From:	CRDGW2::CRDGW2::MRGATE::"SMTP::CRVAX.SRI.COM::RELAY-INFO-VAX"  7-JAN-1991 23:23:09.98
To:	MRGATE::"ARISIA::EVERHART"
CC:	
Subj:	INVEXCEPTN bugcheck caused by VMS 5.4-1 LATmaster

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Date:     Mon, 7 Jan 91 17:57 CDT
From: <RR%SWTEXAS.BITNET@ricevm1.rice.edu>
Subject:  INVEXCEPTN bugcheck caused by VMS 5.4-1 LATmaster
To: info-vax@sri.com
X-Original-To:  info-vax@sri.com

VMS 5.4-1 with LATmaster crashes with:

  INVEXCEPTN, Exception while above ASTDEL or on interrupt stack

LTDRIVER (image file id X6.0-212) caused the crash.
The instruction (at LTDRIVER+01ECC) BISW2 #02,78(R5)
causes the access violation because R5 gets zeroed
by a MOVC3 earlier in the code stream.

When the above was reported to Digital CSC the attached
patch was supplied.

R.R. Rodriguez
RR@SWTEXAS.BITNET

--------------------------------------------------------------------

Workaround received from CSC:
----------------------------
Extract and cut the following set of PATCH commands as a command
procedure, then execute it.  The procedure will modify the LATmaster
LTDRIVER image to workaround this problem.
---------------------------------------------------------------------
$ SET DEFAULT SYS$COMMON:[SYS$LDR]
$ PATCH LTDRIVER
SET ECO 2
REPLACE/INSTRUCTION 01ECC
'BISW2 #02,B^78(R5)'
EXIT
'MOVL B^14(R9),R5'
'BISW2 #02,B^78(R5)'
EXIT
UPDATE
EXIT
$ EXIT
---------------------------------------------------------------------
Example of Patch Application:

Extract the above twelve lines and placed them in a command procedure
called FIXLAT.COM.  Then, executed this command procedure as shown
below.  The indented lines are the echoed commands from your command
procedure:

$ SET PROCESS/PRIV=   ! whatever is necessary to modify LTDRIVER
$ SET VERIFY
$ @FIXLAT
        $ SET DEFAULT SYS$COMMON:[SYS$LDR]
        $ PATCH LTDRIVER

          PATCH  Version 4-00    15-Sep-1984

        Image does not contain local symbols
        Some or all global symbols not accessible
        PATCH> SET ECO 2
        PATCH> REPLACE/INSTRUCTION 01ECC
        OLD> 'BISW2 #02,B^78(R5)'
        OLD> EXIT
        NEW> 'MOVL B^14(R9),R5'
        NEW> 'BISW2 #02,B^78(R5)'
        NEW> EXIT
        old:    00001ECC:  BISW2   #02,B^78(R5)
        new:    00001ECC:  BRW     PAA
        new:    00001ECF:  NOP
        new:    PAA:  MOVL    B^14(R9),R5
        new:    00000204:  BISW2   #02,B^78(R5)
        new:    00000208:  BRW     00001ED0
        PATCH> UPDATE
        Updating image file SYS$COMMON:[SYS$LDR]LTDRIVER.EXE;2
        PATCH> EXIT
$ SET NOVERIFY

You should reboot your system or cluster for the changes to take effect.


SOLUTION:

Digital expects that this problem will be corrected in a future release
of the LATmaster software.
-----------------------------------------------------------------------

