Interrupt Handler Flowchart - HP 3000 III Series Manual

In t err up t Sys te m
of the two vertically-aligned pins.
The interrupt poll line carries the INTPOLL signal from the lOP
to connector PI of the device interface peA with the next highest
priority. It enters this PCA on the fifth vertically-aligned pair
of connector pins from the left; pins 48 (INTPOLL IN) and 47
(GND). The signal is exited from each PCA on the seventh ver-
tically-aligned pair of connector pins from the left; pins 44
(IN'rpOLL OUT) and 43 (GND).
ROM EXTERNAL DEVICE INTERRUPT PROCESSING
YES
--INT5
SECOND OR
GREATER LEVEL
EXTERNAL
INTERRUPT
DISPATCHER BEING
INTERRUPTED OR SECOND
OR GREATER LEVEL EXTERNAL
INTERRUPT
DISPATCHER
BEING INTERRUPTED
- - INT6
0+ 3: = DEVICE
NUMBER.
SAVE CONTENTS
OF CIR IN X.
ZERO ABS-Bank
REG.
CLEAR H/W
DISPATCHER FLAG.
SET 0.(0:11
[ 0.(0:1):=11
FOR IXIT USE.
FETCH INT DEVICE
NUMBER.
CALCULATE DRT ADDR.
DB:=DBI FROM DRT.
STATUSREG:=
%140000.
FETCH PLBL.
DB-BAN K: =00
RESET EXT INT BIT
CPX1.l8:11.
START
FETCH CPX 2
REGISTER
HARDWARE EXTERNAL INTERRUPTS
MAP TO ROM ADDRESS 3 WHICH
JUMPS TO THE INTERRUPT MICROCODE
r------I~--....,
- - -
IR
,.....-_....._--""1---
INT1
QUEUE DOWN H/W
TOS REGISTERS.
LAY STACK MARKER
ON CURRENT STACK.
PUSH DB-BANK & DB
ON STACK.
ZERO STACK BANK
REGISTER.
'---.....;.....;;.,.---... ---INT2
EXECUTING ON
i-US;.;:E;;.;R..;;,S.;.;TA.;.;C;;.;K .... _ - - INT 3
SET ICS 01 INTO
THE 0 REGISTER.
SET ICS FLAG.
SET ICS ZI INTO
THE Z REGISTER.
SET DL TO -1.
CALCULATE USER
RELATIVE S FROM
USER DB. SAVE AT
Ol~.
(01-6)= $-(01-41
A
Figure 8-7. Interrupt Handler Flowchart (Sheet
I
of 2)
8-25