64K Screen Loader

By Jonathan Harston

Originally published in EUG #72

One of the more popular expansions for the Acorn Electron was the Slogger 64K Master RAM Board which doubled the size of memory available to applications like View - and made some Mode 7 adventures for the BBC able to run on the Electron (in Mode 6).

However, one of the big disadvantages of enabling the board expansion was that the screen memory in the original Acorn Electron memory map (between &3000 and &8000 in Mode 1) could no longer be directly accessed. This meant that for almost all arcade games the board had to be switched off. Although much mitigation was done at the time with Slogger protesting that only software which illegally writes directly to the screen will not be compatible, this was frankly all of it. Every loading screen on every game was simply *LOADed to screen memory - so on an 'upgraded' Electron instead of that graphical masterpiece, all you got was a blank screen.

Until, that is, now. 64KLOAD is a short machine code program by Jonathan Harston that can force any images loaded to screen memory to appear on-screen in 64K mode. Load the file 64KLOAD and change the filename in line 210 to change it to work with your own picture file.

Needless to say, don't load this on a Beeb - it will hopelessly confuse the Operating System and result in a big crash from which your computer may never recover. ;-)