Re: CMS abend caused by cmd "discard" at sixpack 1.2

I will fix this... my code.

By the way, I wrote the DISCARD command (and FILELIST, RDRLIST, PEEK, NOTE, SENDFILE, etc) for VM/SP 2 many years ago :-)

Bob

PS.  I am on the US east coast for the next 10 days, delivering my son to college, then taking a vacation with my wife.  So my participation in this list will be somewhat sporadic.

--- In [email protected], "Kevin Leonard" <hercules-list@...> wrote:
>
> > DMSITP143T SPECIFICATION EXCEPTION OCCURRED AT 0176D6 IN SYSTEM
> > ROUTINE  Î     ,
> > RE-IPL CMS.
> > CP ENTERED; DISABLED WAIT PSW '00020000 4001B436'
> 
> This looks to be a minor bug in DMSCPF HRC350DS, which adds
> support for commands of the form:
> 
>         FIFO | LIFO | DISCARD cpcommand
> 
> If you say "DISCARD " with a trailing blank, it works.  If
> you say "DISCARD" without the blank, you get the pic6.  The
> code doesn't correctly handle the possibility of one of
> FIFO|LIFO|DISCARD with nothing at all after the initial
> word.  For "DISCARD", it does:
> 
>          CLC   0(8,R2),DISCARD is it 'DISCARD'
>          BNE   NORMAL         nope
>          SR    R6,R6          remember DISCARD
>          LA    R2,8(R2)       skip past 'DISCARD '
>          S     R3,EIGHT       decrement CP command length
> 
> then tests the length of the remaining command text:
> 
>          LTR   R3,R3          anything left in the buffer?
>          BZ    WRAPUP         no
> 
> except that the length register, R3, contains X'7FFFFFFF'
> rather than zero, so the test doesn't catch the absence of
> any CP command to be issued and doesn't branch around the
> diagnose X'0008'.  CP fails the diagnose with a pic6
> because of the invalid length.
> 
> A couple of things.  One is that R3 already contains the
> flag bits to be passed to diagnose in the high-order bits,
> which might screw up the length arithmetic if the bits are
> anything but zero.  The other is that the "anything left in
> the buffer" test needs to ensure the remaining length is positive,
> not just non-zero, because if there isn't any data after the
> first token, subtracting the expected length of the token
> plus one will make the length go negative.
> 
> -- 
> Kevin
>