Mitsubishi Electric Apricot XEN pentium Owner's Handbook Manual page 127

Inside your computer
Note
The top location of this first Mbyte is 1M-1 or FFFFFh. This is because
in the first Mbyte there are 1M locations, starting at 0. Location
1M is the start of the second Mbyte of address space.
The memory map above shows the uses of the first Mbyte of
address space. The memory map is arranged in this way in
order to be compatible with the ISA standard.
The region from 0 to 640k-1 (00000h to 9FFFFh) is used by
DOS. The operating system is loaded at the bottom of this
area and it uses the remainder to load applications and data.
Motherboard video adapter memory is accessed between 640k
and 768k-1 (A0000h to BFFFFh). In your computer the
motherboard video BIOS is addressed between 768k and
800k-1 (C0000h to C7FFFh).
The region from 800k to 896k-1 (C8000h to DFFFFh) is
available for expansion card ROM, other than video BIOS. The
region from 896k to 960k-1 (E0000h to EFFFFh) is reserved.
While address space from 960k to 1M-1 (F0000h to FFFFFh)
is used by the motherboard BIOS.
When installing expansion cards the area of most interest is
between 768k and 896k-1 (C0000h to DFFFFh).
Configuring expansion ROM
Expansion card ROM is addressed in the C0000h to DFFFFh
region of processor address space.
Motherboard video BIOS is accessed from C0000h to C7FFFh.
If you are installing a video card it should be configured with
its BIOS occupying this region.
Note
If your video card does not allow you to configure the address range
of its BIOS it will be set to the C0000h range.
XEN OWNER'S HANDBOOK A/11