fix: update atomic register to u64::MAX-2 to avoid collisions

[austinabell]

When using env and sys calls within the same method, it feels like a foot gun to have the register used for temporary operations to be 0, as most examples and usages I've seen of syscalls use this register.

[ChaoticTempest]

How does this register work usually? I only see it being used for reads so I'm not sure if changing it has any effect besides reading from a different location. Or does the read do something special like create a lock?

[austinabell]

How does this register work usually? I only see it being used for reads so I'm not sure if changing it has any effect besides reading from a different location. Or does the read do something special like create a lock?

Nah, this register is just used as a temporary buffer to be used within the same method call. This changes nothing functionally. The only negative is that someone could potentially be using u64::MAX-2 register with one of these calls sandwiched in between and it would break, but I think this is unreasonably unlikely, and much more of a common pattern for people to use register 0

[ChaoticTempest]

LGTM