Stairway To Hell webmaster Dave M, now also of Retro Software, asked me some time ago if I could design an opener for its range of games, preferably in the style of Superior/Acornsoft.
The result is this little loader program, which can be CHAINed at any reasonable PAGE value, and maps a graphic of the 'Retro Software' logo directly onto screen memory. The program uses a useful trick, in that it is actually a BASIC program, which sprite data 'tacked on' the end.
Dave M originally wanted the LOADER to be adaptable, so that he could just stick in a PRINT "THE TITLE" command somewhere in the listing and the title would appear in the correct place. This can be achieved by typing:
45PRINT SPC(x);"THE TITLE"
to ensure the title is centred.
However, because the sprite data is stored the way that it is, you cannot then simply SAVE the 'new' loader with the normal SAVE command.
Instead you need to use the following, assuming that PAGE was &E00 when you loaded the original code:
*SAVE <filename> 000E00 +9F0 FF804B
This saves the BASIC program and the sprite data, and ensures that you can CHAIN the resultant file as you would expect!
1st January 2009