16-bit integer overflow I would guess
this post was submitted on 28 Mar 2025
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I found 0xFFFF gold in a knapsack!
Give that man a cigar.
2^16 is 65,536 precisely, one less than that is the number in question. 65,535 is the maximum value of an unsigned 16 bit integer, i.e. sixteen ones in binary: 1111111111111111.
Any nerd who has spent enough time around computers, or at least old computer games, will recognize that instantly as well as the maximum of an 8 bit integer (255) and 32 bit integer (4,294,967,295) because these are inevitably the values you see on your score/money/ammo/whatever counter when you bork your game. Deliberately or otherwise.
1/1/1970 for the epoch
Fun fact: the maximum amount of money you can hold in Maple story is actually half the 32 bit maximum, at 2,147,483,647.
That means it's being stored as a signed integer for some reason. The other half of the binary space is for the negative values, which was probably a poor choice. Unless there is a valid case when you can have negative money. Is debt a thing in Maple Story?
Not at all, but it definitely used to get exploited a lot back in the day.
I bet they thought using signed integers made math easier or something.
Yeah, off-by-one errors are the most common error in programming, and when you are off by +1, and then try to bring it down to 0, it rolls over to max value instead. It makes sense, since some things use 0 as 1 and some things use 1 as 1. The programmer usually just has to memorize which is which... so yeah. Not surprising that it is the most common cause of bugs.