Digital archaeology, game disassemblies and more

Blocken - Debug Functions and Graphics Viewer

What happens when you cross Breakout with puzzle game versus mode mechanics? You get the adorable hot mess that is Blocken! 

Debug Flags

The byte value at 0x304312 in RAM holds a number of debug flags for the game.

Bit 1 - Gameplay debug info

When this bit is set, debugging information appears at the top of the screen during gameplay.

Bit 2 - Skip introduction

This flag skips the opening animation that plays during the attract mode

Bit 3 - Skip mode select

This will skip the mode select that appears in game type B

Bit 4 - Skip difficulty select

This will skip the difficulty select menu.

Bit 5 - Skip story mode intros

This will skip all of the story mode stage introductions

Bit 6 - Action list

With this flag enabled, pressing P2 Button 1 + 2 will show an Action list, detailing each of the discrete code objects that are running. This is only available during gameplay.

While on this screen, P2 Up/Down will scroll through the list, and P1 Button 1 will return to the gameplay.

Actually, this action list is also referenced elsewhere in the code, in a piece of code that I believe is related to creating tasks, meaning it can be displayed in parts of the program that aren't gameplay (attract mode, etc). I haven't been able to figure out how to properly access it this way, if it even can be done with the final code, but here's a quick test cheat if you want to see it:

  <cheat desc="Action List test">
    <script state="run">
      <action>maincpu.pd@30380e=003086e6</action>
    </script>
  </cheat>

Bit 7 - Slow motion gameplay

When enabled, gameplay will run in slow motion.

And now, here are the cheats to access these exciting features! Included is a cheat to show the status of each bit in the debug byte.

  <cheat desc="Display gameplay debug text (bit 1)">
    <script state="on">
      <action>maincpu.pb@304312=(maincpu.pb@304312 ^ 02)</action>
    </script>
  </cheat>

  <cheat desc="Skip introduction animation (bit 2)">
    <script state="on">
      <action>maincpu.pb@304312=(maincpu.pb@304312 ^ 04)</action>
    </script>
  </cheat>

  <cheat desc="Skip mode select screen (bit 3)">
    <script state="on">
      <action>maincpu.pb@304312=(maincpu.pb@304312 ^ 08)</action>
    </script>
  </cheat>

  <cheat desc="Skip difficulty select screen (bit 4)">
    <script state="on">
      <action>maincpu.pb@304312=(maincpu.pb@304312 ^ 10)</action>
    </script>
  </cheat>

  <cheat desc="Skip story mode stage intro (bit 5)">
    <script state="on">
      <action>maincpu.pb@304312=(maincpu.pb@304312 ^ 20)</action>
    </script>
  </cheat>

  <cheat desc="Show action list (bit 6)">
    <comment>Press P2 Button 1 + 2 to show list during gameplay</comment>
    <script state="on">
      <action>maincpu.pb@304312=(maincpu.pb@304312 ^ 40)</action>
    </script>
  </cheat>

  <cheat desc="Slow motion gameplay (bit 7)">
    <script state="on">
      <action>maincpu.pb@304312=(maincpu.pb@304312 ^ 80)</action>
    </script>
  </cheat>

  <cheat desc="Display debug settings">
    <script state="run">
      <output format="Display gameplay debug text: %01d">
        <argument>(maincpu.pb@304312 BAND 02) RSHIFT 1</argument>
      </output>
      <output format="Skip introduction animation: %01d">
        <argument>(maincpu.pb@304312 BAND 04) RSHIFT 2</argument>
      </output>
      <output format="Skip mode select screen: %01d">
        <argument>(maincpu.pb@304312 BAND 08) RSHIFT 3</argument>
      </output>
      <output format="Skip difficulty select screen: %01d">
        <argument>(maincpu.pb@304312 BAND 10) RSHIFT 4</argument>
      </output>
      <output format="Skip story mode stage intro: %01d">
        <argument>(maincpu.pb@304312 BAND 20) RSHIFT 5</argument>
      </output>
      <output format="Show action list: %01d">
        <argument>(maincpu.pb@304312 BAND 40) RSHIFT 6</argument>
      </output>
      <output format="Slow motion gameplay: %01d">
        <argument>(maincpu.pb@304312 BAND 80) RSHIFT 71</argument>
      </output>
    </script>
  </cheat>

Cell Check

Holding P2 Button 1 on startup will bring up a very basic graphics viewer.

That's all we've got for Blocken! Enjoy slow motion mode, I guess.


  • 2019.10.30 23:10 by Ryou