NonStop S-Series Server Description Manual (G06.24+)

Memory Addressing and Access
HP NonStop S-Series Server Description Manual—520331-003
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Main Stack and SRL Data
Main Stack and SRL Data
Following the space allocations for the user-allocatable flat segments are several
regions that provide relative addressing for the main stack of the process and instance
data for shared run-time libraries (SRLs). See Figure 4-7. The 4E region (hexadecimal
address 4E000000) is the beginning of this area, and the 5A region is the end of the
area (address of the last byte is 5BFFFFFF).
The main stack is allocated for all processes except privileged native processes.
(Native mode and processes, as well as TNS modes and processes, are described in
Section 5, Instruction Processing Environments). The reason for this exception is that
privileged native processes start in the privileged state and continue to execute in that
state for the rest of their existence. Thus they never need to use the main stack.
The main stack begins at the end of the 4E region and grows toward lower addresses.
The main stack is said to originate at relative address 50000000. (The first byte within
the stack area is thus 4FFFFFFF.)
If a process has private SRL procedures, instance data for these procedures is
allocated upward from the start of the 50 region. Instance data for public SRL
procedures, if any, is allocated downward from the end of the 5A region.
Other data for a process, such as the process file segment, privileged stack, and
debug stack, are located in the third region of Kseg2, discussed later in this section.