GEM 2.2 video drivers
=====================

  This zipfile contains reconstructed source code for the following GEM/2.2 
video drivers. The drivers fall into three categories:

1. Drivers which I can compare to the original GEM 2.2 drivers, to be sure 
  they exactly match.

2. Drivers for which I haven't got the original, but which I can test. These
  may not be the same as the originals, but it's a good bet that they work.

3. Drivers where I haven't got the original and can't test, so I've no idea
  if they even work.

Driver     | Category | Resolution | Colours | Supported hardware
===========+==========+============+=========+===============================
SDATT7.EGA |        1 | 640x400    |  2      | AT&T 6300, Toshiba 3100
SDCGA7.CGA |        1 | 640x200    |  2      | CGA and compatibles
SDDEB7.EGA |        1 | 640x400    | 16      | AT&T 6300 Display Enhancement
SDEH87.EGA |        1 | 640x350    |  8      | EGA colour
SDEHF7.EGA |        1 | 640x350    | 16      | EGA colour
SDEHM7.EGA |        1 | 640x350    |  2      | EGA mono 
SDELF7.EGA |        1 | 640x200    | 16      | EGA colour with CGA monitor
SDGEN7.VGA |        3 | 1008x728   |  2      | Genius card
SDHRC7.EGA |        1 | 640x350    |  2      | Hercules
SDP647.VGA |        3 | 640x480    | 16      | Quadram Prosync
SDP757.VGA |        3 | 752x410    | 16      | Quadram Prosync
SDPSC7.VGA |        1 | 640x480    | 16      | VGA 
SDPSM7.VGA |        1 | 640x480    |  2      | MCGA 
SDWYS7.VGA |        3 | 1280x800   |  2      | Wyse 700 
===========+==========+============+=========+===============================

  Note that I've retained the GEM/3 driver naming convention; the real GEM/2.2
drivers have names ending in .SYS.

  The originals of the SDPSC7 and SDPSM7 drivers come from a different source 
than the others, and appear to have been built from a slightly different fork 
of the driver source tree:

* The q_circle array, used to draw rounded ends on thick lines, is only 21 
 words long. In all other drivers I've studied, it's 40 words.
* The mouse driver appears very similar to the GEM/2.1 mouse driver with 
 added PS/2 support. This doesn't match the revision history of the mouse 
 driver in the published GEM/3 source, where PS/2 support was added only after
 support for Concurrent DOS.
* The VGA font is the same as the one in GEM/2.1, rather than the version 
 used in other GEM/2.2 drivers.
