MEM C800h:1C00h - IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. XGA(Extended Graphics Array), XGA(Extended Graphics Array)/A - MEMORY-MAPPED REGISTERS
Range:	any 8K boundary within segments C000h to DFFFh
Notes:	The XGA(Extended Graphics Array) memory mapped registers can be assigned to the last 1K block in
	  in each 8K block in the range of C0000h-DFFFFh; the base offset of
	  the 128 memory mapped lcoation for a particular XGA(Extended Graphics Array) instance is
	  Segment:(1C00h+instance*80h) for each XGA(Extended Graphics Array) installed in a system
	  (default instance is 6).  The instance number may be read from the
	  XGA(Extended Graphics Array)'s Programmable Option Select registers
	The XGA(Extended Graphics Array)/A (PS/2IBM PS/2, any model adapter) uses the 7KB area below the memory-mapped
	  register area for ROM(Read-Only Memory) A memory for program storage which may not be changed by the program as it runs. data; the XGA(Extended Graphics Array) (PS/2IBM PS/2, any model onboard) has included
	  this area in it's video BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. ROM(Read-Only Memory) A memory for program storage which may not be changed by the program as it runs..
	Most of the memory mapped registers are from the graphics coprocessor,
	  while the I/O-registers are for the display controller.