anchor.diff:      cr ." !screenshot"
       GD.REG_HSIZE GD.@ send32 GD.REG_VSIZE GD.@ send32
       GD.REG_VSIZE GD.@ 0 do
  -        i REG_SCREENSHOT_Y GD.c!
  +        i REG_SCREENSHOT_Y GD.!
           1 REG_SCREENSHOT_START GD.c!
           begin
               REG_SCREENSHOT_BUSY dup GD.@
  
positive.code: 
  PUBLICWORDS     \ }{
  
  : GD.Screenshot
      GD.finish
      1 REG_SCREENSHOT_EN GD.c!
      GD.REG_PCLK GD.@
  
negative.code:     over + swap
  ;
  
  : file>GD ( caddr u -- ) \ feed a file to the FT800 command buffer
      r/o open-file throw >r
      begin
          pad 512 r@ read-file throw
          ?dup
      while
          pad swap GD.supply
      repeat
      r> close-file throw
  ;
  