QIO Configuration and Management Manual

Configuring the QIO Subsystem
QIO Configuration and Management Manual—424717-008
2-13
Setting an Alternate Base Address
Valid starting addresses for the QIO shared memory segment are from 0x10000000 to
0x4c000000. The base addresses must be in 32 MB increments. The default starting
address is 0x20000000.
The last valid flat segment address for the QIO segment is 0x4e000000-1. But you
should decrease your segment size such that the last valid QIO segment address is
the default value of 0x4000000-1; see the subsection Setting the Size of QIO Memory
on page 2-14. By making the QIO segment stop at the default ending address, you
ensure that the new environment does not conflict with dynamically allocated flat
segments.
Altering the base address of the QIO segment changes only the starting point of the
QIO segment. Altering the base address does not change the size of the segment.
Thus, changing the base address can cause the QIO segment to encroach on flat
memory allocated to programs. You must thoroughly understand your memory
requirements before altering the base address of the QIO segment.
Figure 2-4. QIO Shared Memory Segment Beginning at a Higher Base Address
than the Default
2000.0000
(default)
0800.0000
QIO Shared Memory
Segment
(Size reduced by specified
starting address)
QIO IOperm 32 MB
(No change in size)
QIO segment starting
address increased from
default of 2000.0000
Main Stack and
Flat Segment Memory
Space Reserved for
Programs
Base Addresses
5000.0000
4200.0000
4000.0000
VST013.vsd
Process Heap and
Process Globals
4E00.0000
Unassigned Flat
Memory Space