Re: LF: 68K ASM Programming

Subject: Re: LF: 68K ASM Programming
From: Jimmy Mårdell <mja@algonet.se>
Date: Fri, 29 Nov 1996 21:44:07 -0800
In-Reply-To: <LF: 68K ASM Programming>
Ed Plese, Jr. wrote:


> 2.  When you get an address error, your program most likely tries to
> access a word or longword at an uneven address.  To access a word,
> the address must be evenly divisible by 2 and for a longword, I think
> the address has to be evenly divisible by 4 (maybe 2?)  To fix this,
> try changing the line to read or write a single byte instead of a
> word.


It must be evenly divisible with 2 if it's a longword.
 
> That's all I came up with so far, but if I come up with any more tips
> or things that may help other programmers, I'll post them.


I can tell the ppl on this list that I've almost finished my 68k guide,
that is an almost complete guide for Fargo programming. It requires that
you are familiar with assembly languages, because I've skipped explaining
many basic things that you can read in all assembly schools (like binary,
hex, twocomplement, registers, flags, memory addressing etc)


Here are the contents:


  0.00  ADMINISTRIVIA


  0.01  Contents
  0.02  Read this first!


  1.00  ABOUT MOTOROLA 68000


  1.01  Registers
  1.02  Flags
  1.03  How data is stored in the memory
  1.04  Some information about the instructions
  1.05  Effective address
  1.06  The video memory
  1.07  The stack
  1.08  How to use the libraries
  1.09  Fargo source template
  1.10  How to address variables
  1.11  Handles
  1.12  Highscores etc
  1.13  Common errors


  2.00  INSTRUCTION SUMMARY


  2.01  How the summary is structured
  2.02  Data movement
  2.03  Integerarithmetic
  2.04  Logical operations
  2.05  Shift and rotation
  2.06  Bitmanipulation
  2.07  BCD-instructions
  2.08  Programcontrol
  2.09  Systemcontrol


  3.00  MISCELLANEOUS


  3.01  Version history
  3.02  Greetings
  3.03  How to contact me




The instruction summary is the biggest part (and I have done about 1/3 of it) and
is taken from "Programming 68000" by Steve Williams - a book I recommend when learning
68k. The instruction summary is worth printing out until you're sure about what each
instruction do.


The first version of the guide should be finished tomorrow, saturday. At the moment the
text file is about 60k and about 1650 lines. I think, when the instruction summary is done,
it will be >100k, 3000 lines...


<pre>
-- 
Jimmy Mårdell                "Breaking your trust in sorrow, until you face
mailto:mja@algonet.se         the dreams of tomorrow, has taken place
http://www.algonet.se/~mja    Your life has been turning, inside your head
IRC: Yarin                    The truth will be burning, until your dead"
</pre>
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