anchor.diff:  CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 2290" "InstallLocation"
   IF NOT "%REG%" == "" (
   	REM # check if TNT.WAD can be found there
  -	IF EXIST "%REG%\base\TNT.WAD" SET "IWAD_PATH=%REG%\base\TNT.WAD" & GOTO :iwad_check
  +	IF EXIST "%REG%\base\TNT.WAD" SET "IWAD_PATH=%REG%\base\TNT.WAD" & GOTO :iwad_found
   )
   REM # is GOG : Final DOOM installed?
   CALL :reg "HKLM\SOFTWARE\GOG.com\Games\1435848742" "Path"
   IF NOT "%REG%" == "" (
   	REM # check if TNT.WAD can be found there
  -	IF EXIST "%REG%\TNT\TNT.WAD" SET "IWAD_PATH=%REG%\TNT\TNT.WAD" & GOTO :iwad_check
  +	IF EXIST "%REG%\TNT\TNT.WAD" SET "IWAD_PATH=%REG%\TNT\TNT.WAD" & GOTO :iwad_found
   )
   GOTO :iwad_check
   
  
positive.code: CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 2290" "InstallLocation"
  IF NOT "%REG%" == "" (
  	REM # check if PLUTONIA.WAD can be found there
  	IF EXIST "%REG%\base\PLUTONIA.WAD" SET "IWAD_PATH=%REG%\base\PLUTONIA.WAD" & GOTO :iwad_check
  )
  REM # is GOG : Final DOOM installed?
  CALL :reg "HKLM\SOFTWARE\GOG.com\Games\1435848742" "Path"
  IF NOT "%REG%" == "" (
  	REM # check if PLUTONIA.WAD can be found there
  	IF EXIST "%REG%\PLUTONIA\PLUTONIA.WAD" SET "IWAD_PATH=%REG%\PLUTONIA\PLUTONIA.WAD" & GOTO :iwad_check
  )
  
  :iwad_check
  REM # did we find the IWAD in GOG / Steam?
  REM # TODO: if IWAD was found in GOG / Steam, offer to copy it into PortaDOOM
  IF EXIST "%IWAD_PATH%" GOTO :iwad_found
  
  :iwad_missing
  REM --------------------------------------------------------------------------------------------------------------------
  
negative.code: CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 2280" "InstallLocation"
  IF NOT "%REG%" == "" (
  	REM # check if DOOM.WAD can be found there
  	IF EXIST "%REG%\base\DOOM.WAD" SET "IWAD_PATH=%REG%\base\DOOM.WAD" & GOTO :iwad_found
  )
  REM # is GOG : The Ultimate DOOM installed?
  CALL :reg "HKLM\SOFTWARE\GOG.com\Games\1435827232" "Path"
  IF NOT "%REG%" == "" (
  	REM # check if DOOM.WAD can be found there
  	IF EXIST "%REG%\DOOM.WAD" SET "IWAD_PATH=%REG%\DOOM.WAD" & GOTO :iwad_found
  )
  REM # is Steam : DOOM 3 BFG Edition installed?
  CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 208200" "InstallLocation"
  IF NOT "%REG%" == "" (
  	REM # check if DOOM.WAD can be found there
  	REM # TODO: this WAD is broken and censored and we should patch it automatically
  	IF EXIST "%REG%\base\wads\DOOM.WAD" SET "IWAD_PATH=%REG%\base\wads\DOOM.WAD" & GOTO :iwad_found
  )
  REM # is GOG : DOOM 3 BFG Edition installed?
  CALL :reg "HKLM\SOFTWARE\GOG.com\Games\1135892318" "Path"
  IF NOT "%REG%" == "" (
  	REM # check if DOOM.WAD can be found there
  	REM # TODO: this WAD is broken and censored and we should patch it automatically
  	IF EXIST "%REG%\base\wads\DOOM.WAD" SET "IWAD_PATH=%REG%\base\wads\DOOM.WAD" & GOTO :iwad_found
  )
  GOTO :iwad_check
  
  