🚀 go-pugleaf

> Ok, the standard mode 13, 320x200 is very restricted, but it is possible
> to kludge this mode, in a similar way to creating modex, so that
> ALL 256k can be accessed, the screen can be scrolled, and therefore
> flipped, which is just scrolling by a 'page'.  You can change the
> logical width of the screen, you can use set address high and low
> to scroll.  I posted a demo that does all of this...accesses ALL
> 256k, creating a 512x512 virtual screen, and pans around it.  Someone
> who has it may want to post it, or I'll get to it this weekend.
> 
> This may be splitting hairs, I know I'll get flamed because the
> original question was about mode 13 and not a derivative, but
> if you're going through the trouble of using modex, you may as
> well have a choice.  Modex gives higher resolution, but mode13
> gives more free memory for storage of bitmaps and such.

Any mode that accesses all of the VGA card's 256k has a setup similar to ModeX
or the EGA modes.  I recall looking at that demo, and it set up a pseudo-modeY. 
I'll have to look closer before I say more about it, but it was not a mode 13h
and I believe it did require the plane 0, byte 0, pixel 0, plane 1, byte 0,
pixel 1, etc., format.  If it didn't, then I'll have to use your mode.

I do, however, believe you are referring to ModeY, the 320x200x256x4 page mode. 
Mode 13h is just a 320x200x256x1 page mode.

Josh