Date: Wed, 25 Sep 1996 15:40:45 -0700 (PDT)
From: Samuel Vincent <svincent AT cs DOT sonoma DOT edu>
To: Ian Chapman <ichapman AT nortel DOT ca>
cc: djgpp AT delorie DOT com
Subject: Re: HELP: low-level programming necessary ?
In-Reply-To: <32492C53.268E@nortel.ca>
Message-ID: <Pine.GSO.3.94.960925153403.25074A-100000@zippy>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Wed, 25 Sep 1996, Ian Chapman wrote:

> Hi,
>      I'm not too sure what is involved in learning Assembler for a 
> 486.  I started on more primative m/c's.  Try getting a 6502, 8080, 
> Z80 or 6800 manual and figure out some of the examples first.  I think 
> with a 486 you have to get the 8086 section running to set up the  
> segmentation and I do not know whatelse.
> 
>      Regards Ian.

Say what?  Assembly is not really that hard.  You have these registers,
kinda like those little memory cells in your calculator.  And you have
a few instructions that manipulate things.  Like:  addl %ebx, %eax
which will add whatever is in the ebx register to the eax register.
"addl" meaning add long..  or 32-bit add.  Quite simple really.
The only thing is since most things in assembly use registers,
you don't always get to use nice self-explanatory variable names..
You use the register names instead.  So, lots of comments on what you
are doing is a must.  Aside from that it's almost like C.

Just get a book that tells you all the registers, and all the opcodes.
(It will probably teach you in Intel assembly style.)  Learn the AT&T
assembly style (not a whole lot that's different, just looks different.)
My example above was AT&T syntax.  IMHO assembly in a 32-bit flat
addressing environment is a great deal easier than in a 16-bit
segmented addressing environment (real mode).

-Sam