Programming Forum
Cell Wall Rebound
homebrew games. I have looked everywhere and googled every possible
search combination to no avail. I am very interested in developing
homebrew for the vectrex but, really need a forum/group that is very
active and specializes in discussion of development of the games
themselves such as code help and such. Any assistence would be greatly
appreciated.
Sincerely,
Cell Wall Rebound
FURY
wrote:
This is it.
There is some help out there, in the form of 2
tutorials by Chris and Chris. Just type "Vectrex
tutorial" into Google and they should come up.
Manu's page has some small coding examples.
Type "Manu Vectrex" into Google.
You're going to need to sit in front of your pc
and work your way through it via trial and error.
When you hit a brick wall, you can post a
question here.
Good luck
George
Roberto Nerici
> On Sep 14, 9:55 am, Cell Wall Rebound <cellwallrebo...@gmail.com>
> wrote:
>> Can someone please direct me to a forum for developing vectrex
>> homebrew games. I have looked everywhere and googled every possible
>> search combination to no avail.
As you will understand from George's reply, there's nothing wrong with
your googling, it is just that there isn't any forum like you are
looking for.
>> I am very interested in developing
>> homebrew for the vectrex but, really need a forum/group that is very
>> active and specializes in discussion of development of the games
>> themselves such as code help and such. Any assistence would be greatly
>> appreciated.
> There is some help out there, in the form of 2
> tutorials by Chris and Chris. Just type "Vectrex
> tutorial" into Google and they should come up.
> Manu's page has some small coding examples.
> Type "Manu Vectrex" into Google.
Seconded. If it helps, this is a good place to find Chris Salomon's stuff:
http://www.playvectrex.com/designit/chrissalo/toc.htm
I've found it very useful.
But to really answer your question, the only place to post is here.
There's a few people who've written stuff here (e.g. George). More
personally, I'm dabbling with programming the Vectrex so I'd be
interested in anything you have to say or ask about programming the
Vectrex, even if I cannot promise yet to be able to help.
Roberto/.
Cell Wall Rebound
Thanks, my first question is what is how do i create varaibles for my
game? I know in the atari 2600 you create variables starting at memory
address $0080 using name(myvariable) .ds bytes(1/2/3) etc. Can someone
please point me in the right direction?
Sincerely,
Cell Wall Rebound
FURY
>
> - Show quoted text -
Again, here's the link to those tutorials:
Roberto Nerici
> game? I know in the atari 2600 you create variables starting at memory
> address $0080 using name(myvariable) .ds bytes(1/2/3) etc. Can someone
> please point me in the right direction?
I recommend you look at previously mentioned tutorials and resources to
get started, but in the meantime...
The Vectrex's total address space runs from $0000 to $7FFF, i.e. 32k.
However most of that is normally for ROM, either the built in BIOS (or
"Executive"), or a game cartridge. The Vectrex has 1k of RAM which is
mapped to $C800 to $CBFF, which is what you're interested in.
Now some of that is used by BIOS routines so shouldn't normally be used
by us mortals. According to Chris Salomon's tutorial "Appendix B: BIOS
RAM locations", $C880 to $CBEA is the safe area to use.
Short answer: use $C880 onward, rather than $0080.
As for how to do this in code, it might depend slightly on the assembler
you use (I'm using the Kingswood assembler; everytime I've seen someone
on r.g.v say which assembler they're using it is this one, so if nothing
else this is traditional among Vectrex developers!) However the basic
technique, in my basic dabblings anyway, is to declare something using
an 'EQU' statement:
myvar EQU $C880
myothervar EQU $C880
Then you reference the variable such as:
foo:
LDA myvariable
ADDA #64 ; add 64 for no good reason
STA myothervar
Hope this helps! Other people, especially those who've actually written
something for real, are welcome to correct any falsehoods I've made...
Roberto/.
References:
http://www.pelikonepeijoonit.net/vec/
http://www.playvectrex.com/designit/chrissalo/toc.htm
http://www.kingswood-consulting.co.uk/assemblers/
Kokovec
helpful.
Also, you'll want to keep a 6809 programming reference manual handy.
Roberto Nerici
> I found that walking through existing disassembled programs was very
> helpful.
Any in particular? I've found the disassembled BIOS interesting
(although I don't pretend to fully understand it) but I've not looked at
any disassembled games.
Another program that could be useful is the source code for Ville
Krumlinde's Thrust. He kindly made it available along with an
explanatory introduction:
http://www.emix8.org/static.php?page=VectrexThrustSource
I've not made use of it yet, but I think it will be a good guide to how
to write a real program. He seems to have some good techniques in there.
It's a brilliant game too!
> Also, you'll want to keep a 6809 programming reference manual handy.
Yup. I've got the offical one, but actually use a book by Lance Leventhal.
Roberto/.
Kokovec
>
> Yup. I've got the offical one, but actually use a book by Lance Leventhal.
This one is my favorite: http://www.amazon.com/Assembly-Language-Programming-Lance-Leventhal/dp/0931988357
Roberto Nerici
>> Yup. I've got the offical one, but actually use a book by Lance Leventhal.
>
> This one is my favorite: http://www.amazon.com/Assembly-Language-Programming-Lance-Leventhal/dp/0931988357
Such taste :-) Mine has a different cover but I think it is the same one:
http://ripsaw.cac.psu.edu/~mloewen/Oldtech/Tandy/6809-L.jpg
I do have one by Rodney Zaks too but I haven't used it.
Roberto/.
Cecil Casey
look at to find books you would be interested in.
Good Luck...
-Cecil
http://www.worldcat.org/search?q=su%3AMotorola+6809+%28Computer%29&qt=hot_subject
On Sep 18, 3:02 pm, Roberto Nerici <r...@bloggo.org> wrote:
> Kokovec wrote:
> >> Yup. I've got the offical one, but actually use a book by Lance Leventhal.
>
> > This one is my favorite:http://www.amazon.com/Assembly-Language-Programming-Lance-Leventhal/d...