Deconstructing Pokémon glitches?

Question

(I apologize if this is the wrong place to ask this. I think it\'s definitely programming related, though if this belongs on some other site please let me know)

I grew u

Answer 1

I can think of an algorithm (although I feel sorry for whoever might have written it):

• Assume the input is a 32-bit decimal digit in hex notation, little endian (e.g. 0x56 0x34 0x12 0x00).

• Now loop through every byte, while you haven't reached a zero byte. (This should never happen, if 0x999999 is indeed guaranteed to be the max... but alas, it's not.)

• On every loop, calculate the actual value and write the data back into the integer (or into some other buffer, where you do a "loop-while" rather than something like "for i = 0 to 4").

You can see how you can get a glitch, if your value doesn't have 0x00 at the end (i.e. the 32-bit "decimal" integer is larger than 0x999999).

Of course, this is a rather obscure way of calculating the value, but I think it's quite possible that someone did a while/do-while loop rather than a bounded for loop for this.

Edit 1:

At first I thought this would have the "advantage" of allowing the string to be shown directly to the user (since it would be null-terminated), but of course that doesn't work with little endian. They could've done something similar with big endian, but that would require a backwards loop to overflow, which I find to be a less likely mistake for someone to make.

Edit 2:

Perhaps it was a compiler optimization due to undefined behavior (which the programmer was unaware of, like an invalid pointer cast or an aliasing issue)?