AT&T 3B2 Off-Line Diagnostic Manual page 136

Version 3 Hardware System Board Diagnostics - - - - - - - - - - - - - - - - - - - - - -
Test Number: ' 7
Function: This test checks the segment offset fault.
Procedure: The descriptor tables are set up for the contiguous segments. The segment
offset of an entry is set to zero. The caches are flushed. The virtual address
corresponding to this entry is referenced.
Hardware Tested: The MMU chip is tested.
Data Returned: The MMU Fault Code register value and MMU Fault Address register value are
returned.
Notes: This test is run twice on systems with two MMUs; for example, the
382/1000 computer.
Test Numbers: 8 through 31
Function: These tests check the access fault.
Procedure: The descriptor tables are set up for contiguous segments. The appropriate
access occurs when allowed, and a fault occurs when disallowed. The caches
are flushed. The virtual address corresponding to this entry is referenced.
Hardware Tested: The MMU chip is tested.
Data Returned: The MMU Fault Code register value and the MMU Fault Address register value
are returned.
Notes: Tests 8 through 19 execute at user level while Tests 20 through 31 execute at
kernel level. This test is run twice on systems with two MMUs; for example,
the 382/1000 computer.
Test Access Test Access
No.
Allowed Operation No. Allowed
Operation
8
RWE R
20
RWE
R
9 RWE W 21 RWE W
10 RWE E 22 RWE E
11
RE R 23 RE
R
12
RE E 24 RE
E
13
E E 25 E
E
14
RE W 26 RE
W
15
EO R
27
EO
R
16 EO
W
28 EO W
17 Nonaccessible
R 29
Nonaccessible R
18
Nonaccessible
W
30
Nonaccessible
W
19
N onaccessible
E
31
Nonaccessible
E
3-96 OFF-LINE DIAGNOSTIC MANUAL