A fun demo for the Dragon?

[tjewell]

(apologies if this has been asked before)

Well, my Dragon 64 is now sitting in the corner of the office, all wired up and nothing to do. I'd love it to be running some sort demo that makes people go "ooh, what's that?" when they come to see me. Perhaps something 3D and spinning, or pretty swirly colours - or even a game that has a good demo mode. Anyone know anything fun my Dragon could do while it's sitting there?

Thanks! Tony.

[Sarah]

Phantom Slayer?

[sixxie]

Trying to think of games with decent attract modes... I guess there aren't many - I always thought the music on Airball and Fire Force title pages are both good, but you don't want anyone actually *playing* Fire Force (Airball is great, though not an action game).

ROTABB's attract is reasonable (and the game itself very good). Manic Miner's at least runs through the levels. Oh and lo-fi but surprisingly playable: Cuthbert Goes Walkabout / Digging both have little attract mode bursts of game.

For demos there's a bouncing ball demo on a disk somewhere, I forget where though - I can try and find it if you have a disk system. Of course it's a 64, so if you have infinite patience, there's always this (*koff*).

[zephyr]

For demos there's a bouncing ball demo...

This is a cassette version of that demo.

[tjewell]

Thanks for your ideas everyone. Currently, I've got no sound on my Dragon (I've got it plumbed into a VGA monitor and don't have audio routed anywhere), so the Nyan cat is funny without being maddening! And thanks a lot for the bouncing ball, Zepher, that's perfect.

I'd never played ROTABB or Phantom Slayer before - both are rather good! ROTABB is getting rather addictive ...

Inspired by all this, I dusted off my 6809 primer and tried to recreate one of my first ever machine code programs - a simple kaleidoscope for the chunky graphics mode. Although some stuff came flooding back, I have forgotten so much in the last (nearly) 30 years! It took much longer than it should. Thanks to Sixxie for his perl assembler, which at least meant I could use a 'proper' text editor. I loved Alldream back in the day, but I think modern computers have made me soft - I found writing directly on the old machine just painful! Kids of today etc etc ...

Anyway, I am actually embarrassed to post this, but given it's the first Dragon program I've written for 27 years, and you all are the only people who'd understand why I found it such fun, I'm sharing it here! Do a CLOADM, then an "exec 20001"

Tony

Ps. Quick techie question - what do I do to avoid having to specify the exec address? so that simply typing 'exec' makes it run? for the life of me I can't remember!

[zephyr]

Inspired by all this, I dusted off my 6809 primer and tried to recreate one of my first ever machine code programs - a simple kaleidoscope for the chunky graphics mode. Although some stuff came flooding back, I have forgotten so much in the last (nearly) 30 years! It took much longer than it should. Thanks to Sixxie for his perl assembler, which at least meant I could use a 'proper' text editor. I loved Alldream back in the day, but I think modern computers have made me soft - I found writing directly on the old machine just painful! Kids of today etc etc ...

Anyway, I am actually embarrassed to post this, but given it's the first Dragon program I've written for 27 years, and you all are the only people who'd understand why I found it such fun, I'm sharing it here! Do a CLOADM, then an "exec 20001"

Nice to see you writing 6809 code again after 27+ years. Now you can write your own demo's and share them with us here at the forum.

Ps. Quick techie question - what do I do to avoid having to specify the exec address? so that simply typing 'exec' makes it run? for the life of me I can't remember!

CSAVEM"TITLE",Start Address, End Address, Exec Address.

[snarkhunter]

Hello,

Most of the time, you just do not have to type in the "Exec" address. That is, as far as the game was saved using all of the proper vectors, i.e. including the "Exec" address! You should try to "Exec" it first (EXEC <ENTER>). If that does not work and you know for sure your program is indeed machine-code, then you're in trouble!

That "Exec" vector has to be specified when saving a piece of executable code (i.e. using either the CSAVEM or the SAVE command). If not, then I believe a null address will be stored, which will most probably result in the Dragon crashing.

Otherwise, "Screamings Abdabs" and "Time Bandit" are among the games that have demo modes showing a lot of what's going on during game play, though maybe a bit too fast - no pun intended!

[tjewell]

Thank you! - attached now is a version of kaleidoscope that only needs an 'exec' to run after a CLOADM. Please don't get too excited

I was quite inspired by the guide to converting images via photoshop to load onto the Dragon - there must be an fun demo out there that I could write that uses that.

Thanks all for your help, and I'll take a look at the new games.

Tony.

[zephyr]

Some tips/suggestions:

(1) You can zero the A and B (D) registers using the single byte CLRA, CLRB rather than LDA #$00, LDB #$00

(2) Your program would be compatible with a 16K CoCo if you were to assemble it lower down at $0E00

(3) It would be a nice touch to be able to exit the program with the Break (or other) key

e.g.

Code: Select all

JSR   [$A000]
CMPA  #$03
LBNE  XXXX
RTS


Regards,
Steve

[tjewell]

It's quite addictive, this retro programming isn't it?

Okay, just because I can, attached is v3 of my little demo - this time with Steve's suggestions added, so you can now stop with Break/escape, plus more blocks and faster animation.

Cheers all!