Hi,
There are numerous langages to code an Amiga OCS. But three share the most part : Asm 68K, C and Amos.
Amos is a kind of basic dedicated langage made to use the extraordinary graphics and audio skills of the Amiga.
I personally coded some little things with Amos and you can find some sources here (and an ADF with Amos Pro itself).
I think Amos was first designed for the A500 so with 512kb of Chip memory.
The challenge here is to code a demo (I mean in the sense of demoscene) for ALL the Amiga, so in fact for the A1000 which has only 256kb of chip memory in standard.
So I tried to do a very simple test : simply one bitplane of 320x200 (so 2 colors) that displays the available chip memory in bytes.
It gives that :
Less than 30kb of free chip memory !!! Less than the "graphics" memory of my Amstrad CPC (which is a cool computer that I got for Christmas 86) !
And I use some instructions to save memory (Close Editor, Set Buffer ...) otherwise the code didn't even work (out of memory)...
I think I can play with some other parameters like the size of the copperlist (12kb by default if I remember well). But it is too low.
Ok it is impossible with a standard Amos pro config to do a demo with a total memory of only 256 Kb.
So the challenge becomes "doing a demo for A1000 with Amos with only 256Kb of chip and a bit more of total memory".
I don't know what kind of memory extensions were usual at the time : 256kb extra chip ? 512 kb extra slow like the 500 ? Other memory ? No extension at all ? If someone knows, I am interested.
Anyway I hope that all the existing used A1000 config have at least a small extension, of any kind, so that the total memory is at least 512kb.
I tried two configurations.
First an A1000 with 256kb of chip, 512kb of slow (cannot set less with winuae). It gives that :
So about 145Kb of chip memory.
Secondly an A1000 with 256+256kb of chip memory. It gives that :
So about 285Kb of chip memory.
Conclusion : my demo must work with max 145kb of chip available free memory.
Not a lot, but sufficient I think to do some interesting scenes. I will try some simple things soon.
See you
Aghnar