HP 3000 III Series Manual page 309

Inte r rup t Sys tern
Table
8-1. Interrupt Types (Continued)
ICS
ICS
41
42
43
44
40
120401
121001
121401
122001
120001
1---·-----·-l-,-~--I---'-----------·
. .
~ -
. . - -·-·----I-------·-------1-------
IExt Prog.1 STT
I I
I Executing
I
Label I No.
I
I nte r r upt Type
I
Par arne te r*
I
Stack**
I
(%)
I
(%)
I I I
I I I . I I
----~---
---'-'.
-------------------~-----I~--
. .
- ----I--------
115001 32
(Unused)
I I
115401 33
(Unused)
I I
116001 34
(Unused)
I I
116401 35
(Unused)
I
I
117001 36
(Unused)
I 1
11740137
Abse nt Code Segment
I
a. On PCAL P-Label
I
b. On EXIT N
I
c. On IXIT 0
I
Trace
I
a. On PCAL P-Label
I
b. On EXIT N
1
c. On IXIT 0
I
STT Entry Uncallable P-Label
I
Ab sent
Da
ta Se gment DST No.
1
Power
~
I
Cold Load
1
a. System I/O (SIO) 0
1
b. Direct I/O (DIG) Label
1
I
1
1--------- ------
~-------~-~------.-----
-----------
------~-
I
*Unless noted, the parameter is the External Program Label.
I
**Unless noted, Interrupts are serviced on the User Stack.
1
I
All User Traps (STT No. %31) are enabled
by the User Traps
I
bit in the Status Register.
1
8-3. INTERRUPT CONTROL STACK
The Interrupt Control Stack (ICS) is a single stack, unique to
the CPU, which is used in common by all external interrupts and
some of the internal interrupts (ICS type). When only minimal
data is to be handled by an interrupt routine, the data is pro-
cessed on the ICS. Otherwise, the separate data area defined in
the DRT must be used for data. The use of a common stack also
permits efficient nesting of interrupt routines by using stack
mar kers. The ICS has a permanent stack marker, set up by the
operating system which is used to enter the Dispatcher. Figure
8-1 illustrates the format of the Dispatcher marker on the ICS.
8-3