Why Pac-Man Crashes / Glitches on Level 256

It has always been a wonder why Pac-Man crashes on level 256, ever since Billy Mitchell beat Pac-Man back in '99.

The reason for this is because the NES, which runs on 6502 Assembly, was built with an 8 bit processor - the MOS 6502. It had 2 bytes of addressing; 8 bits (1 byte) for the opcode (instruction), and 8 bits for the operand (the value for the instruction). This means that each address could only carry a maximum value of 255 (FF in Hexadecimal) for the instruction. FF is the maximum value a single byte can hold. The processor can only hold a 1 byte value for each instruction per each address.

Therefore, the game will glitch or crash at level 256, because it wasn't programmed to have an ending and to just continue on. The game crashes, because the code isn't telling it to stop, and the memory has been filled.

There, you just learned something new.

By the way, I wrote this in my own words.

It could also start again from 0 because of the overflow xD
But it's obvious that it's an 8 bit limitation just like modern games have a limit of 32 bytes or even 64 bytes usually but that is not so easy to reach. Especially not 64 bit

Honestly if a modern day company were to buy Pac-Man today they might be able to change this error, or glitch. Its not like the people that own it would sell it. But if they did it could be possible to change that value from FF to something greater (maybe)

@ModZ

Yeah, but don't you think 255 levels is more than enough? lol

@Bully

Yes, that's true. It would require a hack or separate program to reach the limit of 32 or 64 bits. It's definitely impossible to do just by playing the game. I found that once you reached round 2,147,483,647 on Zombies, it would reset to level 1. But once you get up to round 100, maybe not even that, it becomes impossible to kill them all. I once spent 3 hours playing a single round with another person, until I said fuck it. Like I said, it's impossible by just playing the game, unless you have hacks.

shitnbitch@BWH wrote:
@Bully

I found that once you reached round 2,147,483,647 on Zombies, it would reset to level 1. But once you get up to round 100, maybe not even that, it becomes impossible to kill them all. I once spent 3 hours playing a single round with another person, until I said fuck it. Like I said, it's impossible by just playing the game, unless you have hacks.

The only weapon that can still kill is the wonder weapon Zeus Cannon/Thundergun since it deals infinite damage. This is how to get to any high round on Zombies for example but of course it's impossible to hit the limit of 32-bit so you're back on round 1 lol

I know for NES games, which were 8 bit, for scores that went up to say, 9,999,999, there would be several addresses for the numbers. One would hold X,XXX, X99, then X,XX9,9XX, tc., where X would be a place holder.

I think... the instruction responsible for this would be an add with carry (ADC), but I could be wrong. Of course with assembly or any programming language, there is easy, quick, simple, straightforward ways, and then there are the opposite ways to writing the same function. This was one of many ways.