The New Adventures of World -1 and Friends
May 12th 2008 06:06
It's only fitting that, if I were to name the blog after this legendary glitch, that the first analysis shall focus on it. So, without further ado...
An Opening Note
Some of you, maybe even a lot of you, have heard of the minus world. The trick where you can manage to enter a vast never-ending ocean if you do the right thing, at the right time. But most of the time, it just stops at the point of telling you how to get there. Not so. With the support of the internet, I shall give you more. You will have your cake. You will eat it, too. I'll even provide a dessert menu for you. I will tell you how the minus world trick works, why it works, why the minus world even exists, and what else you can do with this strange detail in Super Mario Brothers' code.
Roadmap to the Level that Should Not Be
There are two roads the the Minus World, and if we were to compare them to real roads? One would be an unpaved road in Alaska in the depths of winter - That way is the actual trick at the end of world 1-2. The other is more like a massive highway akin to the US Interstate system, or perhaps the Autobahn - That road is the Game Genie, quick and easy.
The first way in, the trick is.... Tricky. First. You must reach the pipe leading up to the surface. Then stand on it. See the blocks above your head? Hit the second and third from the pipe, but not the one right next to it. What you need to do now is jump into the gap, and while still facing left, edge right into that block you left behind. Yes. Into. If you can pull this off, you'll end up moving INTO the block. From here, you need to keep jumping in that way, worming your way through the green pipe, and into the wall to the right of it. From there, you can actually walk to the right, and through the wall. You have to be careful to not go past pipe #2, else the warp room will load properly and you'll be left with the normal warp zone. Anyway. Pipe #1 on the far left will give you the Minus World, in all its infinite glory.
If you want the fast track, just key in YSAOPE YEAOZA LXAPYA on your game genie. Start playing. Good to go!
The Warp Zone Has MPD
Now that you know how to get to the minus world? It's time we learned why it is that this happens, and what it is. Now, a rather nifty fellow named doppelganger found this data out, and this shall be considered my cited source.
Really Long Link
However! This article is rather... arcane, even though doppel tries his best to demystify it. So it's summarization time.
First of all, the Minus World is... not actually level -1. It is level 36-1! However, in the graphics tables of SMB, attempting to lookup the tile for 36 doesn't produce a number (since, you will note, there is no world 10, nor is there any other world greater than 8. Thus two-digit values don't need to return a number anymore.). It produces? A blank tile. Thus, the hyphen is no longer tying two letters together, so instead you're going to level [blank]-1.
So why is it loading 36? That requires looking deeper into the code of level 1-2. It turns out that, in the normal circumstance, the warpzone in 1-2 loads the values for the warpzone, which are, in the data, exactly the same as the world numbers themselves. But when you get the minus world result, it instead loads the values 36-5-36, for the left, center, and right pipes respectively. What is that? It turns out that that's the code for the later, second warpzone in level 4-2. When you actually go there, you'll note that there's only one pipe, in the center, which leads to level 5. The other spaces are blank - just like how tile #36 just happens to be a blank tile!
This doesn't explain why it's loading it yet, so let's look a little closer. Now, the way level 1-2 is set up, when you first arrive near the exit, the game calls for a "normal scroll lock" in the terrain data. Then, there's a call for an "area change" in the enemy data, and a "sideways pipe" object in the terrain data. This means, very simply, that the pipe you walk into to get to the flag... takes you to the flag - all warps are coded in the enemy data - and the scroll lock means you can't go past the pipe. After this, the game calls the warp zone object in the enemy data, which checks to see if you're at the highest part of the map, and if so, breaks the scroll lock (since normally, you run across the top of the screen to get to the warp zone - hence, being on top would allow you to proceed there.). Then it adds to the warp zone counter (normally 0 for no warpzone) which turns on the 3 pipes, and kills the process.
Now, were you to go in the normal way, you'd also run into the warp zone scroll lock, which follows special rules. It basically uses some tricks to figure out the right warp zone - if you're in world 1 (which you are), it calls #4, which loads the normal first warp zone. If you're in a world later than world 1, but are in anything that is not a cloud level, it loads the second warp zone at the value 5 (the one that causes the minus world glitch if loaded in the wrong place), and finally if you're in a cloud level it calls 6, the final warp zone.
Forget that. That's what happens in a world in harmony. You're not in that world, here be dragons.
Things get strange now. If you were above the screen, you would encounter this scroll lock before you can access the pipes, which would fix the warps. But if you walk through the wall? You hit the warpzone object but not the scroll lock. This means the counter is at 1 now! Well, what happens is that the game normally takes those numbers 4, 5 and 6, and subtracts 4 to figure out what the correct warpzone counter is (since those 4/5/6 numbers code for the text, and the SMB programmers decided to make the actual warps depend on what the text was). But... 5-4 = 1. And you're already at 1, since that first object added 1 without asking the scroll lock if it's right, and the game blithely accepts whatever's in the variable. This is also why heading all the way to the right shuts the door to the minus world - because the scroll lock is at the end, where the hole you'd drop into the zone from is. So, all said and done, it reads code 5 instead of code 4, and loads the second warp zone - and the pipe on the left has the junk value of 36 (because in the real second warpzone, there is no left pipe), which takes you to level 36.
That was a monster of a description. So why, after all of this, is the minus world an infinite ocean? Doppelganger doesn't quite explain why it's an ocean level, so let's fill in the gaps. The area change from earlier (remember? The sideways pipe?) is the culprit. It's asking us to go to area 1, which is normally where the flag for 1-2 would be, were we still in 1-2. But... since the warpzone hit, we're not being sent to a world that obeys that rule. Instead, we're going to level 36 which... for reasons I'm not sure of, obeys the rules of worlds 2, 3 (though world 3 doesn't have a level that uses these rules, so it's ignored) and 7, which says that you're in a water world, and tells the game about the flag area after the water segment. However! Area changes, checking the world number as they do, can't really even understand what to do with world 36 - so it ends up not loading the end of the level, and just continues forever, since it isn't updating the area change data.
Bonus: The Crazy Levels
It turns out that This same kind of world mismatch can be exploited to lead to yet more worlds. Go back to that Game Genie code. That code alters the game to start you on 36-1... However, you can modify the third part of the code to lead to other values than 36. STart with AOAPYA as the third code bit, and start flipping the first letter, then maybe once you're done with that, the second. Between those two, you'll hit all sorts of other odd level values. From there? You shall gloriously explore!
Happy hunting~
An Opening Note
Some of you, maybe even a lot of you, have heard of the minus world. The trick where you can manage to enter a vast never-ending ocean if you do the right thing, at the right time. But most of the time, it just stops at the point of telling you how to get there. Not so. With the support of the internet, I shall give you more. You will have your cake. You will eat it, too. I'll even provide a dessert menu for you. I will tell you how the minus world trick works, why it works, why the minus world even exists, and what else you can do with this strange detail in Super Mario Brothers' code.
Roadmap to the Level that Should Not Be
There are two roads the the Minus World, and if we were to compare them to real roads? One would be an unpaved road in Alaska in the depths of winter - That way is the actual trick at the end of world 1-2. The other is more like a massive highway akin to the US Interstate system, or perhaps the Autobahn - That road is the Game Genie, quick and easy.
The first way in, the trick is.... Tricky. First. You must reach the pipe leading up to the surface. Then stand on it. See the blocks above your head? Hit the second and third from the pipe, but not the one right next to it. What you need to do now is jump into the gap, and while still facing left, edge right into that block you left behind. Yes. Into. If you can pull this off, you'll end up moving INTO the block. From here, you need to keep jumping in that way, worming your way through the green pipe, and into the wall to the right of it. From there, you can actually walk to the right, and through the wall. You have to be careful to not go past pipe #2, else the warp room will load properly and you'll be left with the normal warp zone. Anyway. Pipe #1 on the far left will give you the Minus World, in all its infinite glory.
If you want the fast track, just key in YSAOPE YEAOZA LXAPYA on your game genie. Start playing. Good to go!
The Warp Zone Has MPD
Now that you know how to get to the minus world? It's time we learned why it is that this happens, and what it is. Now, a rather nifty fellow named doppelganger found this data out, and this shall be considered my cited source.
Really Long Link
However! This article is rather... arcane, even though doppel tries his best to demystify it. So it's summarization time.
First of all, the Minus World is... not actually level -1. It is level 36-1! However, in the graphics tables of SMB, attempting to lookup the tile for 36 doesn't produce a number (since, you will note, there is no world 10, nor is there any other world greater than 8. Thus two-digit values don't need to return a number anymore.). It produces? A blank tile. Thus, the hyphen is no longer tying two letters together, so instead you're going to level [blank]-1.
So why is it loading 36? That requires looking deeper into the code of level 1-2. It turns out that, in the normal circumstance, the warpzone in 1-2 loads the values for the warpzone, which are, in the data, exactly the same as the world numbers themselves. But when you get the minus world result, it instead loads the values 36-5-36, for the left, center, and right pipes respectively. What is that? It turns out that that's the code for the later, second warpzone in level 4-2. When you actually go there, you'll note that there's only one pipe, in the center, which leads to level 5. The other spaces are blank - just like how tile #36 just happens to be a blank tile!
This doesn't explain why it's loading it yet, so let's look a little closer. Now, the way level 1-2 is set up, when you first arrive near the exit, the game calls for a "normal scroll lock" in the terrain data. Then, there's a call for an "area change" in the enemy data, and a "sideways pipe" object in the terrain data. This means, very simply, that the pipe you walk into to get to the flag... takes you to the flag - all warps are coded in the enemy data - and the scroll lock means you can't go past the pipe. After this, the game calls the warp zone object in the enemy data, which checks to see if you're at the highest part of the map, and if so, breaks the scroll lock (since normally, you run across the top of the screen to get to the warp zone - hence, being on top would allow you to proceed there.). Then it adds to the warp zone counter (normally 0 for no warpzone) which turns on the 3 pipes, and kills the process.
Now, were you to go in the normal way, you'd also run into the warp zone scroll lock, which follows special rules. It basically uses some tricks to figure out the right warp zone - if you're in world 1 (which you are), it calls #4, which loads the normal first warp zone. If you're in a world later than world 1, but are in anything that is not a cloud level, it loads the second warp zone at the value 5 (the one that causes the minus world glitch if loaded in the wrong place), and finally if you're in a cloud level it calls 6, the final warp zone.
Forget that. That's what happens in a world in harmony. You're not in that world, here be dragons.
Things get strange now. If you were above the screen, you would encounter this scroll lock before you can access the pipes, which would fix the warps. But if you walk through the wall? You hit the warpzone object but not the scroll lock. This means the counter is at 1 now! Well, what happens is that the game normally takes those numbers 4, 5 and 6, and subtracts 4 to figure out what the correct warpzone counter is (since those 4/5/6 numbers code for the text, and the SMB programmers decided to make the actual warps depend on what the text was). But... 5-4 = 1. And you're already at 1, since that first object added 1 without asking the scroll lock if it's right, and the game blithely accepts whatever's in the variable. This is also why heading all the way to the right shuts the door to the minus world - because the scroll lock is at the end, where the hole you'd drop into the zone from is. So, all said and done, it reads code 5 instead of code 4, and loads the second warp zone - and the pipe on the left has the junk value of 36 (because in the real second warpzone, there is no left pipe), which takes you to level 36.
That was a monster of a description. So why, after all of this, is the minus world an infinite ocean? Doppelganger doesn't quite explain why it's an ocean level, so let's fill in the gaps. The area change from earlier (remember? The sideways pipe?) is the culprit. It's asking us to go to area 1, which is normally where the flag for 1-2 would be, were we still in 1-2. But... since the warpzone hit, we're not being sent to a world that obeys that rule. Instead, we're going to level 36 which... for reasons I'm not sure of, obeys the rules of worlds 2, 3 (though world 3 doesn't have a level that uses these rules, so it's ignored) and 7, which says that you're in a water world, and tells the game about the flag area after the water segment. However! Area changes, checking the world number as they do, can't really even understand what to do with world 36 - so it ends up not loading the end of the level, and just continues forever, since it isn't updating the area change data.
Bonus: The Crazy Levels
It turns out that This same kind of world mismatch can be exploited to lead to yet more worlds. Go back to that Game Genie code. That code alters the game to start you on 36-1... However, you can modify the third part of the code to lead to other values than 36. STart with AOAPYA as the third code bit, and start flipping the first letter, then maybe once you're done with that, the second. Between those two, you'll hit all sorts of other odd level values. From there? You shall gloriously explore!
Happy hunting~
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