I explain how the coin count works in SM64, as well as the other coin-related variables. Because there are multiple variables related to coins and the game doesn’t give each of them a specific name, I just gave them all names that made sense to me. So outside the scope of this video, others (as well as myself) will probably refer to them using slightly different terminology. But within the scope of this video, I’ve defined the variables as follows:
⚫ Coin Count: This is the number of coins Mario has collected so far. It increases instantly when Mario collects coins, namely by +1 for yellow coins, +2 for red coins, and +5 for blue coins. When this variable reaches 100 coins (or goes past it), the 100 coin star appears. This variable is not reset to 0 when Mario leaves a course, but is reset to 0 when Mario enters a course. This variable is a signed short, and so has a range from -32768 to 32767 inclusive. On the NTSC version of the game, it’s capped at 999. On the Japanese version of the game, it has no cap, and so can overflow from 32767 to -32768. When this variable is ≥1000, Mario’s lives will be constantly set to -25.
⚫ Coin Display: This is the value shown up top in the HUD. When this variable is less than the coin count and the global timer is odd, this variable will increment by 1. Thus, pause buffering can be used to prevent this variable from incrementing as it normally would. Once the coin count overflows from from 32767 to -32768, then the condition that this variable be less than the coin count will no longer be true, and so this variable will no longer increment from collecting coins. This variable is a signed short, and so has a range from -32768 to 32767 inclusive.
⚫ Coin Score: This is the highest number of coins collected in each course. Thus, there are 15 of these variables in the game, one for each of the 15 main courses. Right when Mario collects a star, if the current coin count is greater than the current course’s coin score, then this variable is set to the lower byte of the coin count. This variable is an unsigned byte, and so has a range from 0 to 255 inclusive. The coin scores described in this video are the coin scores of the temporary memory. When the game is saved, these values are copied to the corresponding variables of the permanent memory.
⚫ Coin Counter: This is the variable that counts up to how many coins you have after you collect a star and return to the castle. Specifically, it starts at 0 and counts up to the coin display, incrementing by 1 on each frame. If this variable goes above 999, then it will show up as 0, even though it still counts up correctly behind the scenes. This variable is a signed short, and so has a range from -32768 to 32767 inclusive.
Additional Notes
(1) Before anyone starts speculating on the usefulness of multiple 100 coin stars for the A button challenge, please read this. The notion of multiple 100 coin stars has been known for quite some time, and so I’ve already explored its usefulness. In WF, it allows an alternate way to collect the star To the Top of the Fortress in 0x, as demonstrated here: • WF Onto Tower 0xA in J... . However, that strat takes an estimated 10 days to complete, and so it’s inferior to the current strat: • SM64 - To the Top of t... . Concerning the A presses that remain, multiple 100 coin stars would really only be useful in TTC. However, this cannot be achieved, because TTC’s infinite coin method (i.e. coin cloning) doesn’t allow for Mario to collect 65636 coins. That’s because each coin clone occupies an object slot, and there are only 240 of those. So it’s physically impossible to clone more than 240 coins in TTC.