Event Block Effects

[AMSDOS]

This demonstration program was in Australian Edition of Person Computer Games Vol 2 No 8 November 1985. It was an absolute pain in the butt to get anything working out of this, in the end I've removed all the REMs which were stuffing up the program for some reason, the Initialisation was pointing to a REM line, so I changed that to a line looked more appropriate, I scraped the M/C from the BASIC program and used the Assembly which was provided and located in a different spot (it looked as if the original M/C was writing itself over the Disc ROM area I think. So now it works on the 464.


I tried to get this program working on a 6128 as well, though I'm unsure why it's not working. The Assembly shows a 464 address is used for the BSTART label - being &AE81, the 6128 equivalent being &AE64 (according to the Firmware Guide), though the program only crashes with this. Further into the program another address is used to initialise the Event Block which is some ROM specific routine, I'm guessing that maybe this is different for those machines, though I'm not 100% sure.

[TFM]

Funny stuff! It fills the screen with a pattern, then a line of one repeated character appears, then it starts FutureOS *hehehe*. I like it!

[AMSDOS]

Funny stuff! It fills the screen with a pattern, then a line of one repeated character appears, then it starts FutureOS *hehehe*. I like it!

If that is the 6128 version you tried, then unfortunately that's the version which is crashing. FutureOS doesn't work on a 464 does it?

[TFM]

You are right (two times).
So by accident the crash was probably jumping in one of the FutureOS ROMs (which were connected, but deactivated. I only had ROM 0 and 7 switched on when I started the 6128 version).

[AMSDOS]

I forgot to mention there's a bit of an article which went with this demonstration which was recently uploaded to the Wiki:

http://www.cpcwiki.eu/index.php/File:PCG_p36.jpeg
http://www.cpcwiki.eu/index.php/File:PCG_p38.jpeg
http://www.cpcwiki.eu/index.php/File:PCG_p39.jpeg

It looks like it's an early Aunty John program if I'm reading the Authors name correctly.

What the demonstration shows is 3 ways of clearing the screen, after the patterns have filled the screen, they proceed to clear, the first begins from the centre and works outwards as a box, the second merely clears from bottom to top, fairly clearly & the last works from the middle though in a jagged staircase like manner.

It's interesting I guess, though very complicated & there is probably better examples out there which might work on all the machines and to be honest this program was extremely difficult to get working and I ended up taking all the REM statements out of the program because that seemed to be messing around with the program too. I think the reason may have something to do with the Interaction between M/C & BASIC code and initialising ROM based stuff which isn't something I know much about.