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Subj:	Re: SMGSHR Patch for ANU-NEWS dropping into newsgroups while scrolling

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Date: 28 Feb 91 06:26:17 GMT
From: infopiz!mark@decwrl.dec.com
Subject: Re: SMGSHR Patch for ANU-NEWS dropping into newsgroups while scrolling
Message-Id: <6682.27cc3209@infocomm.com>
References: <1991Feb19.123812.1@rogue.llnl.gov>, <6667.27cb0840@inf, <1991feb27.144914.1@rogue.llnl.gov>
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Organization: INFO COMM - Computer Consulting, Redwood City, Ca
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In article <1991Feb27.144914.1@rogue.llnl.gov>, oberman@rogue.llnl.gov writes:
> In article <6667.27cb0840@infocomm.com>, mark@infocomm.com writes:
>> 
>> 	$ SET DEFAULT SYS$COMMON:[SYSLIB]
>> 	$ PATCH SMGSHR.EXE
>> 	REPLACE/INSTR 244F
>> 	'CLRL B^0FC(FP)'
> 
> Hmmm. I took a look at SMGSHR and I thing there is a typo here. The CLRL
> instruction is at 24FF, not 244F in V5.4-1.
> 

Hmmm . . . Yes, I blew it in the transcription. :-(

However, Bill Glass responded by E-mail to my posting of a patch with some 
more details of the problem he uncovered:

> Since you seem to have an interest in the problem, I'll pass on a copy of
> the mail I sent to Kevin so that he could provide details to DEC.  I actually
> "fibbed" a little in my original description of the bug.  The cause of the
> problem is more one of a duplicate declaration (a variable in an inner block
> hides a variable of the same name in an outer block).   This makes it virtually
> impossible to provide a patch.  You can however provide a work around (like
> your scheme) that will make READ_COMPOSED_LINE work correctly for normal
> input, but it may still fail when people do things like typing Control-C or
> Control-Z.

Bill,
	I was happy with what I did last night, but since you once again
challenged me the following patch really fixes the problem you pointed out
for all cases on my VMS V5.4-1 environment:

	! NOTE: First undo yesterday's patch, but that only is necessary for 
	!	performance reasons.

	$ SET DEF SYS$COMMON:[SYSLIB]
	$ PATCH SMGSHR.EXE
	REPLACE/INST 2ABC
	'MOVL    B^0FC(FP),R0'
	EXIT
	'MOVL       R0,B^20(SP)'
	'MOVL    B^0FC(FP),R0'
	EXIT
	UPDATE
	EXIT
	$ MCR INSTALL
	SYS$SHARE:SMGSHR/REPLACE
	
Since I don't have sources for V5.3 right handy, I'd recommend sticking to my
minor work around for the V5.3 systems since it actually works MUCH better than
the original code for ALL cases, and simply doesn't cover a few real cases that
weren't covered before anyway!

--- 
Mark Pizzolato - INFO COMM Computer Consulting, Redwood City, Ca
PHONE:	(415)369-9366	UUCP:  decwrl!infopiz!mark or uunet!lupine!infopiz!mark
DOMAIN:	mark@infocomm.com

