NonStop S-Series Server Description Manual (G06.27+)

Native Execution Mode
HP NonStop S-Series Server Description Manual—520331-004
7-11
Invoking Privilege Requires Taking an Exception
Figure 7-5. syscall Exception or Address Error Exception Sets Privileged State
Callable
Procedure
PEP Table in
Code Segment
Nonprivileged
Callable
Privileged
Set
Privilege
Instruction
Failure
Legal
Procedure
Label?
PCAL
or
XCAL
or
DPCL
PCAL
Instruction
Millicode
Millicode
syscall
Exception
Handler
Code
Segment
Yes
No
syscall
TNS Mode
Accelerated Mode
PCAL
Sequence
Code
Segment
Gateway
Sequence
SL Code
Attempt
Load Byte
Address
Legal?
Yes
No
(Already Privileged)
Kseg2
Native Mode
Calling
Jump
Sequence
Native
Program Code
In
Gateway
Code?
Trap
No
Yes
Enter_Priv
Routine
Gateway
Sequence
SLr Code
Attempt
Load Byte
Address
Legal?
Yes
No
(Already Privileged)
Kseg2
Enter_Priv
Routine
or
XCAL
In
Gateway
Code?
Trap
No
Yes
VST315.vsd