I came across Meteor Storm and couldn't get it working under XE OS. Tried all sorts but it wasn't happening. MC was the only way, but my MC-fu is weak. Several hours later and I've found a memory move routine that works backwards (necessary in this case). Several more hours later and I've got it working after figuring out how to do addition in MC (very painful). A couple more hours and I've integrated it into the game and it is working fine, to my eternal joy.
This game refuses to work on XL/XE systems as originally printed. The reverse scroll of the meteors is achieved by fooling the OS into thinking it is in mode 0 when it is actually in mode 1, and then printing an insert line character at the top of the screen. While this works on the 400/800 OS, under the XL/XE it does something evil to the display RAM, corrupting it and making the game unplayable. To fix this, I have added a small MC routine to replace the print of the insert line character. The MC routine detects the address of the start of screen RAM, and copies lines 23-3 to the next line down in reverse order. A normal memory move wouldn't have worked as the source and destination overlap.
And here they are; bootable ATR (Basic required), and the BAS and LST (as a TXT) files for your pleasure. Enjoy!
PS, Atarimania are more than welcome to add this to their database as a fixed version.
Edited by NuY, Tue Aug 13, 2013 7:43 AM.