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PATCHES.md

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This instructions apply to 64-bit versions of Dwarf Fortress.

I use Hopper Disassembler, it's available for OS X and Linux and can open executables for all platforms. You can use trial version that's is limited to 30 minutes which is enough for our needs.

Note: usually addresses don't change much, and usually they increase. So if some address you found is completely different from the address in previous version, it's likely incorrect.

  1. Windows & macOS only Find a function that references string "Tileset not found". The address of this function is A_LOAD_MULTI_PDIM.

  2. Find a function that references string "Here we have". Rename it to render_map. Its address is A_RENDER_MAP.

  3. Find a function that references string "Following". Rename it to dwarfmode_render_main.

  4. Find a call of render_map from dwarfmode_render_main. The address of the call instruction is p_dwarfmode_render.

  5. Open a list of references to render_map. There will be a function referencing it four times. The addresses of the four call instructions are p_advmode_render.

5+. At each of the four addresses there are either call, call (Windows) or call, mov, call / call, lea, call (Linux and macOS) instructions. Make sure that the total length of these instructions matches values specified for each address in p_advmode_render.

  1. Go to any of the four call instructions from the last step. The address of a function called right after render_map is A_RENDER_UPDOWN (use function address, not a call instruction address).

  2. Look for 0x30000000 in disassembly in the second half of the code, closer to the end.

    You need to find the following code:

     compare with 0x7
 jump ADDR
 compare with 0x2
 jump ANOTHER_ADDR
 compare with 0x30000000
 jump THE_SAME_ADDR

    Go to the address after the comparison with 0x30000000. Look for the first call instruction after that point, address of the called function is p_render_lower_levels. On Windows it may be a jmp instruction instead.

  3. Windows & macOS only Find references to SDL_GetTicks, look for a function that calls SDL_GetTicks in its very beginning and then again after some time. Go to its end, and look for the following code:

     call  SDL_SemPost
 ...
 call  SDL_SemPost
 ...
 call  SOME_ADDRESS
 ...
 call  ANOTHER_ADDRESS    <---- You need this instruction
 ...
 call  [rax+...]
 ...
 call  SDL_SemWait
 ...
 add   ..., 0x1 or inc ...
 ...
 call  SDL_SemPost

    Address of that call instruction above is p_display.

    p_display is not required on Linux. This may cause problems though, so better would be to build a special version of libgraphics.so with a call to renderer->display() removed.