Shortly after our Quick End Summer Games 2022 guide went live, the event hosted a fantastic demonstration of a classic video game – one that has since messed with this Ars article’s response. If we want to cut hair, it crosses the classic N64 from 1998 Legend of Zelda: Ocarina of Time is not a ‘speedrun’, but it’s another example of the ‘TASBot’ concept that transforms games in ways we never dreamed of 24 years ago.
The team of fans and programmers responsible for this week’s ‘Triforce-percent’ demo has since revealed how they achieved the feat with nothing but a standard N64 and an original. Ocarina retail cartridge, though the secret involves controller inputs so fast and accurate that they can not be performed by anything less than a computer.
Nothing old in this race
The 53-minute demo (embedded at the end of this article) opens with an exploit previously unearthed in late 2019, which the community called “Stale Benchmark Manipulation.” This exploit exploits a vulnerability in the original 1.0 version of the game that allowed players to manipulate numeric values assigned to specific objects in the game’s memory. The most airy explanation of this complicated technique can be found in a YouTube video from early 2020 (embedded above), as it clarifies the various numerical values assigned to each object in the game, such as their X, Y, and Z axes and rotation.
Experienced players can make the values overlap or overwhelm the original game code so that they can be manipulated as they see fit. The technique we see during this week’s requires Link to pick up a stone while crossing a “loading zone”, once used to hide loading breaks on N64 gear, and do so in a way that the game does not was designed to handle.
Originally, this utilization was a speedrunning tool as it could trick the game into loading the final credit sequence and technically count as a “finish” in just a few minutes. But the Triforce percent race goes much deeper.
INTEGRATES new content into a classic game
By picking up and dropping certain objects, then getting the game’s hero Link to move and perform maneuvers in a certain order, the TASBot team opens a Pandora’s box with so-called random code execution. , the type of vulnerability used by hackers around the world to trick a closed computer system into executing the code they want. In addition, the TASBot motion and command chain begins to tell the N64 to accept button input from all four N64 controllers as if it were code.
At this point, a computer takes over the four ports on the N64 controller and emits a fast series of clicks, as if it were a zillion-fingered superhero similar to The Flash. It failed Ocarina instructed the N64 to accept each button press in a way that matches specific code strings. Once enough of that payload has been sent, the team can resume normal control over the “player one” port so that a real person can play through a whole new sequence of content, all of which is dumped into the N64’s random memory (RAM) of the incredibly fast input from the other three controllers.
These on-the-fly patches can do a lot of amazing things that together look like a fully blown patch of a patron’s ROM, although the TASBot team is limited to changes that apply specifically to the console’s RAM: Small changes to existing code, total file replacements or commands to tell the game to ignore content it would normally load from ROM. As a result, this utilization may fail or decline if players deviate from the expected path for which this utilization is optimized.