GEM 5.0 video driver
====================

  This zipfile contains source code for the one GEM/5.0 driver I know of:

Driver      | Resolution | Colours | Supported hardware
============+============+=========+===============================
SDPSC11.BS  | 640x480    | 16      | VGA 
============+============+=========+===============================

  This has been tested in GEM/5 and appears to work.

  Unlike the builds of earlier GEM drivers (but like the ones I did for GEM/4),
this driver isn't byte-for-byte identical to the original, or anything like. 
The original driver appears to have been built with a different assembler, 
but this was built with RASM86 v1.4a, just like all the other driver trees 
I've released. Whatever the assembler was, it generated different code for 
some AND and OR operations, optimised JMPs to JMPSes, and allowed the code 
segment to overlap with the data segment by up to 15 bytes.

  The major changes to the drivers since GEM/4.0 are:
* The C portions appear to have been built with a slightly later compiler 
 version. Some instructions are swapped over and there are various 
 optimisations.
* Some functions have been changed to use far (32-bit) pointers.
* The text output code is completely different. Most of it has been removed
 from the driver (relying on an external font scaler in the GDOS), leaving 
 only support for the builtin system font. The text drawing code has 
 accordingly been redisassembled.
* New function 147 - probably connected to text scaling.
* The "zyxg" area has got the 'long name' field back where it should be, as 
 it was in GEM/3.1.
* Various code which appears to have no purpose. Most if this takes the form
 of functions in copttxt1.a86, which appear to act as C wrappers but are 
 never called.  
* A debugger breakpoint (INT 3) at the start of the function I've called 
 "text_blt" in coptdraw.a86.
  
