Word Perfect Patch
from CodeHead Technologies
Wednesday, May 6, 1992
--------------------------

The program and data files in this archive will enable you to patch your
copy of Word Perfect (either the August 18, 1989 version or the April 18,
1991 version) to remove a Word Perfect bug that causes MultiDesk Deluxe to
crash when Warp 9 is installed. 

To get technical about this, what's happening is that Word Perfect is using
the Line A SHOW MOUSE call [$A009] in a certain routine.  You can pass a
parameter to this call, telling Line A to show the mouse unconditionally no
matter how many times it has been hidden.  This is done by clearing the first
word in the Line A INTIN array.  But Word Perfect is incorrectly handling the
pointer to INTIN and is clearing the upper word of the _pointer_ itself --
leading to a garbage address, which causes a crash.

The offending code looks like this:

  dc.w    $A000
  clr.w   8(a0)
  dc.w    $A009

when it should be:

  dc.w    $A000
  move.l  8(a0),a0
  clr.w   (a0)
  dc.w    $A009

and unfortunately, this bug is repeated many times in the Word Perfect code.

Normally, the INTIN pointer in the Line A variable structure is pointing at
an address like $9000 -- which means that Word Perfect can incorrectly clear
the upper word and get away with it, because it's already zero to start with. 
But when Warp 9 and MultiDesk are installed, INTIN may be at a higher address;
high enough so the upper word is no longer zero.  If the upper word then gets
cleared ... bombs away on the next Line A call.

Therefore, we've prepared the patch files in this archive, which will
remove the offending instruction ("clr.w 8(a0)" -- it isn't doing anything
useful anyway) from your Word Perfect program file.

To perform the patch, follow these simple instructions:

  1.  IMPORTANT!!!  Make a copy of your Word Perfect program file and
      store it in a safe place, just in case something goes wrong during
      the upgrade process.  Don't modify your only copy!

  2.  Determine which version of Word Perfect you have, by running the
      program and choosing "About Word Perfect" from the Desk menu.  All
      versions of Word Perfect have the same number (4.1); it's the date
      we're concerned with.  These patches will only work with the August
      18, 1989 version or the April 18, 1991 version.  When you've
      determined your version, quit Word Perfect.

  3.  Run the program SUPERZAP.PRG, which is included with this archive
      file.  When the program starts, click the button labeled "Read ZAP
      Data."  A GEM file selector will appear. 

  4.  Use the file selector to locate and select the file which has the
      name corresponding to your version of Word Perfect; notice that the
      date is contained (in MM/DD/YY format) in the filename.  SUPERZAP
      will load the ZAP file, and the button underneath "Read ZAP Data"
      will now read "Patch WP 4/18/91" (or "8/18/89"), and become
      selectable.

  5.  Click on this button and a GEM file selector appears, letting you
      locate the copy of Word Perfect (usually named WP.PRG) that is to be
      upgraded.  Select the Word Perfect program file and SUPERZAP will do
      its job, removing the bug and preventing Word Perfect from
      interfering with the proper operation of MultiDesk Deluxe and Warp 9. 

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SUPERZAP is supplied with permission from the author Bill Aycock.
Thanks, Bill!