time to just hand-write the assembly on paper, then type it in when you were close to what you wanted.

Things started to improve a lot by the early 80s, like '82-'83. By then people started to realize that they could use a word processor like Apple Writer or Easy Writer to write and edit their assembly. You'd have to be very careful to format it in a way that was compatible with your assembler, but you could use word processing macros and stuff to help you. That was kind of revolutionary.

- How was input/graphics/sound handled? Were there any abstraction layers and APIs or did you have to talk directly to the hardware?


Not APIs really, but there were some routines in ROM that could do some of the grunt work for you when it came to drawing lines, erasing screen areas, even rotating and scaling shapes. That helped a lot. But other than that, just cold bare metal! The 6502 used purely memory-mapped IO and a flat address space, so all intput and output was accomplished by reading and writing memory locations. There was no distinction between video RAM and main RAM - the video was driven right from pages of main memory that were mapped to the screen. So you could draw graphics by writing to this same memory directly. The Apple II didn't have sprites like the C64 did, or ROM routines for doing bitmap graphics, so you were on your own there.

It was a little quirky, though. You really had to know the nasty nitty-gritty details of the graphics hardware and NTSC timing to actually get good results out of it. I, alas, was never that good.

You know who WAS that good? John Romero! https://www.youtube....h?v=CRGLqYuZ1gA

Sound IO was even more primitive. You could do nothing but click the speaker. Seriously! You'd write to a memory location and it would click the speker. But hackers of the day were very clever and used duty cycling and loops to create some pretty cool sounds anyway. But that was as much of a sound API as you had: "Click the speaker... NOW!" (Here's where I get to plug the awesomeness of the Commodore 64 and its SID chip. But that's another story all together...)

Anyway, thanks for the trip down memory lane, and I hope this answers most of your questions! I still have an Apple II, I think I'll dig it out tonight and play with it Posted Image

-Twylo

#5 BeerNutts   Crossbones+   -  Reputation: 2669

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Posted 01 November 2012 - 08:35 AM

Twylo,

Thanks for the info. It was interesting to read. While I did write some BASIC on the Apple IIe and IBM PC jr when I was a kid, I didn't get into assembly until the 80286 or maybe 386. It's always good to hear some old stories, even when they start with, "Back when I started, we carried around our programs in shoeboxes holding punch-cards"
My Gamedev Journal: 2D Game Making, the Easy Way

---(Old Blog, still has good info): 2dGameMaking
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"No one ever posts on that message board; it's too crowded." - Yoga Berra (sorta)




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