Hello, Assembly

2008 October 22
tags:
by JJ Sonick

As well as a attempting a simple RPG in BASIC, I’m also getting my feet wet with Assembly.  I have two main goals with Assembly, ones that cannot be reasonably achieved with BASIC:

  1. Sound creation and manipulation
  2. Tile-based graphic scrolling ala the early Ultima games.  Even as I’m coming to general grips with Apple II graphics, I have no idea how this was done, so I’m curious to explore it.

An ultimate goal with tile-based scrolling would be do make some sort of super-simplified Starflight clone (I was always jealous that Starflight didn’t exist for the Apple II) — but that is REALLY pie-in-the-sky – I’d be happy just make a successfully little one-area demo. ;)

I’ve just started “Assembly Language for the Applesoft Programmer” by Finley and Myers, and it seems pretty well written.  Despite the title, it’s not about just getting some binary programs to run from your BASIC programs, it’s more a full-on assembly tutorial aimed at weaning a programmer away from BASIC and into pure assembly.  Assembly’s making sense so far, a lot of which is probably due to my working through the wonderful book Bebop Bytes Back 6 years ago or so.

I’m using the Merlin assembler, which seems to have a very friendly environment, and I’m delighted it allows the entry of decimal numbers, which I’ll be using to “cheat” as much as possible (sorry, purists).

One alarming thing: there was a typo in one of the early sample programs in the “Assembly Language for the Applesoft Programmer” – a typo that was in fact repeated twice.  The program was simple enough that I was able to spot it immediately, but it makes me worried about the longer, more complicated program listings – I might not spot the typos so easily there, which could lead to lots of frustration.  If that becomes a problem, I may have to switch to some other book, which would be a shame, because I like the clear writing in this one.

5 Comments leave one →
2008 December 11

You may want to check out the archive of retrobits podcast (iTunes has it). There was a rather good overview of assembly language.

2008 December 21

Thanks, Adam! I’ll be sure to check that out.

2009 March 20

Hi. Mr.Sonick

I understand that you are using merlin assembler for your coding.

I’ve been searching for a manual of merlin assembler, and google brought me here.

Do you happen to have a pdf or txt of it?

By the way, I love your screen shots taken by camera. The blur looks cozy and retro. Lovely.

2009 March 23

Hi Chang E. I found text files of the docs (split into separate chapters) on an Apple II disk image, and extracted them with Cider Press. I’ve zipped up those txt files for you here:
http://www.mozomedia.com/apple2/downloads/merlin-doc.zip

(Chapter 8 was missing from the disk image, but seems non-essential)

There’s also other docs on the Textfiles Apple II pages, if you scroll down to the M’s:
http://www.textfiles.com/apple/DOCUMENTATION/

Glad you like the pics!

2009 March 24

Thank you, Mr. Sonick.

I’ve downloaded from your archive.

And now I can escape from edit-mode on merlin. :)

Thanks again and wish your happy adventure !

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