asm68c Files

This directory contains the fig FORTH model source code for the 6800.

The license for the fig FORTH model source code is specified in the 
source code files. It appears to be similar to the MIT, BSD, or ISC 
licenses, and the FORTH Interest Group and community have traditionally 
treated it as such. Although there is assignment to the public domain, 
copyright is claimed, and attribution is specified as a condition of 
distribution, use, etc. Aside from the reference to the public domain,
the intent does seem clear, and I am following my understanding of the 
intent in making it available here. 

I do not intend my interpretation and the example I set by it to be 
legal advice. If you redistribute the assembler, you may prefer to 
keep the fig FORTH model source code separate.

Using the model is fairly straightforward.

Get Joe Allen's exorsim project from the sourceforge repository:

    http://sourceforge.net/projects/exorsim

Make it in some appropriate place on your workstation computer.

Make a blank disk image with something like

    dd if=/dev/zero of=zero.dsk bs=128 count=2002

If you haven't yet downloaded asm68c, do so. I recommend either 
using git directly (clone read-only is easy) or getting the 
snapshot tarball via the git repository web pages. The 
downloadable files will always be several steps behind, because 
I always forget something. 

Where you get the snapshot tarballs -- when you are looking at 
the developer web pages at 

    http://sourceforge.net/projects/asm68c/

you'll see the link to the Git repository up there with Summary, 
Wiki, Files, Guestbook, and Discussion. Click the link to the 
Git repositories. Click the link to Code if that page opens up. 
(a68c-Code is a dead branch for now, I should remove it.)

You'll get something of a birds-eye view of the repository. 
Above the line showing the git command for getting a read-only 
clone, over to the right, will be three links, including the 
History and the Feed. Click the "Download Snapshot" link and 
your browser should offer to save the tarball.

(Incidentally, the source files can be browsed on-line at the 
git repository web pages I mention above. If you only want, 
for example, fig-forth_crlf.68c, just browse to that page.)

Make the asm68c project in some appropriate place, and then do 

    make fig

Open the exor simulator object output, "fig-forth_exorsim.x" in 
a text editor, select all, and copy. (Yes, S1-S9 object is ascii 
hexadecimal, and very readable with a text editor.)

Run exorsim with

    ./exor -x --mon zero.dsk

(The modified model doesn't actually access the disk image "zero.dsk" yet, 
but having the image reduces the complaints.)

Use the debug monitor's (single-"l") "load" command:

    l

and paste (right-click) the object code into the shell window. 
When the code finishes loading, hit control-C to end the load 
function. 

(If on MSWindows under Cygwin, you may need to click the icon 
in the top-left corner of the title bar to get at the copy/paste 
functions. I'm not sure, I haven't used Cygwin enough yet, but 
MinGW is that way, just like the current MSWindows shell.)

(No, MinGW does not have enough of the Linux API to run exorsim.
I hear that Cygwin does, but I haven't tried it yet. Besides, you 
really, really, really want to try out dual-booting a Linux 
distribution anyway. MSWindows is just so last-century. ;->)

Use the 

    c

("continue") command to start.

If it says something about an unknown record, be sure you've 
hit ctrl-C to break out of load mode, and try the "c" command 
again.

It should respond with a Forth-68 prompt, after which it will 
accept FORTH commands.

There is some debugging stuff still in there, but it will execute expressions and compile colon definitions.

For more information on fig FORTH, see http://www.forth.org .

Look, in particular, for the installation manual, the model source 
pdf files, and the glossary.txt file, which is something of a 
technical manual for fig FORTH.

Enjoy!



(For MSWindows users:

About trying out Linux, maybe I'm not completely serious, but
I'm more than half-serious. It's still not a smooth ride, but 
you'll save yourself serious grief down the road by doing it now.

David L. Jaffe at forth.org brought the end-of-line character 
issues to my attention.

For this project, the source code is in unix format. I apologize, 
but I have other things I want to do with my time. 

Line-ending characters are such a minor nuisance, but they are 
an example of one of the little gotchas that the folks at 
Microsoft are all too happy to avoid doing anything about, 
especially if it keeps you locked into their world, paying them 
for your next updates, following their rules.

Having said that, MinGW and Cygwin (and *nix) have a unix2dos 
tool that can be used to fix the line-ending characters in the 
source for you. I don't remember whether you have to explicitly 
install it or not, but it's available. Use the command like 
this: 

    unix2dos fig-forth_exorsim.68c

and it converts the file in place, and then you can open it with 
Notepad.

You used to be able open a file with unix line-endings in Wordpad
and save it as a text file, but I think Microsoft has decided to 
make the speed-bump on that work-around a bit higher lately.

One thing I've done now, I've added fig-forth_crlf.68c to the 
repository. It will be a copy of fig-forth.68c with the crlf 
line endings, so that, at least, can be read with Notepad as is.

End-of-note-to-MSWindows users.)