04-Dec-88
Randy Pratt [73047,2312]


                         KQ4 / LSL2 on the PCjr
                         ----------------------

The following are patches which allow the 512K versions of King's Quest IV
and Leisure Suit Larry II to work on a 640K PCjr.  While the speed will be
slower than other Sierra games, it will certainly be acceptable to most.

The basic approach to making the games functional is to modify two files on
Disk 1.  First, the Tandy graphics driver must be changed to work with the
PCjr.  Second, the SIERRA.EXE file must be changed to not automatically
stop when it encounters a PCjr.

The following is known to work on TANDY320.DRV files dated 09-15-88 at 4:29
pm.  The patch to SIERRA.EXE is smaller but, because of the different number
of versions around, is a little more complex to perform.  It should work on
any SIERRA.EXE file which tells you "Can't run on a PCjr!" when you invoke it.
Good luck, and if you have suggestions, improvements, or additional versions,
please upload them here.


First, place the following lines in a file called JR320.DBG (except for
the identifier lines with all the equal signs):

====================== JR320.DBG =====================
E 10A 6A 72 33 32 30 20 20 20
E 113 50 43 6A 72 20
E 118 77 69 74 68 20 52 47 42
E 120 20 6D 6F 6E 69 74 6F 72
E 128 20 2D 20 31 36 20 63 6F
E 130 6C 6F 72 73 20 20 20 20
E 138 20 20
E 449 E8 24 03
E 770 B4 05 B0 80 CD 10 8A DF
E 778 32 FF B8 00 04 F7 E3 C3

R CX
0680
W
Q
====================== end of JR320.DBG =====================



Then, place the following lines in a file called JR320.BAT (again, leave
out the lines with the equal signs):

======================== JR320.BAT ========================
if not exist jr320.dbg goto noSourceCode
copy tandy320.drv jr320.drv
debug jr320.drv <jr320.dbg
goto end
:noSourceCode
Echo You must have JR320.DBG on this disk
echo for this process to work properly.
:end
======================== end of JR320.BAT ========================



Then, put JR320.BAT, DEBUG.COM, TANDY320.DRV, and JR320.DBG on a separate
formatted disk (to be safe).  With this disk in your "current" drive, type
"JR320".  (Don't include the quotes.)  This should create a new file on your
disk named JR320.DRV.  Copy this "JR320.DRV" file onto your PLAY copy of
Disk 1 of KQ4 or LSL2.


Next, we must prevent SIERRA.EXE from checking for the PCjr ID byte, so do the
following:
   <Please do all of this on a COPY of your SIERRA.EXE file and keep a
    backup of your original disk 1 in a safe place with a write protect
    tab on it.  A good way to do this is to use the same disk you used
    for the above modifications.>

   copy  SIERRA.EXE SIERRA.XXX (it is important that the file not have a
                                file extender of EXE when using DEBUG)

   debug SIERRA.XXX
     (the following are DEBUG commands.  Do not type anything in parens)

   s 100 ff00 FE FF 80 FB FD 75 08 (this searches the file for those bytes)
   (count to where the FD is and display that offset - this requires counting
    in hexidecimal up from the first number displayed on the resulting line)

   d ??? ??? (the FD offset - ex. d 49A 49A - this should respond with a
              display of the single byte at that offset - if it's not FD
              then check your offset and retry the "d" command)

   e ???      (ex.  e 49A - prepares you to change the byte at that position)
   00 <enter> (this circumvents the ID check by replacing the FD with 00)
   w          (this writes your changes back to the disk)
   q          (this leaves DEBUG)

   copy SIERRA.XXX b:SIERRA.EXE (copy the file back to its original name
                                 on your PLAY copy of disk 1.  Do NOT
                                 overlay your original SIERRA.EXE file.)
                                              ========


Lastly, you should run the customization program on your play disk 1.  Follow
the instructions included with the game to do this.  You will find a new
option on one of the selection screens that will let you choose the PCjr
in 16 color mode.

Because programs run faster on the PCjr if they are run in memory above the
initial 128K on the system board, it is a good idea to create a small (64-128K)
ramdisk in low storage to "eat up" the rest of this low memory.  If you are
using the IBM memory sidecars and their accompanying software, you can use
the following lines in a CONFIG.SYS file on your DOS start-up disk to make
this all happen:

device=ramdisk.com 128
device=pcjrmem.com /e
files=20

(Be sure to use the FILES=20 line as this seems to get rid of a number of
problems with saving games and recognizing disk changes.)

Having done all of this, you're ready to go.  Remember to boot with the DOS
disk containing your new CONFIG.SYS file.

Regards,
Randy