dMZX Forums: #98485 Freezes on level transition -> Archived MegaZeux Bugs -> Tracker

DoZ Q1 2011 entry #98485 (Thanatos Insignia) freezes in the latest GIT, both debytecode and normal MZX. Reach the level boundary at the end of the first level, and the game freezes (save for music) and MZX takes up a full processor core. Freeze appears between 410b0cd and cd95c1e.

The hang-up is caused by this segment of code in the Finish robot.

: "finish"
send "all" to "finish"

Can somebody answer me once and for all: Is "all" supposed to be self-inclusive? x(

And I will explain for the tenth freaking time: YES, it is. It was self-inclusive throughout the entirety of MZX's DOS reign, and was only self-exclusive during the port as a bug, during which I wrote the help file entry describing its then-present action. This was eventually corrected, but I forgot to change the help file to match.

ok

Taking a look into this since it's what's holding up the release. Robot.c is scary

As a matter of fact, Old-Sckool was right on the mark. Lancer's code broke in that revision due to a change in label caching combined with him forgetting to LOCK SELF. I believe in that same revision code was added to make sure GOTO/SEND ALL actually did something. While I don't have the code in front of me now, from what I recall it'd just keep going since the pointer that is cached is the command after the label. I'm going to try building the two sources and test this hypothesis out, but a compatibility fix would hopefully be as easy as caching next(+1?) instead of i from versions 2.80 to 2.83... I don't know the extent of changes after the fact that rely on this new behavior, though. Alternatively, Lancer could fix his obviously broken code

Proposed fix:

src/run_robot.c line 2052

...
        send_robot(mzx_world, robot_name_buffer, label_buffer, 0);

        // Compatibility fix for self-inclusive send commands directly preceeded by the target label
        if (mzx_world->version <= 0x0253 &&
            cur_robot->cur_prog_line + 2 + cur_robot->program_bytecode[cur_robot->cur_prog_line] == old_pos)
            cur_robot->cur_prog_line = old_pos;

        // Did the position get changed? (send to self)
...

What would be more likely is putting that in a function and calling it for every send command... this only deals with SEND "robot" "label"

I think you're on the right track; it makes a lot of sense that the compatibility fix we put in would break in this case, and you're also right that it's sloppy code causing the "freeze".

However, I'm not sure adding workaround code to another place is better than just turning off the original compatibility fix (re: label caching) if the world is 2.80 <= version < 2.84.

--ajs.

I had considered that, but I ultimately didn't try it because (if I remember correctly) the label caching code had no access to the current MZX world version... probably not a huge deal to change, really, though I haven't investigated it too deep.

What's the plan for this? I like the idea of turning off the original fix for 2.80 <= ver < 2.84.

Updating version to: None

Here's a dependency tree of the line numbers where every function is called that needs *mzx_world passed through it so this fix can be made in the label-caching code (counting the load robot functions too because I like consistency and those just have a "version" int) unless there is an easier way of getting the world version there for every case. + means that this function currently has access to *mzx_world

cache_robot_labels()

+src/counter.c:2564 
+src/counter.c:2601 in int set_counter_special(struct world *mzx_world, etc)
src/robot.c:277
src/robot.c:349 in void load_robot(struct robot *cur_robot, FILE *fp, int savegame, int version)
src/robot.c:3145 in void prepare_robot_labels(struct robot *cur_robot)

• void load_robot(struct robot *cur_robot, FILE *fp, int savegame, int version)
  

  src/robot.c:173 in struct robot *load_robot_allocate(FILE *fp, int savegame, int version)
  +src/world.c:1492 in static void load_world(struct world *mzx_world ...)
  

  
  
  
  • struct robot *load_robot_allocate(FILE *fp, int savegame, int version)
    

    src/board.c:291 in __editor_maybe_static void load_board_direct(struct board *cur_board, FILE *fp, int savegame, int version)
    +src/mzm.c:447
    +src/mzm.c:464 in int load_mzm(struct world *mzx_world ...)
    

    
    
    
    • __editor_maybe_static void load_board_direct(struct board *cur_board, FILE *fp, int savegame, int version)
      

      src/board.c:386 in struct board *load_board_allocate(FILE *fp, int savegame, int version)
      

      
      
      
      • struct board *load_board_allocate(FILE *fp, int savegame, int version
        

        +src/world.c:1485 in static void load_world(struct world *mzx_world ...)
        

  
  
  
• void prepare_robot_labels(struct robot *cur_robot)
  

  +src/counter.c:2465
  +src/counter.c:2515 in int set_counter_special(struct world *mzx_world, etc)
  src/robot.c:251 in void load_robot(struct robot *cur_robot, FILE *fp, int savegame, int version)
  src/robot.c:447 in void save_robot(struct robot *cur_robot, FILE *fp, int savegame)
  src/robot.c:1270 in static int send_robot_direct(struct robot *cur_robot, const char *mesg)
  src/robot.c:2821 in static void duplicate_robot_direct(struct robot *cur_robot, struct_robot *copy_robot, int x, int y)
  +src/run_robot.c:921
  +src/run_robot.c:1285 in void run_robot(struct world *mzx_world, etc)
  

  
  
  
  • void save_robot(struct robot *cur_robot, FILE *fp, int savegame)
    

    src/board.c:552 in int save_board(struct board *cur_board, FILE *fp, int savegame)
    +src/mzm.c:156 in void save_mzm(struct world *mzx_world ...)
    +src/world.c:719 in int save_world(struct world *mzx_world ...)
    

    
    
    
    • int save_board(struct board *cur_board, FILE *fp, int savegame)
      

      +src/world.c:707 in int save_world(struct world *mzx_world ...)
      

    
    
    
  • static int send_robot_direct(struct robot *cur_robot, const char *mesg)
    

    +src/robot.c:1383
    +src/robot.c:1391 in void send_robot(struct world *mzx_world ...)
    +src/robot.c:1405 in int send_robot_id(struct world *mzx_world ...)
    +src/robot.c:1411 in int send_robot_self(struct world *mzx_world ...)
    +src/robot.c:1421
    +src/robot.c:1426 in void send_robot_all(struct world *mzx_world ...)
    

    
    
    
  • static void duplicate_robot_direct(struct robot *cur_robot, struct_robot *copy_robot, int x, int y)
    

    src/robot.c:2884 in int duplicate_robot(struct board *src_board, struct robot *cur_robot)
    src/robot.c:2907 in void replace_robot(struct board *src_board, struct robot *src_robot, int dest_id)
    

    
    
    
    • int duplicate_robot(struct board *src_board, struct robot *cur_robot)
      

      +src/run_robot.c:501 in static void copy_xy_to_xy(struct world *mzx_world ...)
      +src/run_robot.c:559 in static void copy_board_to_board_buffer(struct world *mzx_world ...)
      +src/run_robot.c:2918
      +src/run_robot.c:2955
      +src/run_robot.c:4282
      +src/run_robot.c:4330 in void run_robot(struct world *mzx_world ...)
      

      
      
      
    • void replace_robot(struct board *src_board, struct robot *src_robot, int dest_id)
      

      +src/run_robot.c:2826
      +src/run_robot.c:2838
      +src/run_robot.c:2861
      +src/run_robot.c:2888 in void run_robot(struct world *mzx_world ...)
      

Updating version to: GIT


That's getting REALLY annoying.

Updating status to: Proposed Fix

Fixed in GIT dd7798ac39. I added a copy of mzx_world->version to struct robot through load_robot() so I could add a compatibility fix to the label caching function. Please verify this fix.

Updating status to: Fixed

Moving to: Archived MegaZeux Bugs