ARCHITECTURE AND INSTRUCTIONS
The interrupt pointer (or interrupt vector)
table (Fig.
2-9)
is
the link between
an
inter-
rupt type code and the procedure designated
to service interrupts associated with that
code. The interrupt pointer table occupies up
to
lK
bytes
oflow
memory. There may be up
AVAILABLE
INTERRUPT
POINTERS
(224)
RESERVED
INTERRUPT
POINTERS
(27)
DEDICATED
INTERRUPT
POINTERS
3FFH
3FCH
OB4H
OBOH
07FH
014H
010H
OOCH
(5)
OOBH
004H
OOOH
f--
TYPE
255
POINTER:
_
(AVAILABLE)
r--
TYPE
33
POINTER:
(AVAILABLE)
--'-
-
TYPE
32
POINTER:
-
(AVAILABLE)
-
TYPE
31
POINTER:
(RESERVED)
-
f--
TYPE
5
POINTER:
-
(RESERVED)
f--
TYPE
4
POINTER:
-
OVERFLOW
TYPE
3
POINTER:
~-BYTE
INT
INSTRUCTION
f--
TYPE
2
POINTER:
NON-MASKABLE -
r---
TYPE
1
POINTER:
SINGLE-STEP -
f--
TYPE
0
POINTER:
-
DIVIDE
ERROR
CS
BASE
ADDRESS
r---------
IP
OFFSET
"",,1.1-·
---16
BITs----I.~1
Figure 2-9. Interrupt Vector Table in Memory
2-9