Technical data

SDA Description
9.1 Identifying the Bugcheck
First, invoke SDA to analyze the system dump file. The initialization message
indicates the type of bugcheck that occurred as follows:
Dump taken on 31-JAN-1993 16:34:31.23
INVEXCEPTN, Exception while above ASTDEL or on interrupt stack
SDA>
An exception occurred that caused the system to signal a bugcheck, and signal
and mechanism arrays have been created on the current operating stack.
9.2 Identifying the Exception
Use the SHOW STACK command to display the current operating stack. In this
case, it is the interrupt stack. The following example shows the interrupt stack
and the signal and mechanism arrays. See the SHOW STACK command for a
complete description of the format of the stack display.
CPU 01 Processor stack
----------------------
Current operating stack (INTERRUPT)
8006A378 8000844B ACP$WRITEBLK+0A0
.
.
.
SP => 8006A398 7FFDC340
8006A39C 8006A3A0
8006A3A0 80004E7D EXE$REFLECT+0D4
8006A3A4 04080009
8006A3A8 00000004
8006A3AC 7FFDC368
8006A3B0 FFFFFFFD
8006A3B4 8001774E
8006A3B8 0000074F
8006A3BC 00000001
8006A3C0 00000005
8006A3C4 0000000C
8006A3C8 00000000
8006A3CC 80069E00
8006A3D0 8005D003
8006A3D4 04080000
8006A3D8 80009604 EXE$FORKDSPTH+01C
.
.
.
The mechanism array begins at address 8006A3A8
16
and ends at address
8006A3B8
16
. Its first longword contains 00000004
16
. The signal array begins
at address 8006A3C0
16
and ends at 8006A3D4
16
. Its first longword contains
00000005
16
and its second longword contains 0000000C
16
. Examination of the
signal array shows the following:
• The exception code is 0C
16
, indicating an access violation.
• The reason mask is zero, indicating that the instruction caused a protection
violation (instead of a length violation) when it tried to read the location
(rather than write to it).
• The virtual address that the instruction attempted to reference was
80069E00
16
.
SDA–25