[img] Extensions to the JSW48 Game Engine
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During 1984 and 1985 while I was writing my JSW Room editor, I also made a few changes to the JSW48 game engine to add features or to increase functionality. I originally rewrote the whole code, but then I changed tack and tried to ensure that the changes were as small as possible and could be patched on top of existing code. This meant that I could distribute my improvements without having to distribute the complete code.

In July 2006 there was a discussion on the Jet Set Willy list on using Intel Hex files for distributing patches. I have created hex patchfiles for each of my patches.

The patches are described here:
  • Removing the Attic bug
  • Removing Interface 1 pause crash
  • Releasing password code space
  • Increasing the number of rooms
  • Exiting from JSW without clearing memory
  • Since typing up my commented JSW assembly file I have added some more patches to the code. These are:
  • Room-specific Willy sprites
  • Wall blocks at head height
  • Fixing the block graphics bug
  • The full code is available here:
    JetSet.sna 48K
    Standard Snapshot
    JetSet.ssn 64K
    Speculator Snapshot
    JetSet.tap 32K
    Spectrum Tapefile
    JSW.tap 32K
    Tapefile with JSW split into
    CODE, Sprites, Objects, Rooms
    Other notes:
    7bitRooms   wr/R  Access/htm  wr/R  Attic/hex   wr/R  Exit/hex    wr/R  GameExit    wr/R  jsw48/asm   wr/R 
    jsw48/lst   wr/R  Make       wr/R  NoPass/hex  wr/R  Patch/htm   wr/R  Patches/htm wr/R  Pause/hex   wr/R 
    Pause/htm   wr/R  RoomNum/hex wr/R  Rooms/hex   wr/R  Rooms/htm   wr/R  Sprites     wr/R  Teleport    wr/R 
    WallL/hex   wr/R  WallR/hex   wr/R  WillySP/hex wr/R 

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    Last update: 20-Feb-2017