Owner`s manual

The XMI supports 2 gigabytes of physical memory space and 512 megabytes
of I/O space, as shown in Figure 3–2.
Figure 3–2: XMI Memory and I/O Address Space
Byte Address
0000 0000
Physical Memory Space
(2 Gigabytes)
Unused Space
I/O Space
msb−p374−90
7FFF FFFF
0000
(512 Megabytes)
8000
0000
DFFF FFFF
E000
FFFF FFFF
Register addresses for a particular device in a system are found by adding
an offset to the base address for that particular device. To distinguish
between addresses in XMI address space and addresses in VAXBI address
space, we use the following convention:
lowercase bb + offset indicates an address in VAXBI address space
uppercase BB + offset indicates an address in XMI address space
3–2 VAX 6000 Model 500 Mini-Reference