I updated the file.  You can try it again if it failed before.  I don't know if this will fix it, but I'm hoping it does.

Actually, you can do this with a 3D TV now that I think about it if the shutter glasses are modified to flash on and off at different phases... and you can get full color with that and its not bad for your eyes.  THAT would be cool.  Don't have any hardware to make tests for it though and I'm pretty sure the glasses are only able to alternate the shutter and not have both on or both off.

I just found this on my computer, it was a project I started a long time ago to test this really neat idea I had.

Basically, when you're not playing online, a 2 player FPS games on a console has to split the screen into separate regions for each player (splitscreen).  That reduces the overall room you have to look around in on the screen.  Another think that happens, is that its very easy to glance at your opponent's screen which gives away hiding positions and other location information that generally makes some games hardly as fun and much less strategic.  So I thought up a method that would solve both of these problems at the same time!

I call this new invention of mine Chromatic Multiplexing.  The way it works is that both player's screens are drawn on top of each other filling up the entire screen.  One player's screen is drawn in red monochrome while the other player's screen is drawn in blue monochrome.  Then, each player wears special filtering glasses to only see their screen and block out the other one.  I have included instructions on how to make filter glasses if you have any of those useless Red-Blue glasses laying around since those are pretty obsolete these days.  The colors seem to filter best on a CRT monitor I think, there is a little bit of ghosting on my LCD, but both should work fine and are certainly playable.

I made a 3D Tank game to test this and its surprisingly fun if you have a buddy you can play with.  The controls are the arrow keys for the right player with the right Ctrl to shoot.  ASDW keys for the left player with left Ctrl to shoot.  The game is for Windows and should work on XP and above.  It requires DirectX9 but I think it might install the dependencies for you if you're missing any, I'm not sure.

Anyway, Enjoy!

Actually scrolling up would be Copy()^r (reversed) and only if the width of that last column is exactly 8 pixels.

Although it might just be easier to just redraw those sprites, especially if you don't need smooth scrolling.

I'm confused why that code is any different than the current code:

"A and B"
ld hl,(var_a)
ld de,(var_b)
ld a,l
and e
ld l,a

It returns 0 if its false and non-zero if its true as well, and its the same size.  Unless your optimization is a speed optimization?

And Ikkerens, that code has always worked.

I forgot to mention, you should ram clear before installing Axe 0.3.1 if you upgraded from 0.3.0 becasue the hooks are different.  That might explain any one time freezing from unrelated events.

DJ, I don't add checks becasue its a waste of memory.  Its up to the programmer to add checks themselves before the actual appvar is created.

Don't know if it has been asked before, but do you plan to support music and sounds for the game?  It might just be too much data for the already crowded app, but it sounds like it could be possible since you said you weren't using all of the clock cycles and in 15MHz you could get some decent quality.