Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!mailrus!bbn!bbn.com!kanarick
From: kanarick@bbn.com (Craig M. Kanarick)
Newsgroups: comp.sys.apple2
Subject: Re: Xapple2
Message-ID: <53134@bbn.COM>
Date: 7 Mar 90 15:55:50 GMT
References: <53040@bbn.COM>
Sender: news@bbn.COM
Reply-To: kanarick@vax.bbn.com (Craig M. Kanarick)
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 45

In article <53040@bbn.COM> I write:
>
>I just started writing an X application that would run all of
>the old Apple ][+ software (][+ because that is what I have).  I
>am interested in hearing from anyone who has performed a similar
>exercise.  I am also willling to send mail to anyone who wants
>to hear how I am going about it.
>
>-- Craig
>

Well, the response that I got from this posting was a little more than
I expected, so rather thatn mail back to all of you, I am just going
to post how I am going to do it.

Basically, I have written, in C, a 6502 emulator.  It has an array of
16-bit values, and is the memory of the Apple.  I also have 5 16-bit
registers, and a program counter.  Basically, the emulator is just a
big case statement, each branch being one 6502 instruction (yes, there
are a lot, because each instruction/addressing mode pair is a seperate
branch).  I am about halfway done with this part.  Essentially, I just
start by executing the instruction at memory[0] and continue down,
exectuting memory[program_counter].

When I get the emulator done, I will dupm the Apple ROM into my
Masscomp, and *poof*, I have an Apple.  Of course, I will have to trap
out any and all I/O, but this is not a big deal, since I only really
care about DOS, graphics, and maybe the paddle port.  Writing an X
interface is then the last step, also a rather mundane programming
task.  It shouldn't be too hard, no?  Just give me a few years.

One person has already volunteered to help, and I really appreciate that.
If anyone else would like to work on this project, let me know.  I am
doing this in my spare (yah, sure) time, and would love some help.  Maybe
we can really get this thing going...

-- Craig


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Craig M. Kanarick				"Do I love you?  Yes, I
kanarick@bbn.com				 love you.  All this talking,
		             			 talking, is only bravado..."
BBN Systems and Technologies Corporation	 - The Blue Nile
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