On Fri, 16 Jan 2009 14:59:19 +0000 Tom Quarendon <tom.quaren...@teamwpc.co.uk>
wrote:
:>I've got an issue trying to make use of a piece of assembler code that's
:>coded in a non-reentrant style. Specifically the code doesn't allocate a
:>save area dynamically, it just allocates space in the CSECT for it. I've
:>got a driver program in C that's trying to call the code and when it
:>does I get a segmentation violation at the point that it tries to write
:>to the save area. The assembler code is as follows:
:> USING FRED,15
:>FRED CSECT
:> B SAVE-*(15)
:> L 15,0(1)
:> B RETURN
:>SAVE DS 0H
:> STM 14,12,12(13)
:> BALR 11,0
:> LA 0,*-FRED
:> SLR 11,0
:> LA 2,SAVEAREA
:> ST 2,8(13)
:> ST 13,4(2)
:>* LR 13,2
:> B 4(15)
:>*
:>RETURN DS 0S
:>* L 13,SAVEAREA+4
:> L 14,12(13)
:> LM 0,12,20(13)
:> BR 14
:> LTORG
:>
:>SAVEAREA DS 18F
:> END
:>As it stands above, I can call the code fine. Uncomment the LR 13,2 and
:>the program crashes at that point.
:>Can anyone help my understand why this doesn't work (other that the fact
:>that the code is clearly loaded into read-only storage) and what I'd
:>need to do to make it work? Clearly this kind of style is allowable in
:>the right environment, I'm just struggling slightly to understand how I
:>set up that environment. I have complete freedom in all things, except
:>the above assembler code -- I can't change that. Otherwise I can do
:>anything, compile options, link/bind options, driver program etc etc. If
:>the only solution is changing the code above, I'd like to know that too,
:>and what's required, but that has to be the absolute last resort. All
:>other possibilities exhausted. Final option.
:>I hope I've been (relatively) clear in what I'm trying to do here.
:>Thanks in advance for any assistance.
If the only r/w area is the savearea, change the code to use the linkage
stack.
BAKR R14,0
* leave R13 as it is
at the end
PR ,
--
Binyamin Dissen <bdis...@dissensoftware.com>
http://www.dissensoftware.com
Director, Dissen Software, Bar & Grill - Israel
Should you use the mailblocks package and expect a response from me,
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